ASCP Exam 3 (5/19/23)
Which of the following blood group antigens are most susceptible to destruction by the action of enzymes? A- D B- Jka C- Lea D- Fya
D- Fya Duffy, or Fya and Fyb antigens, are most sensitive to enzyme treatment since they will be destroyed during this process. Enzyme panels can be helpful when multiple antibodies, including Duffy, are present in a patient sample. With the Duffy antigens destroyed, the panel can be performed to identify the remaining antibodies present. Other antigens that are sensitive to enzyme treatment include those of the MNS system and Xga. D, Jka, and Lea are enhanced by enzymes (Rh, Kidd, Lewis, P1, I, and ABO).
Which of the following is NOT considered necessary for making a diagnosis of hereditary hemochromatosis (HH)? A-Laboratory evidence of iron overload B- Genetic mutations associated with HH C- Clinical signs and symptoms consistent with HH D- A positive family history
D- A positive family history Having a positive family history is not considered necessary for making a diagnosis of hereditary hemochromatosis (HH). Laboratory evidence of iron overload, finding genetic mutations associated with HH, along with clinical signs and symptoms consistent with HH, are necessary for confirming a diagnosis of HH.
Which of the following choices is correct when describing the principles of competitive radioimmunoassay procedures? A- Antibody will react preferentially with the labeled antigen B- Antibody will react preferentially with the unlabeled antigen C- Antibody will react with labeled antigen only D- Antibody will react equally with labeled and unlabeled antigen
D- Antibody will react equally with labeled and unlabeled antigen In radioimmunoassay, a fixed concentration of labeled antigen is incubated with a constant amount of antiserum such that the concentration of antigen-binding sites on the antibody is limiting. If an unlabeled antigen is added to this system, there is competition between labeled antigen and unlabeled antigen for the limited and constant number of binding sites on the antibody, and thus the amount of labeled antigen bound to antibody will decrease as the concentration of unlabeled antigen increases.
All of the following statements concerning CK-MB (CK-2) are true EXCEPT: A- Greater than 5% or 10 IU/L followed by an LDH-1: LDH-2 flip is specific evidence of myocardial infarction (MD). B- CK-MB levels can be normal with an elevated total CK. C- CK-MB and troponin levels can be elevated after an AMI. D- CK-MB levels are normal in cardiac ischemia.
D- CK-MB levels are normal in cardiac ischemia. CK-MB would be abnormal in cases of cardiac ischemia since CK-MB is released in higher amounts from cardiac muscle when the heart is damaged or overworked due to various conditions. All the other statements are correct about CK-MB.
A technologist performed a STAT spinal fluid count by pipetting undiluted spinal fluid in a Neubauer Counting Chamber and counting both sides of the chamber (4 large WBC squares on each side). A total of 54 White Cells were counted. How many White Cells would there be per cubic millimeter? A- 3.80 B- 67.5 C- 13.5 D- 300
B- 67.5 First, determine the number of WBC's from the hemacytometer as follows: WBC/µL= Avg # cells counted /(# squares counted x 0.1 µL) WBC = 54 / (8 squares x 0.1 µL) = 67.5/µL Since 1 µL = 1 cubic millimeter, then the answer is 67.5/µL. *Note in this question, both sides were counted without separate values given for the average to be obtained; therefore, substitute the total cell count in the numerator with the total squares counted in the denominator. Also, there was no dilution for the specimen, so the dilution factor will not be included in the equation.
When transporting donated platelet units, what is the maximum amount of time that agitation of platelets can be stopped for? A- 1 hour B- 12 hours C- 24 hours D- 3 days
C- 24 hours Agitation of donated platelet products is necessary for proper gas exchange and to prevent platelet aggregation. This agitation can be periodically discontinued during transportation, but the cessation of agitation cannot exceed 24 hours. Platelet agitation may be ceased for 1 or 12 hours, but neither is the maximum amount of time that cessation may occur. Platelets would not be viable for transfusion if agitation ceased for 3 days.
What is generally accepted as the lower threshold value for semen pH from fertile males? A- 5.5 B- 6.5 C- 7.2 D-8.0
C- 7.2 The lower threshold value of semen pH from fertile males is generally accepted to be 7.2. The normal pH range for semen is 7.2 to 8.0. The specimen should be tested within an hour of collection.
What are the PRIMARY reagents used in the activated partial thromboplastin time (aPTT)? A- Thromboplastin and sodium chloride B- Activated partial thromboplastin and potassium C- Activated partial thromboplastin and calcium D-Actin and sodium chloride
C- Activated partial thromboplastin and calcium In the aPTT procedure, measured amounts of activated partial thromboplastin and calcium are used to activate the clotting process and measure the clotting time. Sodium chloride, potassium, and actin are not used for this reaction. Thromboplastin is one of the key reagents in prothrombin time (PT) testing.
An example of a neoplastic proliferative disease of the plasma cells is: A- Acute Lymphoblastic Leukemia B- B Lymphoblastic Leukemia/Lymphoma C- Multiple Myeloma D- Polycythemia vera
C- Multiple Myeloma The correct answer is Multiple Myeloma, also known as Plasma Cell Myeloma, which is characterized by a proliferation of plasma cells and often an overproduction of one specific immunoglobulin (monoclonal gammopathy). There are several variants of plasma cell myelomas. Acute Lymphoblastic Leukemia, including leukemias of both T and B lymphoblastic origin, are precursor lymphoid neoplasms, whereas Multiple Myeloma is an overproduction of an activated, antibody-secreting B cell. Polycythemia vera is a myeloproliferative disease (of myeloid, not lymphoid origin).
According to the HIV testing algorithm from the CDC, all of the following statements are true, EXCEPT: A- A nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. B- As part of initial screening, an HIV-1/2 antigen/antibody combination immunoassay should be performed. C- An HIV-1/2 antibody differentiation immunoassay should be used to differentiate a positive screening test. D- HIV-1 NAT testing should only be used to resolve any discrepant results between initial reactive testing and nonreactive follow-up testing.
A- A nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. The correct answer is a nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. A nonreactive result must be obtained for both HIV-1 and HIV-2, as well as the p24 antigen, in order to consider a patient negative for HIV. This CDC algorithm allows for earlier detection of infections and overcomes the limitations associated with the use of the western blot test. As part of initial screening, an HIV-1/2 antigen/antibody combination immunoassay should be performed. An HIV-1/2 antibody differentiation immunoassay should be used to differentiate a positive screening test. HIV-1 NAT testing should only be used to resolve any discrepant results between initial reactive testing and nonreactive follow-up testing.
Which of the following statements regarding the L/S ratio is TRUE? A- A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent respiratory distress syndrome (RDS) B- A ratio of 1.5:1 indicates fetal lung maturity in pregnancies associated with diabetes mellitus. C- Sphingomyelin levels increase during the 3rd trimester causing the L/S ratio to fall slightly during the last two weeks of gestation. D- A phosphatidylglycerol (PG) spot indicates the presence of meconium in the amniotic fluid
A- A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent respiratory distress syndrome (RDS) L/S ratio <2.0 indicates an increased risk of respiratory distress syndrome (RDS) at delivery. L/S ratio <1.5 indicates a very high risk of developing RDS Until about 32-33 weeks of gestation, the concentration of these two substances are quite similar; thereafter the concentration of lecithin increases significantly compared with the relatively constant concentration of sphingomyelin. In the absence of complications, the ratio of these two components reaches 2.0 at about 35 weeks gestation. Infants delivered after attaining an L/S ratio of 2.0 or higher rarely develop respiratory distress syndrome (RDS). This value of 2.0 has become the commonly accepted standard value indicating maturity in the fetus of a non-diabetic woman.
Which of the following is the proper designation for the pluripotential stem cell that is a precursor for both myeloid and lymphoid cell lines? A- CFU-S B- CFU-GEMM C- G-CSF D- CFU-GM
A- CFU-S CFU-S stands for colony-forming unit spleen - it is the pluripotential stem cell that gives rise to all cell lines. CFU-GEMM is a multilineage precursor for granulocyte, erythrocyte, macrophage, and megakaryocyte. G-CSF is the precursor committed to granulocyte cell lines. CFU- GM is the precursor for granulocyte and monocyte cell lines.
All of the following are therapeutic drugs used to treat cardiac disease, EXCEPT? A- Carbamazepine B- Digoxin C- Procainamide D- Quinidine
A- Carbamazepine Carbamazepine is an antiepileptic drug used to treat various seizure disorders. Digoxin (used to treat congestive heart failure), Quinidine, and Procainamide (both used to treat cardiac arrhythmias) are common therapeutic cardioactive drugs.
Central Tolerance in the human immune defense system operates by: A- Clonal deletion of T cells and clonal editing of B cells B- Cellular inactivation by weak signaling without a co-stimulus C- Clearance of apototic bodies D- Antigen segregation
A- Clonal deletion of T cells and clonal editing of B cells Central tolerance is characterized by the elimination of immature lymphocytes in primary lymph organs. It is controlled by a mechanism of clonal deletion of T cells and clonal editing of B cells. There are layers of self-tolerance in the human immune system influenced by cellular activity and soluble mediators. The bone marrow and thymus are the sites of action of central tolerance. Central tolerance is initiated during fetal development by the elimination of cells with the potential to react strongly with self-antigens. Cellular inactivation by weak signaling without a co-stimulus describes the mechanism of the layer of the human immune system, peripheral tolerance. Peripheral tolerance is characterized by the elimination of mature lymphocyte clones that occurs in peripheral lymph tissues or clonal anergy. Negative selection is called peripheral tolerance. T cells in the thymus that lack any affinity for self-peptide-self MHC complexes are eliminated in a process called negative selection. B cells undergo negative selection before achieving immunocompetence. Clearance of apoptotic bodies occurs in secondary lymphoid tissue and sites of inflammation. It is characterized by the removal of self-antigen and induction of a negative signal. The layer of tolerance, antigen segregation, takes place in the peripheral organs such as the thyroid and pancreas. The mechanism of action is a physical barrier to self-antigen and induction of a negative signal.
Which laboratory assay is a highly specific indicator and the most sensitive assay for a diagnosis of rheumatoid arthritis? A- Cyclic citrullinated peptide B- Sensitized sheep cells C- Latex particle agglutination D- C-Reactive Protein agglutination
A- Cyclic citrullinated peptide Cyclic citrullinated peptide antibodies are highly specific indicators for rheumatoid arthritis. Antibodies to CCPs (anti-CCP) were first described in 1998. After the introduction of commercial ELISA products using the so-called second generation peptides, there has been increased interest in using this marker in the diagnosis. Anti-CCP antibodies are detectable in about 69-83% of patients with RA and have specificities ranging from 93% to 95%. Compared with other assays for antibodies in RA, CCP is considered to be more sensitive. Antibodies can be detected up to 16 years before the first clinical symptoms of RA appear. Agglutination tests for RF using a sensitized sheep cell test generally detect IgM rheumatoid factors (RFs). IgM RF is manifested in approximately 70% of adults but is not specific for RA. RF has been associated with some bacterial and viral infections, and some chronic infections, and cancer. Elevated values may be observed in the normal older adult population. Agglutination tests for RF using latex agglutination generally detect IgM RFs. Although a latex agglutination procedure has a 95% correlation with a clinical diagnosis of probable or definite rheumatoid arthritis, rheumatoid factor (RF) is not exclusively limited to patients with rheumatoid arthritis. In using latex tests for the detection of RF, a positive result can be expected in less than 5% of healthy individuals. In patients 60 years old and older, as many as 30% may be seropositive. C-Reactive Protein (C-RP) is a rapidly synthesized, acute phase reactant. It is an indicator of acute inflammation. Traditionally, C-RP has been used clinically for monitoring infection, autoimmune disorders, and, more recently, healing after myocardial infarction. The C-RP rapid latex agglutination test is based on the reaction between patient serum containing C-RP as the antigen and the corresponding antihuman (C-RP) coated to the surface of latex particles. The latex particles allow for easy visual detection of an antigen-antibody reaction. The clinical applications of C-RP are evaluation, including detecting inflammatory disease, particularly infections, screening for inflammatory and malignant disease, and monitoring therapy in inflammatory disease.
Which values would be expected with metabolic alkalosis? A- Elevated pH, increased bicarbonate, normal PCO2 B- Elevated pH, decreased bicarbonate, normal PCO2 C- Lowered pH, normal bicarbonate, decreased PCO2 D- Increased pH, normal bicarbonate, increased PCO2
A- Elevated pH, increased bicarbonate, normal PCO2 When using determining the acid-base status of a person, the parameters that may vary due to conditions of the patient would be the pH (acidosis = < 7.35 or alkalosis = > 7.45), bicarbonate (HCO3-1), and PCO2 (partial pressure of carbon dioxide). If the bicarbonate changes, it would be considered metabolic. If the bicarbonate increases, the pH increases and it would be metabolic alkalosis. For example, this could happen through excess administration of sodium bicarbonate. If the bicarbonate decreases, the pH decreases, and this would be metabolic acidosis. For example, excessive loss from diarrhea. If the carbon dioxide changes, it would be considered respiratory. A decrease in PCO2 would actually increase the pH and it would be respiratory alkalosis which could be caused by hyperventilation conditions. An increase in PCO2 would actually decrease the pH and it would be respiratory acidosis which could be caused by hypoventilation conditions.
Recently the American Diabetes Association (ADA) recommended reporting which of these values in order to correlate with hemoglobin A1C (HbA1C) as a further indicator of glycemic control? A- Estimated average glucose B- Blood urea nitrogen C- Microalbumin D- Insulin
A- Estimated average glucose In 2008, the ADA recommended calculating and reporting the estimated average glucose (eAG) with HbA1C measurement results. The eAG can be calculated from percent HgA1C by using the following formula: eAG (mg/dL) = 28.7 X HgA1C - 46.7
Which one of the following procedures is used for the proper preparation of platelet concentrate from random whole-blood donors? A- Light spin followed by a hard spin B- Light spin followed by two hard spins C- Two light spins D- Hard spin followed by a light spin
A- Light spin followed by a hard spin The correct answer is a light spin followed by a hard spin. The first step in the preparation of platelets from random whole blood donors is low-speed centrifugation (light spin). This allows the platelets to remain in the plasma portion of the collection container. The plasma (dubbed "platelet-rich plasma") is then centrifuged at a higher velocity (hard spin) that forces the platelets to the bottom of the satellite bag. The platelet-poor plasma is expressed into another container, and the residual platelets that remain in the bag are resuspended in a small volume of plasma.
Which of the following organisms is a cause of cutaneous infections? A- Nocardia brasiliensis B- Nocardia cyriacigeorgica C- Nocardia farcinica D- Gordonia bronchialis
A- Nocardia brasiliensis Nocardia brasiliensis causes cutaneous infection after the organism enters the skin or subcutaneous tissues. It is the most frequent cause of nocardiosis, which is usually seen in the hands and feet as a result of outdoor activity. Nocardia cyriacigeorgica and Nocardia farcinica both cause pulmonary infections. Gordonia bronchialis has been isolated from postsurgical sternal wounds and has caused coronary artery and central venous catheter infections.
Laboratory tests which can contribute toward the diagnosis of Glanzmann Thrombasthenia include all of the following EXCEPT: A- PT and aPTT B- Non-anticoagulated blood films (e.g. smears from a finger stick) C- Platelet aggregation tests D- Flow cytometry
A- PT and aPTT PT and aPTT are normal in Glanzmann Thrombasthenia, so this information would not contribute significantly toward a diagnosis. Non-anticoagulated blood films will show a characteristic total lack of platelets aggregating as they usually do when making blood smears such as from finger sticks. This would contribute toward a possible diagnosis. Platelet aggregation tests are abnormal in Glanzmann Thrombasthenia using all agonists except ristocetin. This helps to distinguish it from other aggregation problems but is generally insufficient alone for diagnosis. Flow cytometry can yield a more definitive diagnosis. Platelets in Glanzmann Thrombasthenia would show a decrease in platelet GPIIb-IIIa receptors. (Molecular techniques could then go on to characterize the exact mutations in GPIIb-IIIa.)
What procedure utilizes leukapheresis to collect the buffy coat from whole blood? A- Photopheresis B- Plasmapheresis C- Therapeutic apheresis D-Erythrocytapheresis
A- Photopheresis Photopheresis utilizes leukapheresis to collect the buffy coat layer from whole blood. These cells are treated with 8-methoxypsoralen, exposed to ultraviolet A light and then reinfused into the patient. Photopheresis has been shown to be efficacious and has been approved by the Food and Drug Administration for the treatment of cutaneous T-cell lymphoma. Plasmapheresis is the removal and retention of the plasma, with return of all cellular components to the patient. Therapeutic apheresis (TA) involves the removal of a specific blood component, with return of the remaining blood constituents to the patient. However, with TA the component being removed is considered pathological or contributing to the patient's underlying disease state. Erythrocytapheresis, or red cell exchange, removes a large number of red blood cells from the patient and returns the patient's plasma and platelets along with compatible allogeneic donor red blood cells.
The quality control term used to describe the number of patients with an abnormal test result who have the disease being tested for by an assay compared to all patients with an abnormal result is: A- Positive predictive value B- Negative predictive value C- Specificity D- Sensitivity
A- Positive predictive value A positive predictive value of an assay is described as the number of patients with an abnormal test result who have the disease being tested for in the assay compared to all patients with an abnormal result. A negative predictive value of an assay is described as the number of patients with a normal test result who do not have the disease being tested for in the assay compared with all patients with a normal (negative) result. Specificity is the term used to describe the proportion of patients with an absence of a specific disease or condition that gives a negative test result Sensitivity is the term used to describe the proportion of cases with a specific disease or condition that give a positive test result.
A hospitalized patient has a decreased serum copper level and increased urine copper level. This is MOST consistent with: A- Wilson's disease B- Addison's disease C- Parathyroid disease D-Not clinically significant
A- Wilson's disease Wilson disease is a rare inherited disorder that causes the body to retain copper. Serum copper is paradoxically low but urine copper is elevated in Wilson's disease. Copper is deposited in tissues such as hepatic parenchymal cells, brain cells, and the periphery of the iris. Symptoms include hepatitis, neurological disorders, and renal tubular dysfunction. Addison's disease is an endocrine disorder where the adrenal glands do not produce enough steroid hormones. Parathyroid disease is categorized as hyper or hypoparathyroidism, which affects parathyroid hormone and calcium levels. Increased urine copper and decreased serum copper are clinically significant findings.
Which of the following enzymes is associated with conditions affecting skeletal muscles? A-Aldolase B- Alkaline phosphatase (ALP) C- Gamma-glutamyltransferase D- 5'-nucleotidase
A-Aldolase Aldolase is an enzyme that aids in the glycolytic breakdown of glucose to lactate for energy. Aldolase is associated with muscles and is currently used in the monitoring of patients with muscular dystrophy and a few other rare conditions affecting skeletal muscles. A serum ALP measurement's most useful clinical attribute is its sensitivity in distinguishing hepatobiliary disease associates with biliary tree obstruction. It is also used to detect bone disease associated with an elevated osteoblastic activity. Gamma-glutamyltransferase, or GGT, is elevated in liver diseases affecting the biliary system, especially in patients who are heavy drinkers. Serum concentrations of 5'-nucleotidase, or 5NT, reflect hepatobiliary disease with high specificity as well.
Beer's law states that concentration is directly proportional to which of the following? A- Light transmitted B- Absorbance C- Incident light D- Absorptivity coefficient
B- Absorbance Beer's law states that absorbance is directly proportional to concentration. In Beer's law, light transmitted is indirectly proportional to concentration and is therefore indirectly proportional to absorbance. ncident light is used to calculate transmittance. The absorptivity coefficient is the amount of light absorbed by an analyte at a specific wavelength and is constant for an analyte. It is used in the calculation for absorbance.
The accuracy of an immunoassay is its ability to discriminate between results that are true positive and results that are true negative. Two parameters of test accuracy are specificity and sensitivity. Which of these statements apply to an immunoassay with high specificity? A- Accurately identifies the presence of disease B- Accurately identifies the absence of disease C- Has many false-positives D- Has few false-negatives
B- Accurately identifies the absence of disease A test with high specificity accurately detects the absence of disease. The more specific a test is, the fewer false-positive results will occur. A test with high sensitivity accurately identifies the presence of disease. The more sensitive a test, the fewer false-negative results it produces. In the case stated in this question, the immunoassay has high specificity, so it has few false-positives and will accurately detect those individuals who do not have the disease or condition that is being tested for.
Which of the following antibodies usually show enhanced agglutination with the use of proteolytic enzymes? A- Anti-M,-N, and -S B- Anti-Jka, -Jkb, -C, and -E C- Anti-Fya and -Fyb D- Anti-K
B- Anti-Jka, -Jkb, -C, and -E Enzyme techniques are particularly useful in the identification of antibodies in the Rh system (e.g., anti-C and -E) and in the Kidd system (e.g., anti-Jka and -Jkb). Enzymes destroy some antigens, such as M, N, S, Fya, and Fyb. Therefore the corresponding antibodies would not be detected. Enzymes do not affect the K antigen or antibodies against the K antigen.
The arrangement of erythrocytes (Rouleaux) on this peripheral blood smear may be seen in each of the following conditions EXCEPT? A- Hypergammaglobulinemia B- Cold agglutinin disorders C- Monoclonal gammopathy D- Chronic infection
B- Cold agglutinin disorders Cold agglutinin disorders is the correct answer. The arrangement of the RBCs documented in the photomicrograph is called rouleaux formation, resembling a stack of coins. Rouleaux may be seen on the blood smear when plasma proteins are increased, particularly fibrinogen and gamma globulins, as seen in hypergammaglobulinemia, monoclonal gammopathies, and chronic infection. True rouleaux may be assessed only in the thin area of the smear. Pseudorouleaux is seen in the thicker area of the smear. Red blood cell agglutination (clumping) rather than rouleaux formation appears in conditions where cold reactive antibodies, most commonly IgM, circulate in the plasma.
Which of the following processes does NOT occur during primary hemostasis? A- Physical decrease in the size of damaged vessel (vasoconstriction). B- Fibrin strands added to the newly formed clot. C- Blood flow rerouted around the damaged vessel. D- Platelets adhere to exposed collagen at the site of the breach.
B- Fibrin strands added to the newly formed clot. Primary hemostasis refers to the role of blood vessels and platelets in response to vascular injury. Blood vessels contract to seal the wound and reduce the blood flow (vasoconstriction). Platelets become activated, adhere to the site of injury, secrete the contents of their granules, and aggregate with other platelets to form a platelet plug. Secondary hemostasis involves the activation of coagulation proteins to form a fibrin clot. Activation of coagulation proteins results in the formation of thrombin, an enzyme that converts fibrinogen to fibrin. Fibrin strands are not added to the newly formed clot during primary hemostasis as this is the basis of secondary hemostasis. Vasoconstriction, rerouting of blood flow, and platelet adhesion to exposed collagen at the site of the injury all occur during primary hemostasis.
An electrophoretic separation of lactate dehydrogenase isoenzyme that demonstrates elevation in LD-1 greater than LD-2 could be indicative of: A- A normal LD isoenzyme pattern B- Hemolysis C- Pancreatitis D- Hepatic injury
B- Hemolysis Hemolysis, both in vivo and in vitro, can cause elevations in LD-1 and LD-2. Also, LD-1 and LD-2 are both increased during myocardial infarction since they are both present in the heart muscle. In normal conditions, LD-2 is present in higher concentrations than LD-1. The reverse is true in myocardial infarction and during states of hemolysis. This term is referred to as the LD flip. Pancreatitis does cause increased levels of LD, but the LD-3 type is the most affected in this condition. Hepatic injury also increases levels of LD, but the LD-4 type is the most affected in this condition.
In examining a Wright's stained blood smear of a patient who has had a splenectomy, one would most likely also find: A- Heinz bodies B- Howell-Jolly bodies C- Auer rods D-Dohle bodies
B- Howell-Jolly bodies Howell-Jolly bodies are often found in the peripheral blood after a splenectomy. They are composed of a small, round RBC inclusion of DNA. Howell-Jolly bodies can also be seen in megaloblastic anemia. Heinz bodies can be seen in mature RBCs as a dark blue/purple inclusion of denatured hemoglobin when using a supravital stain such as new methylene blue. These inclusions can be seen in conditions such as hemoglobinopathies and G6PD deficiency. Auer rods are needle-like inclusions within the cytoplasm of leukemic myeloblasts. Dohle bodies, oval aggregates of rough endoplasmic reticulum, are found in the cytoplasm of WBCs in association with inflammation, infection, severe burns, May-Hegglin anomaly, etc.
A major action of angiotensin 2 is: A-Increased pituitary secretion of petressin B- Increased vasoconstriction C- Increased parathormone secretion by the parathyroid D-Decreased adrenal secretion of aldosterone
B- Increased vasoconstriction Angiotensin 2 is an oligopeptide in the blood that causes vasoconstriction of arterioles, increased blood pressure, and release of aldosterone from zona glomerulosa of the adrenals. Aldosterone in turn induces sodium retention in the collection ducts of the kidney, subsequently conserving water and increasing vascular volume.
The antibody most frequently present in systemic lupus erythematosus (SLE) patients is directed against: A- Myelin B- Nuclear antigen C- Surface antigens of bone marrow stem cells D- Surface antigens of renal cells
B- Nuclear antigen The anti-nuclear antigen test, or ANA test, is a valuable screening tool for systemic lupus erythematosus (SLE). Demonstration of ANAs can indicate various systemic autoimmune connective tissue disorders characterized by antibodies that react with different nuclear components such as double stranded DNA, single-stranded DNA, and Sm (Smith) antigen. ANAs are classified into antibodies to DNA, antibodies to histones, antibodies to nonhistone proteins, and antibodies to nuclear antigens. Antimyelin-associated glycoprotein is associated with chronic sensorimotor demyelinating neuropathy. Various hematologic conditions can be caused by alloantibodies or autoantibodies. Antibodies associated with autoimmune conditions can be secondary to Mycoplasma pneumoniae infection, viral infections , lymphoma, or drugs. Immunologic renal disease can be associated with four categories of diseases, one of which is circulating immune complexes. Renal diseases associated with circulating immune complexes are caused by nonrenal antigens and their corresponding antibodies. Studies have suggested that potentially damaging immune complexes may be formed in situ and involve antigens already present or fixed in the glomerulus. In addition, immune complex activation of complement in the glomerular basement membrane may be augmented by the presence of cells with receptors for C3 located in that area. Activation probably releases biologically active products such as chemotactic substances and causes an inflammatory type of tissue injury. A renal complication of this type can be manifested in SLE. Neuropathy syndromes are associated with antibodies directed against peripheral nerve components. For example, the antibody antimyelin-associated glycoprotein is associated with chronic sensorimotor demyelinating neuropathy. Various hematologic conditions can be caused by alloantibodies or autoantibodies. Antibodies associated with autoimmune conditions can be secondary to Mycoplasma pneumoniae infection, viral infections, lymphoma or drugs. Immunologic renal disease can be associated with four categories of diseases, one of which is circulating immune complexes. Renal diseases associated with circulating immune complexes are caused by nonrenal antigens and their corresponding antibodies. Studies have suggested that potentially damaging immune complexes may be formed in situ and involve antigens already present or fixed in the glomerulus. In addition, immune complex activation of complement in the glomerular basement membrane may be augmented by the presence of cells with receptors for C3 located in that area. Activation probably releases biologically active products such as chemotactic substances and causes an inflammatory type of tissue injury. A renal complication of this type can be manifested in SLE.
Which one of the following is a detergent added to gel media that enhances the separation of solutes during electrophoresis? A- Ampholyte solution B- Sodium dodecyl sulfate C- Zwitterion D- Silica
B- Sodium dodecyl sulfate Sodium dodecyl sulfate (SDS) is added to a gel to denature proteins and enhance their separation. Polyacrylamide gels often include this detergent to achieve greater resolution of solutes.
Which of the following statements about high-frequency antigens is correct? A- High-frequency antigens are common and it is easy to identify their corresponding antibodies. B-High-frequency antigens are common, but it is difficult to identify their corresponding antibodies. C- High-frequency antigens are rare and it is difficult to identify their corresponding antibodies. D- High-frequency antigens are rare, but it is east to identify their corresponding antibodies.
B-High-frequency antigens are common, but it is difficult to identify their corresponding antibodies. The correct answer is high-frequency antigens are common, but it's difficult to identify their corresponding antibodies. High-frequency antigens are present in >98% of all individuals. Occurrence of an antibody to these antigens is rare because most individuals have these antigens on their red cells. Looking for antigen negative, compatible blood would be difficult because <2% of the population would be negative for the antigen. Identifying the antibody to a specific high-frequency antigen would be challenging due to the presence of other high-frequency antigens on the panel. All high-frequency antigens tend to be present on every panel cell. Trying to rule out each individual antigen would be difficult since there would be no negative panel cells.
An 8-year-old boy presents with a 2-week history of high fevers and lethargy. He has shown petechiae and bleeding gums for approximately 3 weeks. Upon physical examination, the following was noted: Enlarged cervical lymph nodes, pale and febrile, enlarged spleen His laboratory results were the following: Hgb = 6.3g/dL Hct = 18.9% RBC count = 2.89 x 109/L WBC Count = 96 x 109/L Platelet count = 23 x 109/L Differential: 90% blasts, 5% bands, 5% neutrophils BM aspirate > 90% blasts What is this patient most likely suffering from? A- Polycythemia vera B- Chronic leukemia C- Acute leukemia D- Infectious mononucleosis
C- Acute leukemia A high white blood cell count with many blasts in the peripheral blood and bone marrow, along with a low platelet and RBC count, are associated with acute leukemia. WHO classification of acute leukemia includes > 20% blasts in the bone marrow. There is an arrest in the maturation process of these malignant cells resulting in the accumulation of the immature cells. Further testing must be done to classify the exact subclass of acute leukemia. Given the patient's age, acute lymphoblastic leukemia is the most likely as ALL is the most common childhood leukemia. Polycythemia vera is a myeloproliferative disorder that usually presents with increased RBC count, granulocytes, and platelets. The median age is 60 years old. Chronic leukemias are characterized by leukocytosis and excessive proliferation of mature blood cells. There may be some immature cells present, but they are capable of maturation. Chronic leukemias are typically considered a disease of adults in their 50's or 60's. Infectious mononucleosis is a benign lymphoproliferative disorder caused by the Epstein-Barr virus. Most patients present with a leukocytosis from 10 to 20 x 109/L. About 10% of individuals present with leukopenia. Patients present with variant or reactive lymphocytes. These reactive lymphocytes are present in a variety of sizes and shapes. Usually, they are large with wandering cytoplasm that may be indented by the adjacent RBCs. The cytoplasm may be more basophilic at the periphery of the cell.
If an R1r patient received R2R2 blood, which of these antibodies could be produced? A- Anti-c B- Anti-D C- Anti-E D- Anti-ce
C- Anti-E The R1r patient = DCe/ce. The R2R2 = DcE/DcE. Since the E antigen is not present in the R1r, when introduced with the R2R2 patient's blood, anti-E could be produced. Anti-c would not be produced since both the patient and the donor have the c antigen. Anti-D would not be produced since both the patient and the donor have the D antigen. Anti-ce would not be produced since the donor's blood does not have the e antigen and the recipient has the e antigen.
Which substance is used in the Jendrassik-Grof method to accelerate the reaction of unconjugated bilirubin with the diazo reagent? A- NADH B- N-butanol C- Caffeine-benzoate D- Acetic acid
C- Caffeine-benzoate The caffeine-benzoate solution is used to split the unconjugated bilirubin protein complex releasing the bilirubin so that it can react with diazotized sulphanilic acid. The tartrate buffer creates an alkaline solution and converts the red acid bilirubin to a blue-colored compound which can be measured spectrophotometrically at 600nm
Which one of the following drugs/drug classes is the MOST COMMON cause of drug-induced immune hemolytic anemia? A- Levodopa B-Quinidine C- Cephalosporins D-Levofloxacin
C- Cephalosporins Each of the drugs/drug classes listed above has been known to cause drug-induced immune hemolytic anemia (DIIHA), although cephalosporins are the MOST COMMON cause. Cephalosporins can cause drug-induced immune hemolytic anemia when a patient produces antibodies to the particular cephalosporin drug in the presence of red blood cells. The drugs can alter the membrane appearance of the red blood cells, causing the body to mistake them as foreign. Complement becomes activated due to these antibodies; red cells are then destroyed, causing hemolytic anemia. Dark urine, caused by intravascular hemolysis, is one of the most common symptoms associated with this condition.
A patient grew out Mycobacterium tuberculosis (MTB) from an acid-fast bacilli (AFB) sputum culture. The physician called requesting information on alternative choices for the treatment of MTB since the patient had tested resistant to the primary drugs of choice. Which of the following antitubercular agents would be recommended for treatment? A- Streptomycin B- Isoniazid C- Ciprofloxacin D- Ethambutol
C- Ciprofloxacin Ciprofloxacin is the correct answer. Secondary antitubercular agents used in the treatment of MTB are Ethionamide, Capreomycin, Ciprofloxacin, Doxycycline or minocycline, Ofloxacin, Kanamycin, Cycloserine, Rifabutin, and Trimethoprim-sulfamethoxazole. If resistance to any of the primary drugs is detected, a combination of secondary drugs can be used. Streptomycin, Isoniazid, and Ethambutol are all incorrect answers. All three drugs are classified as primary antitubercular agents against MTB in addition to Rifampin and Pyrazinamide. Initial isolates of MTB are tested against all five agents and used as a first-line treatment option.
For which of these reasons would a molecular method not be used? A- Determine blood type when the DAT is positive B- Complex Rh genotypes (weak D expression) C- Donor antibody screening D- Type fetal blood
C- Donor antibody screening Applications of molecular testing in blood bank include donor antigen screening not donor antibody screening. Other applications include determining blood type when the DAT is positive, identifying complex Rh genotypes, and typing fetal blood.
The LD (lactate dehydrogenase) molecule is made of a combination of polypeptides that can be separated into isoenzymes that help determine the location of an elevated LD. LD 3 is found primarily in the lung, lymphocytes, spleen, and pancreas but what polypeptides makeup LD 3? A- HMMM B- MMMM C- HHMM D- HHHM
C- HHMM The correct answer is HHMM for LD 3. HMMM is LD 4 and found in the liver; MMMM is LD 5 and found in skeletal muscle; HHHM is LD 2 and found in the heart and red blood cells.
The gel electrophoresis pattern for hemoglobin S (HbS) shows which of the following migration patterns? A- HbS migrates alone in alkaline and with HbD in acid electrophoresis. B- HbS migrates with HbD in alkaline and with HbA in acid electrophoresis. C- HbS migrates with HbD in alkaline and alone in acid electrophoresis. D- HbS migrates with HbA in alkaline and HbD in acid electrophoresis.
C- HbS migrates with HbD in alkaline and alone in acid electrophoresis. HbS migrates with HbD (and HbG) in alkaline and alone in acid electrophoresis. On cellulose acetate (pH 8.6 = alkaline), HbS appears between HbF and HbA2.%0D%0AOn citrate agar (pH 6.2= acidic), HbS appears between HbC and HbA .
The small mass of chromatin located in the nucleus of protozoa is called the: A- Cytostome B- Peripheral chromatin C- Karyosome D-Micronucleus
C- Karyosome The karyosome is condensed chromatin within the nucleus of protozoa. The relative karyosome size (small vs. large) along with the location of the karyosome in relation to its surrounding nuclear membrane (central vs. eccentric) are key features that aid in the identification of the amebae. The cytostome, or oral groove, is the mouth part of Chilomastix mesnili. It is located outside of the nucleus that contains the karyosome The presence or absence of peripheral chromatin on the nuclear membrane is another identifying characteristic of the protozoa. If the peripheral chromatin is present, it may be described as beading, fine, or clumped. The micronucleus is only found in the ciliated protozoa Balantidium coli. The micronucleus is located in the hilum of the macronucleus of this organism.
Which of the following distinguishing characteristic is associated with Streptomyces species? A- Partial acid-fast organism B- Resistance to lysozyme C- Musty basement odor D- Salmon pink colonies
C- Musty basement odor All of these characteristics can be used when differentiating the aerobic Actinomycetes. Streptomyces species, can be suspected when an unknown isolate emits a musty basement odor. Basements smell musty because they have these bacterial species growing in the dust and soil. Partially acid-fast organism does not describe Streptomyces species, it describes Nocardia species and is one way to differentiate between the two organisms. They both can have a musty odor with similar dry, chalky colonies. Streptomyces is partial acid-fast negative and Nocardia is partial acid-fast positive. Resistance to lysozyme does not describe Streptomyces species, it describes Nocardia species. Another way to differentiate these organisms is by using growth in lysozyme. Nocardia will grow in the presence of lysozyme (resistant) and Streptomyces will not (sensitive). Salmon-pink colonies do not describe Streptomyces species, but Rhodococcus equii can be suspected.
Which of the following cells demonstrate an increase in osmotic fragility? A- Target cells B-Reticulocytes C- Spherocytes D- Macrocytes
C- Spherocytes The correct answer is spherocytes. Spherocytes get their shape because of a decreased surface-to-volume ratio. The hemoglobin that occupies a normal-sized biconcave RBC now occupies the smaller volume of a spherocyte. When spherocytes are exposed to hypotonic solutions, they hemolyze quicker than normal-sized, biconcave cells would. Osmotic fragility is the most useful test for confirmation of hereditary spherocytosis. Target cells, also known as codocytes, have an increased surface-to-volume ratio. They would not demonstrate an increased osmotic fragility. Reticulocytes are immature RBCs and are slightly larger than a mature RBC. They, too, have an increased surface-to-volume ratio. Macrocytes are larger than normal RBCs. An MCV>100 indicates the presence of macrocytic cells. Most macrocytic cells have normal hemoglobin concentrations and, therefore, would have an increased surface-to-volume ratio. These cells would have a decreased osmotic fragility.
These 3 tubes of cerebrospinal fluid (CSF) are delivered to the laboratory for analysis. The tube labeled #1 was the first tube collected. Which one of the tubes should be used by the hematology department for cell count and differential? A- Tube #1 B- Tube #2 C- Tube #3 D- Any one of the tubes can be used
C- Tube #3 Hematology analysis is typically performed on the last tube collected to ensure that any peripheral blood that may have contaminated the sample during the lumbar puncture has cleared. In this case, only 3 tubes were collected. Therefore, tube #3 should be used for cell count and differential. The first tube collected should not be used for hematology analysis because of possible blood contamination from the lumbar puncture. Tube #1 is used for chemistry and immunology testing as any contamination (blood or bacteria) is removed by centrifuging the sample prior to analysis. Tube #2 is used for microbiology because any bacterial contamination introduced during the lumbar puncture should be washed into tube #1 and any blood contamination that remains will not affect microbiology testing. As a last resort, cell count and differential procedures can be performed on any tube, but it should be noted in the report. It is not standard operating procedure.
It's a busy Friday evening in the blood bank, and you have been receiving a steady stream of Type & Screen specimens from the emergency room. Several of them have positive antibody screens, which require further workup. One of these patients is a 46-year-old male whose hemoglobin has dropped from 8.4 g/dL to 4.6 g/dL in the previous 8 hours (normal Hgb for this patient demographic would be ~14 g/dL). Your workup reveals a group O patient with the following antibodies: anti-K, anti-Fya. The prevalence of K negative donors in your donor population is 91%, while the prevalence of Fya negative donors is 37%. Two units of cross-matched RBCs are requested by the physician. How many units of group O RBC units should you phenotype in order to fulfill the request for two cross-matched units? A- 2 units of type O RBC units B- 3 units of type O RBC units C-6 units of type O RBC units D- 12 units of type O RBC units
C-6 units of type O RBC units Based on the antigen prevalence information provided, you will need to test 6 units of group O RBC units in order to get 2 units of group O RBC units that are negative for both the K and Fya antigens. STEP 1: The percentage of donors negative for each antigen should be written in decimal points, and then multiplied: 0.91 (K negative) X 0.37 (Fya negative) = 0.33 STEP 2: Next, find the reciprocal of the number found in the first step. In other words, divide 1 by the number you calculated in the first step: 1/0.33 = 3 3 units should be antigen typed in order to find a single unit negative for both of these antigens. Remember - you need to crossmatch TWO units, so you would actually need to antigen type 6 units to find two that could be crossmatched. An alternate method to determine the number of units to antigen type is to solve for x using a ratio. In this case the ratio would be: 33/100 = 2/x 33x = 200 x = 6.06 or approximately 6 units
A 90-year-old patient is admitted to the hospital with the following laboratory data: WBC: 9,000/mm3 PLT: 190,000/mm3 Hgb: 6.1 g/dL Differential: 11% Neutrophils 40% Lymphocytes 4% Monocytes 45% Myeloblasts 45 NRBC's / 100 WBC Bone Marrow: 45% Myeloblasts & 55% Megaloblastoid Erythroblasts Serum Vitamin B12 and Folic Acid: Normal The MOST likely diagnosis is: A- Pernicious anemia B- Polycythemia vera C-Erythroleukemia D- Myelomonocytic leukemia
C-Erythroleukemia Erythroleukemia is also known as Acute Myelogenous Leukemia type M6. This type is associated with either the presence of both erythroid and myeloid precursors OR strictly erythroid precursors. In the case above, there are both erythroid and myeloid precursors present in the peripheral smear. Pernicious anemia would have shown an abnormal serum vitamin B12 level and would not have been associated with the myeloid precursors or the large amount of erythroid precursors demonstrated in this case. Polycythemia vera is associated with very high levels of red cells, white cells, and platelets, which is not found in this case. Finally, myelomonocytic leukemia is associated with an increase in myeloid and monocytic cell precursors, but not red blood cell precursors.
The use of the direct antiglobulin test is indicated in all the following EXCEPT: A- Transfusion reactions B- Autoimmune hemolytic anemia C- Hemolytic disease of the newborn D- Detection of alloantibodies in serum
D- Detection of alloantibodies in serum The direct antiglobulin test (DAT) detects antibodies coating RBCs. In transfusion reactions, the DAT detects recipient antibody coating donor RBCs. In autoimmune hemolytic anemia, the DAT detects autoantibody coating an individual's RBCs. In hemolytic disease of the newborn, the DAT detects maternal antibody coating fetal red cells. Alloantibodies are primarily detected in the serum, although they may also sometimes be eluted from previously transfused RBCs in the patient's blood. Alloantibodies are detected by the indirect antiglobulin test (IAT).
The function of the very low-density lipoproteins (VLDL) is to transport: A- Cholesterol from peripheral cells to the liver B- Cholesterol and phospholipids to the peripheral cells C- Exogenous triglycerides D-Endogenous triglycerides
D-Endogenous triglycerides VLDL transports endogenous (hepatic-derived) lipids to the peripheral tissues during fasting periods for energy utilization and storage, whereas chylomicrons transport exogenous (dietary) lipids to the hepatic and peripheral cells. Cholesterol is transported by HDL and LDL.
The Carba NP confirmatory test is used to detect all of the following carbapenemases EXCEPT? A-KPC (Klebsiella pneumoniae carbapenemase) B- NDM-1 (New Delhi metallo-beta-lactamase) C- VIM (Verona integron-encoded metallo-beta-lactamase) D- ESBL (Extended Spectrum Beta-Lactamase)
D- ESBL (Extended Spectrum Beta-Lactamase) ESBL (Extended Spectrum Beta-Lactamase) is the correct answer because ESBL is an enzyme that hydrolyzes penicillins and cephalosporins, including the extended-spectrum cephalosporins (cefixime, ceftriaxone, ceftizoxime, and ceftazidime). This enzyme does not affect the carbapenem drugs imipenem or meropenem. KPC (Klebsiella pneumoniae carbapenemase), NDM-1 (New Delhi metallo-beta-lactamase), and VIM (Verona integron-encoded metallo-beta-lactamase) are incorrect answers because the Carba NP confirmatory test is used to detect these carbapenemases that can be seen in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter species. This test is a colorimetric test that uses imipenem and phenol red indicator. If a yellow color is produced, this indicates that a carbapenemase is present. If no color is produced, no carbapenemase is present.
Which of the following best describes the benefits of the RPR or VDRL tests: A- Diagnostic of active syphilis B- Diagnostic of latent syphilis C- Diagnostic of neuro-syphilis D- Monitoring course of treatment
D- Monitoring course of treatment While the RPR and VDRL tests are often the first screening test used to detect syphilis, a definitive diagnosis of syphilis can only be made using a specific treponemal test such as EIAs for IgG and IgM antibodies, agglutination tests such as FTA-ABS, TP-PA, and MHA-TP, or a direct detection method of the organism. The RPR and VDRL detect nontreponemal antibody proteins called reagin that the body produces in response to infection with T. pallidum. Because reagin proteins are also detected in pregnancy, old age, Lupus, and other syndromes and disease states, the RPR and VDRL tests are very sensitive but not highly specific, and so a confirmatory test specifically for treponemal organisms or antibodies needs to be performed.
Neisseria species can be traditionally differentiated by their fermentation of sugars. Identify the biochemical reaction that goes with the correct species of Neisseria given. A- N. gonorrheae = Glucose +, maltose -, lactose + B- N. lactamica =Glucose -, maltose -, lactose - C- N. cinera = Glucose +, maltose +, lactose + D- N. meningitidis = Glucose +, maltose +, lactose -
D- N. meningitidis = Glucose +, maltose +, lactose - As a mental reminder, gonorrhoeae = G = glucose; meningitidis = M = maltose; and, lactamica = L = lactose. N. gonorrhoeae is only positive for glucose, while N. meningitidis is positive for maltose and glucose, and N. lactamica is positive for all three sugars. N. cinerea is asaccharolytic using conventional carbohydrate fermentation tests. Some strains of the N. cinera species have given positive reactions for glucose using reagent test systems, potentially causing a problem in the misidentification of Neisseria gonorrhoeae. To differentiate those N. cinera isolates that ferment glucose, N. cinera grows at 35°C and reduces nitrite, unlike N. gonorrhoeae.
While working at a blood bank laboratory, you hear chimes over the hospital loudspeaker system announcing the birth of a baby. Thirty minutes later, you receive a cord blood specimen that you identify as O positive. You previously received the mother's specimen and she was O negative with a negative antibody screen. What is the next action? A- Issue one vial of RhIg B- Perform a Kleihauer Betke stain C-Nothing - Mom is not at risk for anti-D D- Perform a fetal bleed screen
D- Perform a fetal bleed screen Because the baby is D positive and the mom is D negative and not currently immunized to the D antigen, mom will need to receive at least one 300 µg dose of RhIg. However, we must first perform a fetal bleed screen to determine if a fetal-maternal hemorrhage (FMH) has occurred If a FMH occurred, the fetal bleed screen would be positive, and a Kleihauer Betke stain is required. In some institutions, FMH is quantified with flow cytometry studies. If the FMH is 30 mL or less, 1 vial of RhIg is indicated. For a FMH larger than 30 mL, a calculation is completed to determine how many vials of RhIg must be issued.
Plasma creatinine concentration is dependent on all of the following EXCEPT: A- Relative muscle mass B-Renal function C- Rate of creatinine turnover D- Sodium concentration
D- Sodium concentration Plasma creatinine levels are not impacted by sodium concentration. Plasma concentration of creatinine is a function of relative muscle mass, the rate of creatinine turnover, and renal function. The amount of creatinine in blood is fairly stable. The amount of protein in a person's diet does impact plasma creatinine concentrations.
Which of the following is the ideal method for processing wound swab specimens for a Gram stain and culture? A- Specimen should be collected on a single swab that should be used to directly inoculate all media and prepare the smear. B- Specimen should be collected on a dual swab collection device, in order to allow for one swab to be used to directly inoculate all media and prepare the smear, while the second swab should be stored in case additional testing is requested. C- Specimen should be collected on a dual swab collection device, in order to prepare a smear with one swab, while the second swab should be centrifuged to create a concentrated specimen. D- Specimen should be collected on a single swab that will be placed in 1.0 mL of saline and vortexed. The saline solution should then be used to inoculate all media and prepare the smear.
D- Specimen should be collected on a single swab that will be placed in 1.0 mL of saline and vortexed. The saline solution should then be used to inoculate all media and prepare the smear. The correct answer is that the specimen should be collected on a single swab that will be placed in 1.0 mL of saline and vortexed. The saline solution should then be used to inoculate all media and prepare the smear. Placing the swab into saline and vortexing will loosen material from the swab and produce an even suspension of organisms. A sterile pipette should be used to inoculate the media with the saline suspension and prepare the smear. Using a single swab to directly inoculate the media and prepare the smear may yield discrepant results, as there may not be enough organisms on the swab to be detected on the media and the smear. Swabs often retain organisms, which may lead to a false negative Gram stain and/or culture. Using a dual swab device would likely allow for greater correlation between the Gram stain and the culture if one swab is used to directly inoculate the media and the second swab is used to prepare the smear, but retaining the second swab is of no use, as additional testing beyond a Gram stain and culture from a swab is unlikely It is not necessary to centrifuge swabs, as there is no liquid to concentrate.
All of the following are characteristics of cast, EXCEPT? A- They are cylindrical bodies. B- They are formed either in the distal convoluted tubules or the collecting ducts of the kidney. C- They contain Tamm-Horsfall mucoprotein. D- They are formed in the urethra.
D- They are formed in the urethra. Casts are cylindrical bodies formed either in the distal convoluted tubules or the collecting ducts of the kidney, not the urethra The matrix of all casts is thought to be Tamm-Horsfall protein, a glycoprotein secreted by the distal loop of Henle and the distal tubule. This protein entraps cells and granular material of tubular origin. After formation, casts are loosened from the tubules and discharged into the urine. Casts, if present, are visible in freshly voided urine.
