AAB MT Cert
Which of the following is used to standardize the bacterial inoculum used in a disk diffusion test (Kirby-Bauer method)? The correct answer is highlighted below 0.1 McFarland standard 0.5 McFarland standard 1.0 McFarland standard 2.0 McFarland standard
A 0.5 McFarland Standard is used to prepare a sample for a standard disc diffusion (Kirby-Bauer) susceptibility test. The 0.5 McFarland standard is also used for the preparation of inocula in standardized agar dilution, broth macro and microdilution, and anaerobic organism susceptibility test procedures.
Increased concentration of alpha-fetoprotein (AFP) in adults are most characteristically associated with: The correct answer is highlighted below Hepatocellular carcinoma Alcoholic cirrhosis Megaloblastic anemia Multiple myeloma
AFP is one of the oncofetal proteins which are produced in high concentration during fetal life. AFP is produced by the fetal yolk sac and liver. Oncofetal proteins usually disappear or are reduced to very low concentrations after birth. Increased alpha-fetoprotein levels in adults is usually associated with hepatocelluar carcinoma, as it is a tumor maker in this population. Alcoholic cirrhosis, megaloblastic anemia, and multiple myeloma would not cause an increase in serum AFP.
Which of the following statements about monocyte function is INCORRECT? The correct answer is highlighted below Monocytes are white blood cells that are actively phagocytic in the peripheral blood. Monocytes are white blood cells that are actively phagocytic in the body tissues. Monocytes are white blood cells that can continue to develop into macrophages. Monocytes are white blood cells that play an important role in inflammatory diseases.
Although monocytes are phagocytic cells, they function in the tissues and organs, and rarely, if ever, in the peripheral blood. Driven by chemokines and cell adhesion molecules, monocytes exit the vessels and migrate to tissues and organs throughout the body, where they are phagocytic and secrete cytokines. Monocytes can further develop into macrphages which also function throughout the body as phagocytes. (Macrophages often have different names depending on their location in the body). Monocytes can secrete various cytokines which can have both pro-inflammatory and anti-inflammatory activities (depending on the monocyte subset).
Which of the following is associated with an increased susceptibility to infection in AIDS patients? The correct answer is highlighted below Decreased CD4+ cells Decreased CD8+ cells Decreased HIV antigens Decreased HIV antibodies
CD4 positive lymphocytes, or T-helper cells are critical in an immune response against pathogens. HIV directly attacks CD4+ cells along with monocytes, macrophages, dendritic cells and microglial brain cells. CD8+ cells will demonstrate a relative increased due to the decrease in CD4+ cells. A decrease in HIV antigens is not associated with increased risk of infection. Decreased in HIV antibodies is not associated with an increased risk of infection.
Charcot-Leyden crystals in stool may be associated with an immune response and are thought to be the breakdown products of: The correct answer is highlighted below Neutrophils Eosinophils Monocytes Lymphocytes
Charcot-Leyden crystals in stool are thought to be created from damaged eosinophil byproducts. These crystals have a strong association, although they are rare, with parasitic infections or allergic reactions.
Which of the following conditions would have macrocytic red cells? The correct answer is highlighted below Liver disease and Vitamin B12 deficiency Iron deficiency and thalassemia Hereditary spherocytosis and hereditary elliptocytosis G6PD deficiency and malaria
Chronic liver disease and Vitamin B12 deficiency would present with incrased MCV and macrocytosis. Iron deficiency and thalassemia would present with decreased MCV and microcytosis. Hereditary spherocytosis and hereditary elliptocytosis would present with normal MCV and normocytic red cells. G6PD deficient patients and patients with malaria would have normal MCVs and normocytic red cells.
At a minimum, the following class of biological safety cabinet (BSC) must be used when manipulating potential bioterrorism agents and if aerosols are likely: The correct answer is highlighted below Class I BSC Class II BSC Class III BSC Class IV BSC
Class II BSC sterilizes the air in the cabinet and the air to be exhausted. This type of BSC is required for working with aerosols and dangerous, highly virulent organisms such as bioterrorism agents. Class I BSC allows unsterilized air to flow in and around the material inside. Only the air exhausted is sterilized. It is not sufficient to work with bioterrorism agents. Class III BSC is completely enclosed with the air being filtered and sterilized as it comes in and as it goes out. Agents requiring this environment also require the worker to use rubber gloves that are attached and sealed to the cabinet. Class IV BSC does not exist.
Illustrated in the top image is a slow-growing, 8-day-old colony growing on Sabouraud Dextrose with Brain Heart Infusion (SabHI) agar obtained from a darkened superficial skin infection. Although the colony is not specific for one of the fungal species causing chromomycosis, the black outer border that extends into the reverse of the colony is consistent. The identification is made by observing the distinctive conidiation illustrated in the bottom image. Which of the following organisms is represented by the description and images shown? Please select the single best answer Exophiala jeanselmei Fonsecaea pedrosoi Cladophialophora carronii Phialophora verrucosa
Cladophialophora carronii is the correct response. Colonies are slow growing and are not specific. Distinctive for making the identification of cladosporium-type sporulation, as seen in microscopic mounts, are hyphae giving rise to long chains of dark-staining, elliptical conidia each separated by a scar called a dysjunctor. Its colony is gray-green to black with a black reverse. Exophiala jeanselmei is incorrect. Exophiala jeanselmei sporulation is in the form of darkly stained conidiophores that branch from the pigmented hyphae. The conidiophores terminate in sharply pointed tips, from which loose clusters of small, elliptical pigmented conidia are produced. Fonsecaea pedrosoi is incorrect. Fonsecaea pedrosoi sporulation is of the acrotheca-type that is characterized by the sympodial branching of conidiophores produced from the ends of septate hyphae, simulating the prongs of a coat rack. Short chains of elliptical conidia are produced from the tips of these conidiophores. This species is the most common cause of chromoblastomycosis and produces a mixed type of sporulation that is characteristic of the Cladosporium, Phialophora, and Rhinocladiella species. Phialophora verrucosa is incorrect. Phialophora verrucosa sporulation is characterized by the production of short urn-shaped phialides with a narrow bottle-like opening derived laterally from the sides of the hyphae. Spherical of oval-shaped, yellow pigmented conidia are produced from within each phialide, forming loose aggregates at the terminal opening.
Direct examination of treponemes can be performed by: The correct answer is highlighted below Light microscopy examination Darkfield microscopy examination VDRL testing Rapid Plasmin Reagin (RPR) testing
Darkfield microscopy allows for direct observation of spirochetes from an active syphilitic lesion. It is the test of choice for examining symptomatic patients with primary syphilis. A darkfield examination is also suggested for immediate results in cases of secondary syphilis. The traditional logarithm for syphilis testing of suspected patients with syphilis begins with observations of classic lesions present, suggestive sexually transmitted infection history, and current sexually transmitted disease. Non-treponemal testing such as the Rapid Plasmin Reagin (RPR) is the next step. A reverse sequence testing algorithm begins with the same patient observations but the next step is to perform treponemal testing by chemiluminescence immunoassay or enzyme immunoassay. Light microscopy examination is not effective in the detection of spirochetes. Darkfield or fluorescent microscopy techniques are required for direct observation of spirochetes. The VDRL assay is a flocculation test that measures IgM and IgG antibodies to lipoidal material released from damaged host cells, to lipoprotein-like material, and possibly to cardiolipin released from the treponemes. Without some other evidence for the diagnosis of syphilis, a reactive nontreponemal test does not confirm T. pallidum, infection. Antilipoidal antibodies are antibodies that are not only produced as a consequence of syphilis and other treponemal diseases, but also may be produced in response to nontreponemal diseases of an acute or chronic nature in which tissue damage occurs. Rapid Plasmin Reagin (RPR) testing is a non-treponemal testing method. Traditionally, it is the next step in serological assessment. The RPR is the most widely used assay to determine the presence of regain, an antibody formed against cardiolipin, a lipid remnant of damaged cells, cholesterol, and lecithin, is used to detect the nontreponemal regain antibodies.
Six months ago, a 55-year-old female had a fasting plasma glucose (FPG) greater than 200 mg/dL on two occasions. She was diagnosed as having type 2 diabetes and treatment was started. Along with routine FPG's which of the following tests would most likely be used to monitor glycemic control? The correct answer is highlighted below HbA1C Insulin C-peptide Urine glucose
FPG is performed to monitor diabetes, often weekly or even daily. The ADA also recommends that a HbA1C be tested at least twice a year to monitor long-term glycemic control. HbA1C reflects long-term blood glucose concentration for a patient, it provides the clinician with a picture of glucose concentration over the past 120 days. A level of HbA1C =6.5% is indicative of diabetes mellitus. Individuals with levels between 5.7% to 6.4% are considered at high risk for developing diabetes.
Which of the following will impact platelet aggregation when it becomes deficient? The correct answer is highlighted below Factor XIII Fibrinogen Stuart-Prower Factor Factor VIII
Fibrinogen plays critical roles in coagulation through the ability to form bridges for platelets to aggregate. It also converts into fibrin to form a fibrin clot to stabilize the platelet plug further. Factor XIII is also known as the Fibrin Stabilizing Factor. This factor's function is to stabilize the fibrin clot after formation and does not act in platelet aggregation. Stuart-Prower Factor is Factor X which is the start of the Common Pathway. It does not have a purpose in platelet aggregation. Factor VIII is found within the Intrinsic Pathway and does not have a purpose in platelet aggregation.
What is the approximate percentage of individuals in the US who are heterozygous for HFE mutations for hereditary hemochromatosis? The correct answer is highlighted below 0.05% to 0.10% 1% to 2% 10% to 12% 20% to 25%
Hemochromatosis is a form of iron overload, or accumulation of excess iron. The condition affects the skin, liver, pancreas (traditionally called "bronzed diabetes"), and the heart. Hemochromatosis may be an acquired condition or inherited. In hereditary form of hemochromatosis, a mutation in the HFE gene is the most common cause. Early diagnosis and treatment can prevent these secondary effects of iron overload. Approximately 10% to 12% of individuals in the US are heterozygous for HFE mutations. The most common causative HFE mutation is the homozygous Cys282Tyr (C282Y) mutation. Prevalence is high in white population (homozygote 3-5%) but almost absent in non-white population. In northern Europeans, heterozygosity approaches 13%.
Which analyte is MOST useful for monitoring long-term (~12 weeks) stability of blood glucose? The correct answer is highlighted below Lactic acid Urinary ketone bodies Insulin Glycosylated hemoglobin (HbA1C)
Hemoglobin A1C (HbA1C), also known as glycosylated hemoglobin, has the ability to measure an approximate 3 month period of glucose control. HbA1c is the nonenzymatic addition of a glucose molecule to HbA. After a rearrangement, the addition is irreversible. HbA1c reflects long-term blood glucose concentration for a patient and it provides the clinican with a picture of a patient's average glucose concentration over the past 120 days. A level of HbA1c =6.5% is indicative of diabetes mellitus. Individuals with levels between 5.7% to 6.4% are considered at high risk for developing diabetes.
Human chorionic gonadatropin (hCG) is used in the determination of: The correct answer is highlighted below Liver function Fetal maturity Pregnancy Steroid levels
Human chorionic gonadatropin (hCG) is a hormone produced in pregnancy that is made by the developing embryo and later produced by the placenta. Its role is to maintain progesterone production that is critical for a healthy pregnancy.
What is the mechanism that causes megaloblastic anemia? The correct answer is highlighted below Defective stem cell production Interruption of hemoglobin production Interruption of DNA Synthesis Interruption of development of precursor cells
Interruption of DNA synthesis results in the development of a megaloblastic anemia. Defective stem cell production results in the development of aplastic anemia. Interruption of hemoglobin production results in thalassemia. Interruption in the development of precursor cells is an anemia that is caused by chronic renal disease.
In the condition kernicterus, the abnormal accumulation of bilirubin occurs in what tissue? The correct answer is highlighted below Brain Liver Kidney Blood
Kernicterus literally means "yellow kern," with kern indicating the most commonly afflicted portion of the brain and is associated with severe jaundice. This condition is caused by a build up of unconjugated bilirubin in the bloodstream from the breakdown of red blood cells.
Which of the following organisms are aerobic, Gram negative diplococci that do not ferment sugars and is DNAse positive? The correct answer is highlighted below Neisseria lactamica Moraxella catarrhalis Kingella kingae Veillonella parvula
Moraxella catarrhalis is a common laboratory isolate that is distinguished from other Gram negative diplococci, including Neisseria species and Kingella species, by not fermenting any of the commonly tested carbohydrates and is DNAse positive. It is also aerobic. N. lactamica is a Gram negative diplococci but ferments glucose, maltose lactose, while K. kingae is a Gram negative coccobacilli that ferments glucose and maltose. Veillonella parvula is an infrequently recovered anaerobic Gram negative diplococcus that also has the properties of being asaccharolytic and failing to hydrolyze DNA.
Which of the following coagulation test results would be prolonged in deficiency of Factor X? PT only aPTT only Both PT and aPTT Neither PT nor aPTT
PT monitors Factor VII plus the common pathway factors (X, V, II and I). aPTT monitors Factor VIII, Factor IX, Factor XI, Factor XII and the common pathway factors. Therefore, both PT and aPTT monitor the common pathway factors (X, V, II, I). In a Factor X deficiency, both PT and aPTT results would be prolonged.
The image on the right is representative of the peripheral blood smear from a five-month-old immigrant from Asia. Her mother was concerned that the child was not eating well. Her spleen was palpable. These blood count results were reported: Parameter Patient Result Reference Interval RBC 5.5 x 1012/L 3.1 - 4.5 x 1012/L Hgb 9.6 g/dL 9.5 - 13.5 g/dL HCT 30.4% 29- 41% MCV 55.4 fL 74 - 108 fL MCH 17.5 pg 25 - 35 pg MCHC 31.6 g/dL 30 - 36 g/dL RDW 34.9% 11 - 15% Reticulocyte 10.9% 0.5 - 4.0% Knowing that the family is from a region of Thailand where HbE carriers are prevalent, the physician ordered a hemoglobin electrophoresis. The hemoglobin electrophoresis detected HbE. Based on the blood count results and this representative microscopic field, which of the following peripheral blood findings should be reported? Please select the single best answer Microcytes (microspherocytes), target cells, nucleated red blood cells Macrocytes, target cells, nucleated red blood cells Sickle cells, target cells, and malarial parasites Microcytes, target cells, and malarial parasites
Peripheral blood smear findings of microcytes or microspherocytes, target cells, and nucleated red blood cells should be reported. Macrocytes are not present. The MCV result correlates with a finding of microcytes. A few red blood cell fragments may be seen, but sickle cells are not present. The inclusion that is noted in this field is a cell nucleus in a nucleated red blood cell and not a blood parasite. Homozygous hemoglobin E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hemoglobin E is uncommon in North America and in Europe, but with changing immigration patterns, Hb E cannot be ignored. Clinically, a very important and severe syndrome is hemoglobin E/beta thalassemia in which there is hemolysis requiring repeated transfusions. The patient would have a severe anemia, low MCV, and high RBC. This is characteristic of Hgb E/beta thalassemia.
Which of the following would best be determined by running the same control specimen multiple times: The correct answer is highlighted below Regression Reliability Accuracy Precision
Precision is a measurement of a method's ability to repeatedly produce the same value on a given specimen after multiple measurements. It is usually estimated by running the same specimen at least 20 times and calculating the standard deviation. Regression refers to a measure of the relation between the mean value of one variable (x) and corresponding values of other variables (y). Reliability refers to the degree to which the result of a measurement, calculation, or specification can be depended on to be accurate. Accuracy refers to the degree to which the result of a measurement, calculation, or specification conforms to the correct value or a standard.
What is a typical regimen for long-term maintenance therapy of individuals with hereditary hemochromatosis (HH)? The correct answer is highlighted below Removal of 2 to 6 units of blood yearly Dietary restrictions on iron intake only Treatment with desferrioxamine Removal of one unit of blood once per week
Removal of 2 to 6 units of blood yearly, or about 500 mL every three months, is a typical regimen for long-term maintenance therapy of individuals with HH. Note one unit of blood is approximately 500 mL. While dietary restrictions on iron intake may be recommended, it would alone not be sufficient therapy. Desferrioxamine is used to minimize excess iron due to many blood transfusions (for patients with chronic anemia). It may also be used to treat young children with iron poisoning. Removal of one unit of blood once per week would likely cause the patient to become anemic.
Which of these organisms is associated with the condition known as toxic shock syndrome? The correct answer is highlighted below Clostridium difficile Staphylococcus aureus Enterococcus faecalis Micrococcus luteus
S. aureus infections range from superficial, localized skin infections, such as folliculitis, to deeper, more serious skin lesions and the more serious toxin mediated conditions such as scalded skin syndrome and toxic shock syndrome. S. aureus is a Gram positive, aerobic cocci. C. difficile is the causative organism of ulcerative colitis, a sometimes fatal inflammation of the colon. C difficile is a Gram positive, anaerobic, spore-forming bacilli. E. faecalis infections range from endocarditis to UTIs, but Entercocci lack the toxins that cause toxic shock syndrome. E. faecalis is an aerobic, Gram positive cocci. M. luteus is usually considered a contaminant of cultures as it rarely causes human disease. M. luteus is a Gram positive, aerobic cocci.
What is the International Normalized Ratio (INR) calculation used for? The correct answer is highlighted below Standardize PT and aPTT results Standardize PT results between different reagent sensitivities Standardize aPTT results between different reagent sensitivities Calibrate coagulation instruments for all coagulation testing
Standardize PT results between different reagent sensitivities
All of the following are sources of serum alkaline phosphatase EXCEPT: The correct answer is highlighted below Liver Placenta Intestine Brain
The source of elevated alkaline phosphatase can be identified by electrophoresis of tissue specific isoenzymes at alkaline pH. Liver, bone, intestine, and placenta are the most commonly identified isoenzymes.
Which test is NOT used as a screen for retroviruses in donated blood? The correct answer is highlighted below Antibody to HIV type 1 or type 2 Nucleic acid testing to detect HIV-1 RNA Antibody to HTLV types I and II Nucleic acid testing for HCV
Three tests are currently used as a screen for retroviruses in donated blood: antibody to HIV type 1 or type 2 (anti-HIV-1/2), nucleic acid testing (NAT) to detect HIV-1 RNA, and antibody to HTLV types I and II (anti-HTLV-I/II). Positive results using NAT for HCV are approved by the FDA to confirm a reactive HCV antibody test. Also, hepatitis C is not considered a retrovirus.
The profusion of tiny microconidia lining up along the hyphae in this photomicrograph is characteristic of which of the following organisms? The correct answer is highlighted below Epidermophyton floccosum Trichophyton verrucosum Trichophyton rubrum Microsporium audouinii
Trichophyton rubrum is the correct answer because the tiny microconidia are lined up in a "birds on the fence" arrangement along the hyphal strand transversing the field of view (yellow arrows). Two pencil-shaped, smooth walled macroconidia are also seen in the lower left field of view (red arrows). Epidermophyton floccosum is incorrect because of the inability of this dermatophyte to produce microconidia. Two to four-celled, club-shaped macroconidia are produced, usually in clusters of two or three. Trichophyton verrucosum is incorrect because they are irregularly arranged with little tendency to line up along the hyphae. Antler hyphae and string bean macroconidia are characteristic of this species. Microsporium audouinii is incorrect because they produce rare bizarre shaped macroconidia with few or absent microconidia. May only see terminal chlamydospores.
Nephelometry and turbidimetry measure different properties of: The correct answer is highlighted below Fluorescence in turbid solutions Free ions in solution UV light at 360 nm Light transmission and scatter by particles in suspension
When light strikes a particle in a solution, it can be absorbed, transmitted, reflected, or scattered. Nephelometry is used to measure the light scattered by particles in a solution. Turbidimetry measures the light transmitted by particles in a solution. These are useful techniques for measuring protein levels in fluids, and antigen-antibody complexes.
A 300 µg dose of RhIg can suppress immunization up to a maximum of _____ mL of D-positive whole blood. The correct answer is highlighted below 15 mL 20 mL 25 mL 30 mL
A 300 µg dose of RhIG can suppress immunization of up to approximately 30 mL of D-positive whole blood, or 15 mL of D+ red cells. One vial would be sufficient for fetomaternals bleeds less than 30 mL whole blood as well, including 15 mL, 20 mL, and 25 mL.
Which is the best method for examination of synovial crystals? The correct answer is highlighted below Phase contrast Darkfield microscopy Brightfield microscopy Polarized light
A polarizing microscope with a first order red compensator is used to identify crystals in synovial fluid: Needle shaped monosodium urate crystals are strongly negatively birefringent, while rhomboid calcium pyrophosphate crystals are weakly positively birefringent.
Which of the following would be a possible cause of a positive direct antiglobulin test (DAT)? The correct answer is highlighted below Transfusion reaction and warm autoimmune disease only Warm autoimmune disease and clot tube stored at 4°C only Clot tube stored at 4oC and transfusion reaction only Clot tube stored at 4oC, transfusion reaction, and warm autoimmune disease.
A positive DAT is associated with transfusion reactions, warm autoimmune disease, clot tube stored at 4oC, cold autoimmune disease, drug interactions, and hemolytic disease of the fetus and newborn.
What is the maximum concentration of a chemical allowable for repeated exposure without producing adverse health effects called? The correct answer is highlighted below Threshold limit value Time-weighted average Ceiling Value Short-term exposure limit
A threshold limit value (TLV) is the maximum concentration of a hazardous material to which healthy adult workers can be exposed during an 8-hour workday and 40-hour workweek—over a working lifetime—without experiencing significant adverse health effects. Time-weighted average (TWA): The concentration of a contaminant averaged over a workday (usually 8 hours long) and should not be exceeded for up to an 8-hour workday during a 40-hour workweek. Ceiling value: A concentration of a toxic substance in air that American Conference of Governmental Industrial Hygienists (ACGIH) recommends should not be exceeded at any time during the workday. Short-term Exposure Limit (STEL) value: A TWA concentration over 15 minutes that ACGIH recommends not to exceed—even if the 8-hour TWA is within the standards. TWA-STELs are given for contaminants for which short-term hazards are known.
Which of the following is a FALSE statement regarding the use of extension cords in a health care facility? The correct answer is highlighted below An extension cord should only be used in an emergency situation. The extension cord should be tested for physical integrity, polarity, and continuity of grounding before it is used. An extension cord used in a healthcare facility can be either a two-prong or three-prong cord. An extension cord must contain a ground wire.
An extension cord used in a health care facility must be a three-pronged cord. If an extension cord needs to be used, it must consist of 16 gauge or larger wire and must contain a ground wire. An extension cord should only be used in an emergency situation in the clinical laboratory. The extension cord should be tested for physical integrity, polarity, and continuity of grounding before it is used. An extension cord used in the healthcare setting must contain a ground wire.
Other than signing an informed consent form, a patient may give consent for a venipuncture procedure through all of the following actions EXCEPT: The correct answer is highlighted below Rolling up a shirt sleeve. Holding out his or her arm. Turning his or her arm over into the correct position for phlebotomy procedure. Nodding in agreement with the information shared by the health care provider.
An informed consent form is signed by the patient for approval of medical treatment including venipuncture procedures. In lieu of signing the informed consent form, patients may give consent through all of the following actions: rolling up his or her shirt sleeve, turning his or her arm to the correct position for the venipuncture procedure, and holding out his or her arm. Without acceptable informed consent, any touch (including intent to collect blood samples for testing) can be considered a criminal offense. A simple nodding gesture will not suffice or constitute consent.
Contact dermatitis is mediated by: The correct answer is highlighted below B lymphocytes Mast cells Polymorphonuclear cells T lymphocytes
Contact dermatitis is an example of a cell-mediated (Type IV) hypersensitivity reaction that involves macrophages and T lymphocytes. When an antigen comes in contact with the skin, the antigen is processed by cells in the epidermis and comes in contact with T lymphocytes. T lymphocytes recognize the antigen as foreign and circulate through the bloodstream back to the epidermis. There, they release cytokines that produce an inflammatory response, causing a characteristic rash in the skin called contact dermititis. B lymphocytes produce antibodies, and these are not involved in contact dermatitis. Mast cells are a key component of Type I hypersensitivity reactions, not cell-mediated hypersensitivity. Polymorphonuclear cells are recruited to the sites where immune complexes have formed in Type III hypersensitivity reactions.
Which of the following is the deferral period following the collection of double red blood cell units? The correct answer is highlighted below 1 year 16 weeks 8 weeks 4 weeks
Donors taking part in double RBC apheresis programs are deferred for 16 weeks following their last donation. To qualify to participate in a double RBC apheresis program, there are requirements for height, weight, and hemoglobin/hematocrit that are greater than the requirements for a regular, one-unit of whole blood donation. A person who donated a standard unit of whole blood is deferred for 8 weeks after their last donation.
A patient has a urinalysis performed and results are: Leukocyte esterase: Positive Nitrate: Positive What organism would the tech expect to find on the urine culture plates? The correct answer is highlighted below E. coli Staphylococcus aureus Enterococcus faecalis Candida albicans
E. coli would be the most likely organism to show up on culture due to the urinalysis result. The key is that nitrates are positive. E.coli and other Enterobacteriaceae reduce nitrates to nitrites and will provide a positive nitrate on urinalysis. Positive leukocyte esterase also helps to determine that inflammation is present and possibly infection but does not help us point at a specific organism as this would be positive for infection with any type of organism. Staphylococcus aureus and Enterococcus faecalis are gram positive cocci and would not show a positive nitrate test on the urinalysis. Candida albicans in a yeast and would not show a positive nitrate test on the urinalysis.
Which of the following is characteristic of an exudate effusion? The correct answer is highlighted below Leukocyte count greater than 1000 WBC/uL Clear appearance Protein concentration less than 3.0 g/dL Absence of fibrinogen
Effusion is the increase of fluid between the serous membranes due to distruption of the mechanisms of formation and reabsroption of serous fluid. Exudates are caused by conditions affecting the particular cavity such as infections and malignancies. Exudate effusion characteristics include: Leukocyte count greater than 1000 WBC/µL Fluid : Serum Protein ratio > 0.5 Yellow or cloudy appearance Possible spontaneous clotting
The diagnostic stage for helminths is: The correct answer is highlighted below Egg Trophozoite Oocyst Microfilaria
Egg is the correct answer. The diagnostic stage for helminths is the presence of eggs, larvae, or adult worms in a direct wet mount of a stool specimen. For example, Ascaris lumbricoides. Trophozoite is incorrect. Trophozoites are best found in fresh stool specimens that have been permanently stained with a stain such as trichrome. The presence of amoeba cyst is also helpful in the diagnosis of amoeba, such as Entamoeba histolytica. Oocyst is incorrect. Oocysts are typically best diagnosed in stool specimens using either the zinc sulfate flotation method of removing fecal debris and/or by the modified acid-fast stain procedure. Oocyst can be seen in Cryptosporidium species. Microfilaria is incorrect. Loa loa microfilariae are typically seen on Giemsa-stained blood smears collected between 10:00 am and 2:00 pm, when the recovery rate is the best.
All of the listed disorders are organ non-specific autoimmune diseases EXCEPT: The correct answer is highlighted below Systemic lupus erythematosus (SLE) Systemic sclerosis (SSc) Rheumatoid arthritis (RA) Hashimoto's disease
Hashimoto's disease or Lymphoid Chronic Thyroiditis is an endocrine disorder and a classic example of an organ-specific autoimmune disease. In this example, the autoimmune process in which the development of circulating cytotoxic antibodies eventually destroy the thyroid gland and produce hypothyroidism. Organ-specific, autoimmune disease are produced by T cells or antibodies against antigens restricted to a single organ. In organ-specific diseases both the lesions produced by tissue damage and the auto-antibodies are directed at the same organ. Systemic lupus erythematosus (SLE) is a classic example of a systemic autoimmune disease produced by circulating antibodies or immune complexes and affects multiple end organs. The terms, systemic, refers to multiple systems in the body. Organ nonspecific diseases are characterized by the presence of both lesions and autoantibodies that are not confined to any single organ. Systemic sclerosis (SSc), Progressive Systemic Sclerosis, or Scleroderma is a collagen vascular disease. Idiopathic scleroderma is considered an autoimmune disease because of the associated autoantibodies and the overlapping syndromes of scleroderma-polymyositis and scleroderma-SLE. The term, rheumatic disease, does not have a clear boundary with more than 100 different conditions being labeled as rheumatic diseases, including rheumatoid arthritis (RA). RA is a chronic, multi-system, autoimmune disorder a progressive inflammatory disorder of the joints. The current model of the pathogenesis of RA proposes that an infective agent or other stimulus binds to receptors on dendritic cells, that activate the innate immune system.
Which of the following hematology tests is used to indicate anemic conditions? The correct answer is highlighted below Platelet count White blood cell count White blood cell differential Hemoglobin
Hemoglobin is the iron containing protein in red blood cells responsible for caring oxygen to the tissues. Low levels of hemoglobin are indicative of anemia. The white blood cell (WBC) count helps determine if leukocytes respond abnormally to certain conditions such as bacterial or viral infections. A high WBC count could also be indicative of malignant conditions such as leukemia. Platelet counts are used in the determination of bleeding disorders. Values may also be used to monitor chemotherapy or radiation treatments. White blood cell differential (Diff) test is used to classify different types of leukocytes, describe erythrocyte morphology, and estimate platelets. Values may also be used to monitor chemotherapy or radiation treatments.
FALSE-NEGATIVE results at the indirect antiglobulin phase of an antibody screening test using a tube method (i.e., not a Gel-method) are usually caused by which of the following? The correct answer is highlighted below Excessive washing of the red cells Inadequate washing of the red cells Warm autoantibody present in the patient's serum Cold autoantibody present in the patient's serum
If an antigen-antibody reaction has occurred, but washing is inadequate, free antibodies that have not attached to antigens on the red blood cells remain when the anti-human globulin (AHG) is added. The AHG is bound by the free antibody rather than attaching to the antibody on the red blood cells, causing a false-negative result. This false-negative result is detected by using Check Cells as a control. If the free antibody has already been bound by the AHG, there is no free AHG serum to react with the Check Cells, and no agglutination will occur. A warm or cold-autoantibody would not affect the result of an antiglobulin test if washed properly.
In healthy individuals, calcitonin is synthesized by which cells in the body? The correct answer is highlighted below Hepatocytes Leukocytes Thyroid C cells Red blood cells
In healthy individuals, calcitonin is only synthesized by the thyroid C cells. Calcitonin is released as a response to increased serum calcium. It inhibits bones from releasing further calcium and thus reducing serum calcium concentration.
A CSF specimen was sent to the laboratory for analysis. A glucose, protein, and cell count were performed. Based on the following results, what would be the probable cause? Analyte Result Glucose 15 mg/dL Protein 150 mg/dL Leukocytes 1,000 cells/mm3 neutrophils The correct answer is highlighted below Normal CSF Viral infection Purulent infection Tuberculosis or fungal infection
Purulent infection is correct. For a CSF to be considered purulent, the glucose value should be <45 mg/dL, the protein value should be >100 mg/dL, and the leukocyte count should average 800 cells/mm3 (range 5-20,000 cells/mm3) with polymorphonuclear cells predominating. The glucose value is low because bacterial organisms are using the glucose as an energy source for growth and the protein value is elevated due an increase in cellular presence. Normal CSF is incorrect. To be considered normal, the glucose value must be within 45-100 mg/dL, the protein must be within 15-50 mg/dL, and the leukocyte count must be within 0-5 cells/mm3 with no predominant cell line. Viral infection is the incorrect answer. In a viral infection, the spinal fluid will have a normal glucose value (range 45-100 mg/dL), a slightly elevated protein value (range 15-50 mg/dL), and an average leukocyte count of 80 cells/mm3 (range 0-5 cells/mm3) with mononuclear cells predominating. Tuberculosis or fungi infection is incorrect. In this type of infection, the glucose value is low to normal, the protein value is >50 mg/dL, and the leukocyte count is around 100 cells/mm3 with mononuclear cells predominating.
A patient had a differential diagnosed of Systemic Lupus Erythrematosus (SLE). Laboratory Results: ANA = positive (homogeneous pattern), titer 1:320, RA=positive, Complement = decreased. All of the following specific laboratory tests meet the criteria for a definitive diagnosis of SLE, EXCEPT? The correct answer is highlighted below A positive antinuclear antibody (ANA) Smith (Sm) antibodies Double-stranded DNA (dsDNA) antibodies Ribonucleic protein (RNP) antibodies
Ribonucleic protein (RNP) antibodies are not specific for Systemic Lupus Erythematosus (SLE). In addition, Anti-Sjögren's syndrome antigen A (SSA, or Ro) and anti-Sjögren syndrome antigen B (SSB, or La) antibodies and histone antibodies are not specific for SLE. Anti-ribosomal P (anti-P) is associated with neurolupus but not particularly useful in management or diagnosis of neuropsychiatric lupus. Chromatin antibodies detection is of primary use in the diagnosis of drug-induced lupus not SLE. The initial laboratory results demonstrated a positive ANA test, or anti-nuclear antibody, which is a screening test for Lupus erythrematosus; an RA test, or rheumatoid factor, screening assay for the presence of an antibody linked with rheumatoid arthritis and other conditions, such as lupus erythematosus. Renal disease in patients with Systemic Lupus Erythematosus is indicated by an assessment of the levels of C3 and C4. In this case, there was a decreased level. A decrease in complement proteins indicates that the classic complement pathway may have been activated resulting in immune complexes, a clinically significant indication of tissue damage, particularly renal disease. Patients with SLE are characterized by the presence of antibodies to multiple antigens but some of these antibodies are not exclusive to SLE. An extractable nuclear antibody, Smith (Sm) antibody, is highly specific for SLE, but occurs in only 20-30 or35% of cases. Double-stranded DNA (dsDNA) antibodies (titer >1:10) detected by immunofluorescence assay (IFA) is seen in up to 50-60% of patients with Systemic Lupus Erythematosus (SLE). These antibodies indicate an active disease.
A Staphylococcus species recovered from a blood culture was found to produce acid from sucrose and maltose and showed alkaline phosphatase activity. The Staphylococcus was also coagulase negative. The same organism was also found in a culture from the central line tip. The most likely identification is: The correct answer is highlighted below Staphylococcus saprophyticus Staphylococcus schleiferi Staphylococcus epidermidis Staphylococcus aureus
Staphylococcus epidermidis is a normal flora organism on the skin, but a common cause of infections from medical devices. The organism can produce biofilms on catheters and other medical devices. The biofilm is a complex interaction between the device, host, and bacteria. A large number of organisms may aggregate in the biofilm and then be shed into the bloodstream or other nearby sites depending on the biofilm placement. Sometimes in blood cultures, Staphylococcus epidermidis can be seen as a contaminant from the skin during collection. However, by the organism presence in both the blood and line cultures, this can be determined as an infection from the central line. S. epidermidis also produces acid from sucrose and maltose and has alkaline phosphatase activity, important characteristics included in most algorithms and identification systems. They are also coagulase negative. Staphylococcus saprophyticus is coagulase negative, and does produce acid from sucrose and maltose, but is alkaline phosphatase negative. These organisms are laso typically found in the urinary system as a cause of urinary tract infections, specifically in women, and rarely found on the skin or mucous membranes. Staphylococcus schleiferi is also coagulase negative Staphylococcus but it does not produce acid from sucrose and maltose. It is alkaline phosphatase positive. These organisms are also typically considered contaminants or causes of opportunistic infections. Staphylococcus aureus is a coagulase positive Staphylococcus and would be eliminated based on that result alone. S. aureus however, is alkaline phosphatase positive as well as produces acid from sucrose and maltose.
Which is in the correct order from the lowest concentration of H antigen to the highest concentration of H antigen? The correct answer is highlighted below Bombay, A1B, A1, A2B, B, A2, O A1, O, B, A2, Bombay, A1B, A2B Bombay, O, A1B, A2, A1, B, A2B A1B, A2B, A2, O, B, A1, Bombay
The H antigen is an essential precursor to the ABO blood group antigens. Individuals with the rare Bombay phenotype (hh) do not express antigen H on their red blood cells; therefore, this type would contain the least amount of H antigen. Those which are type A1B would then have the second to least amount of H antigen since the precursor H antigens have been formed into A1 and B antigens instead. The remaining order of the H concentration from lowest to highest in the blood types given is: A1, A2B, B, A2, and O. O patients produce the most H antigen since they do not convert the H antigen into A or B antigens on their cell surface.
What must be true for the antiglobulin phase of the serologic crossmatch to be omitted (i.e., immediate spin crossmatch is done)? The correct answer is highlighted below The antibody screen must be negative and there is not history of detection of unexpected antibodies. The patient has not been transfused within the past 24 hours. The blood is needed for surgery. There is a history of detection of unexpected antibodies but the current antibody screen is negative.
The antiglobulin test may be omitted from the serological crossmatch if the patient's antibody screen is negative and there is no history of detection of unexpected antibodies. The transfusion history of the patient does not determine the type of crossmatch required for RBC transfusion. Patients scheduled for surgery should have a type and crossmatch complete prior to surgery. Patients with a history of antibodies, whether currently detectable or not, should have antiglobulin crossmatches.
A patient presents with fatigue. The CBC results are as seen below: Parameter Value Reference Interval White blood cells (WBC) 5.7 x 109/L 4.0-10.0 x 109/L Red blood cells (RBC) 4.0 x 1012/L 4.2-5.9 x 1012/L Hemoglobin 12.9 g/dL 12-16 g/dL Hematocrit 34% 37-48% MCV 85 fL 80-100 fL MCHC 38 g/dL 30-37 g/dL Considering all of the above information and the cells indicated by the arrows that were observed on the peripheral smear, what is the probable mechanism for the anemia that the patient is experiencing?
The cells indicated by the arrows are spherocytes. They are the result of a red cell membrane defect. This is an intracorpuscular defect that results in increased destruction. The RBC count is slightly below the reference range indicating that there is not a significant decrease in the production of RBCs. The information in the case history does not suggest a sudden blood loss. Extracorpuscular causes of hemolytic anemia can be from mechanical destruction by faulty heart valves or disseminated intravascular coagulation (DIC). In addition to spherocytes, fragmented red cells (schistocytes), are present.
A potential apheresis platelet donor must be deferred for how long following the use of aspirin? The correct answer is highlighted below 4 weeks 2 weeks 48 hours No deferral - can donate immediately given they meet all other requirements.
The correct answer is 48 hours. Because aspirin inhibits platelet function, a potential apheresis platelet donor must be deferred for a minimum of 48 hours after taking aspirin, as an apheresis unit of platelets is usually the sole source of platelets when transfused to a patient. 4 weeks is incorrect. Certain vaccinations may be cause for a 4 week deferral from donating whole blood and/or other blood products. 2 weeks is incorrect. The use of certain antiplatelet function medications such as clopidogrel and ticlopidine may be cause for a 2 week deferral from donating apheresis platelets. When donating a unit of whole blood, there is no restriction due to aspirin ingestion.
A 43-year-old female presented to her doctor for a routine check-up. Her only complaint was that she had been experiencing watery stools that occasionally contained pus and blood. Examination revealed tenderness in her abdomen. A stool for ova and parasite testing was sent to the laboratory and two suspicious forms were seen. The oblong form on the left measured 53 µm by 60 µm whereas the rounder form measured 45 µm by 37 µm. The parasite is MOST likely:
The correct answer is Balantidium coli. This patient has most likely contracted balantidiasis by ingesting water and/or food contaminated with the infective cysts. B. coli produces a large cyst and trophozoite entirely covered in cilia. Both stages are also known to contain a kidney-bean shaped macronucleus and a small, round micronucleus. Entamoeba histolytica, Dientamoeba fragilis, and Trichomonas vaginalis are much smaller than the measurements given and do not have a large, kidney-bean shaped macronucleus.
Which parasite listed below causes African Sleeping Sickness? The correct answer is highlighted below Onchocerca volvulus Leishmania donovani Leishmania braziliensis Trypanosoma gambiense
The correct answer is Trypanosoma gambiense. Trypanosoma gambiense often progresses to a chronic infection characterized by neurologic deterioration, often called a "sleeping sickness". Onchocerca volvulus infects the eye and is responsible for river blindness. Leishmania donovani and Leishmania braziliensis are responsible for cutaneous, mucocutaneous, and visceral lesions that are generally termed as Leishmaniasis.
You answered the question correctly. Which one of these physical exam results would cause a donor to be deferred? The correct answer is highlighted below A hemoglobin of 13.0 g/dL. A pulse of 75 A diastolic blood pressure of 110 mm Hg A temperature of 99.3 ºF
The correct answer is a diastolic blood pressure of 110 mm Hg. Donors must have a diastolic blood pressure must be less than 100 mm Hg. Donors must have a hemoglobin greater than or equal to 12.5 g/dL. Donors must have a pulse between 50-100 beats per minute. Donors must have a temperature at or below 37.5°C (99.5°F).
What is the mechanism of heparin-induced thrombocytopenia (HIT)? The correct answer is highlighted below Antibodies directed against platelet factor 4 (PF-4) and heparin complex. Administration of toxic doses of heparin that destroy platelets. Abrupt cessation of heparin therapy. Purposeful destruction of platelets by heparin administration.
The correct answer is antibodies directed against platelet factor 4 (PF-4) and heparin complex. HIT is a complication that may occur in some patients receiving heparin therapy. When heparin is administered to these patients, it forms an immune complex with platelet factor 4 (PF-4) that is released from the alpha granules in platelets. The body's immune system recognizes this complex as a foreign substance and forms an antibody against it. The antibody binds to this complex and the platelets are destroyed. HIT is not the result of administration of toxic doses of heparin. The dosing is correct; the thrombocytopenia is the result of the patient's immune response to the heparin. Abrupt cessation of heparin therapy will not cause thrombocytopenia. If a patient is diagnosed with HIT, heparin therapy should be stopped immediately and replaced with a different anticoagulant therapy if necessary. The mechanism by which heparin prevents clotting is not due to platelet destruction.
One risk associated with patients that require chronic transfusions is: The correct answer is highlighted below Iron overload Fear of needles Transfusion associated graft-versus-host disease (TA-GVHD) Increased antigen production
The correct answer is iron overload. A long-term complication of RBC transfusion is iron overload. Each unit of red cells contains 225 mg of iron, which puts these patients at risk for iron overload. Fear of needles is not induced by chronic transfusions. TA-GVHD is a rare complication that is more likely in certain populations, but not associated with patients that receive chronic transfusions. Increased antigen production is not something that can be associated with chronic transfusions, but increased antibody production would be.
Albumin levels are can be a good gauge for chronic protein deficiency. Which of the following terms describes inadequate protein and caloric intake? The correct answer is highlighted below Kwashiorkor Marasmus Albuminemia Hypoproteinism
The correct answer is marasmus. Marasmus is a nutritional disease as a result of calorie deprivation. This includes an insufficient amount of protein. Kwashiorkor is a nutritional disease resulting from protein deprivation. In some cases caloric intake can be adequate or even excessive. Albuminemia is not a term that is commonly used. It would only point to album and not other proteins and would not describe an insufficient caloric intake. Hypoproteinism is not a term that is used. Hypoproteinemia is a term that can be used to describe low levels of protein in the blood, but would not necessarily be used to describe a low caloric intake.
Why is Weak D testing not performed on pregnant women? The correct answer is highlighted below Weak D testing should be performed on pregnant women. Weak D testing is not required as part of a prenatal evaluation, as it is not possible to differentiate weak D from partial D serologically. Weak D testing is no longer used in blood banking. Weak D testing is not reliable in pregnant women.
The correct answer is weak D testing is not required as part of a prenatal evaluation, as it is not possible to differentiate weak D from partial D serologically. Weak D testing is still used in blood banking, especially in donor testing. Weak D testing is reliable in all patients with a negative DAT.
The use of the direct antiglobulin test is indicated in all the following EXCEPT: The correct answer is highlighted below Transfusion reactions Autoimmune hemolytic anemia Hemolytic disease of the newborn 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 primary mechanism responsible for glomerular filtration is: The correct answer is highlighted below Osmotic gradient Concentration of blood components Rate of blood flow through the kidneys Hydrostatic differential in glomerular tufts
The hydrostatic pressure in the capillaries of the glomerular tuft drives the filtrate across their semipermeable membrane. The normal glomerular filtrate is similar in composition to the plasma, with the exception that molecules with a molecular weight of greater than about 70,000 daltons are not filtered.
What are the MAIN functions of the distal convoluted tubules? The correct answer is highlighted below Balance hydrogen ions and keep the body pH at 6.8 Control aldosterone production and ammonia reabsorption Excrete various antibiotics and uric acid Maintain water-electrolyte and acid-base balances
The main functions of the distal convoluted tubules are to maintain water-electrolyte and acid-base balances. These functions are controlled by antidiuretic hormone (ADH) and aldosterone.
The most frequently encountered immunoglobulin demonstrated in patients with Multiple Myeloma is: The correct answer is highlighted below IgM Ig G Ig A IgE
The most commonly encountered form of immunoglobin in patient suffering from Multiple Myeloma is Ig G at 52%. Four subtypes of IgG heavy chains are known to exist among patients with IgG myeloma (IgG1, IgG2, IgG3, IgG4). The subclasses of cases of IgG myeloma are distributed as follows: 65% gamma G1, 23%IgG2, 8% IgG3, 4% IgG IgM occurs in 12% of patients with Multiple Myeloma. Ig A occurs in 22% of patients with Multiple Myeloma. IgE is rarely detected in patients with Multiple Myeloma.
What is the shelf-life of whole blood collected in CPDA-1? The correct answer is highlighted below 21 days 28 days 35 days 48 days
Whole blood collected with CPDA-1, or citrate-phosphate-dextrose-adenine, has a storage (shelf) life of 35 days from the date of collection. Whole blood collected with CPD (citrate-phosphate-dextrose), CP2D (citrate-phosphate-dextrose-dextrose), or ACD (acid-citrate-dextrose) has a storage (shelf) life of 21 days from the date of collection.
Whole blood or red blood cell units will be shipped from the American Red Cross to the transfusion facility. At what temperature should the units be kept during transportation? The correct answer is highlighted below 1-4 °C 1-10 °C 2-6 °C 2-8 °C
Whole blood or red blood cell units must be maintained between 1 and 10 °C during transportation. Blood in storage should be kept between 1 and 6 °C. All other answer choices have temperature ranges that are too restrictive.