ASCP Exam 1
In heme synthesis, how many molecules of delta-aminolevulinic acid (ALA) are needed to form one molecule of heme? A- 2 B- 4 C- 6 D- 8
D- 8 The correct answer is 8 molecules of ALA are needed to form 1 molecule of hemoglobin.
The laboratory workplace includes many hours of computer use. The suggested time for a break after 30 minutes of computer use is: A- 1-2 min B- 3-5 min C- 5-10 min D- 20 min
A- 1-2 min It is suggested that after 30 minutes of computer use, a 1 to 2-minute break will provide the eyes a break to avoid fatigue. After each hour, an employee should take a 5 to 10-minute break
Given the following information, calculate the results in mg/24 hrs for a 24-hour urine protein. Total volume for 24 hours = 2,400 mL Urine protein = 2.7 mg/dL A- 64.8 mg/ 24hrs B- 10.87 mg/24hrs C- 57.5 mg/24hrs D- 5.89 mg/24hrs
A- 64.8 mg/ 24hrs 2.7 mg/dL X 2400 mL/24 hr X 1 dL/100 mL = 2.7 mg X 2400/100 = 64.8 mg/24 hr
C-reactive protein (CRP) is often used as a marker of inflammation. However, it has a low _________. A- Sensitivity B- Specificity C- Accuracy D- Precision
B- Specificity CRP is one of the first acute-phase proteins to rise as a result of inflammatory disease and is produced by the liver. CRP is a sensitive marker of inflammation, however, it has low specificity, meaning that is not indicative of the absence of inflammation. Accuracy and precision are terms used in test method evaluation.
Which property of solutes listed below determines the direction of migration (which electrode the solutes migrate to) in routine serum electrophoresis? A- Size B- Charge C- Shape D- Strength of electric field
B- Charge The charge on a solute determines the direction of that solute's migration. Positive ions (cations) will migrate to the cathode, the negative electrode. Negative ions (anions) will migrate to the anode, the positive electrode. The velocity of migration is controlled by the net charge of the particle, the size and shape of the particle, the strength of the electric field, chemical and physical properties of the supporting medium, and the electrophoretic temperature.
Varied red blood cell morphologies due to pitting, culling, filtering, and the persistence of abnormal red blood cells in the peripheral blood is most likely due to what? A- Cirrhosis of the liver B- Splenectomey C- Incompatiable blood tranfusion D- Autosomal recessive trait
B- Splenectomey After a patient has their spleen (splenectomy) removed, their red blood cells will no longer be filtered in the same manner. The spleen acts to remove abnormally shaped red blood cells as well as red blood cells containing inclusions. Without the spleen, the liver can perform some of the filtering; however, not to the same degree as the spleen. Therefore, without the spleen, abnormal red blood cells are able to persist in the peripheral blood. The liver's major functions are producing digestive enzymes and filtering toxins out of the blood, not filtering abnormal blood cells. If a patient were to be given incompatible blood their body would have an autoimmune reaction causing the destruction of the foreign red blood cells. There isn't an autosomal recessive trait that causes varying red blood cell morphologies.
The ultimate end product of both epinephrine and norepinephrine metabolism is: A- Metanephrine B- Vanillylmandellic acid (VMA) C- Homovanillic acid (HVA) D- Cortisol
B- Vanillylmandellic acid (VMA) Vanillylmandelic acid (VMA) is a metabolite of the catecholamines epinephrine and norepinephrine. VMA is found in the urine, along with other catecholamine metabolites, including homovanillic acid (HVA), metanephrine, and normetanephrine. Urinary VMA is elevated in patients with tumors that secrete catecholamines.
The serum from a patient of African-American descent is reactive with all screening and panel cells. Which antibody directed to a high incidence antigen is most likely to be present? A- Anti- Lu^b B- Anti- Jk3 C- Anti- U D- Anti- Ku
C- Anti- U The U antigen is located on glycophorin B, a glycoprotein that carries the S, s, and U antigens in the MNS blood group system. Individuals who are U-negative are also S-s- and are of black descent. This phenotype is never found in the white population. The U antigen is present in more than 99% of the population. Anti-Lub is rarely seen because of the high prevalence of the antigen. The presence of anti-Lub is not associated with a specific ethnicity. Individuals who are Jk(a-b-) can make anti-Jk3. The Jk(a-b-) phenotype is most commonly seen in individuals of Polynesian, Filipino, or Chinese descent. Anti-Ku may be found in immunized individuals who have the Kell null (K0) phenotype. The K0 phenotype is not associated with a specific ethnicity.
A technologist decides to make a 1:20 dilution of cerebrospinal fluid (CSF) after briefly evaluating a portion of the sample microscopically. After making the dilution and charging the chambers, the number of observed cells in each of the large squares of the hemocytometer is >100. What should the technologist do to obtain the most accurate count? A- Count all four corner squares. B- Make a smaller dilution. C- Make a larger dilution. D- No dilution is necessary.
C- Make a larger dilution. The best choice would be to make a larger dilution before performing the cell count. This will provide the most accurate results.
In HbSS blood, an increased amount of which of the following surface antigens on young sickle cells (reticulocytes) may allow platelets to form a bridge between the reticulocytes and endothelial cells, ultimately leading to vaso-occlusion? A- CD3 B- CD4 C- CD8 D- CD36
D- CD36 HbSS blood may contain reticulocytes with an abnormal presence of CD36 on their membranes, allowing platelets to form a bridge between these young sickle cells and endothelial cells in post-capillary venules. This initial slow down of blood flow creates an environment in which cells containing HbSS can easily form sickled cells and cause vaso-occlusion. CD3, CD4, and CD8 are all associated with T-lymphocytes.
A specimen drawn from an indwelling catheter that was contaminated by heparin would be indicated by: A- Normal PT and aPTT B- Prolonged PT and normal aPTT results C- Prolonged aPTT and prolonged reptilase time test D- Prolonged aPTT and normal reptilase time test
D- Prolonged aPTT and normal reptilase time test Heparin contamination is characterized by an elevation in the aPTT test and can also cause an increased PT test as well. Reptilase time tests are used to eliminate the effects of heparin contamination as the reagents and method are resistant to the effects of antithrombin III, unlike the PT and aPTT tests. Therefore, it would be expected that a patient sample containing pre-analytical heparin contamination will show an increased aPTT (and sometimes PT as well) while showing a normal reptilase time.
Which testing method is appropriate for identifying specific allergens? A- Complement fixation B- C- reactive proteins C- Radioimmunoassay (RIA) D- Radioallergosorbent tests (RAST)
D- Radioallergosorbent tests (RAST) Radioallergosorbent tests (RAST) is a procedure that detects the presence of IgE (and IgG) antibodies to allergens; a method used to measure antigen-specific IgE by means of a noncompetitive solid-phase immunoassay. Complement fixation is a traditional procedure that detects the presence of a specific antigen-antibody reaction by causing in vitro activation of complement. If complement is not fixed, lysis of the preantibody-coated reagent erythrocytes (RBCs) occurs. The acute-phase protein, CRP, is used clinically for monitoring infection, autoimmune disorders, and, more recently, healing after myocardial infarction. Radioimmunoassay (RIA) is an older and less frequently used laboratory technique that uses radioactive substances to evaluate immunoglobulins. Traditional RIA is done with specific antibodies in a liquid solution. Solid-phase RIA uses antibody-bound to a solid support, e.g. glass beads.
The serum of which of the following individuals may agglutinate group A1 cells? A- A2 individual B- A1B individual C- A1 individual D- Newborn
A- A2 individual Approximately 4% of individuals with A2 blood type will have Anti-A1 antibodies in their serum. Individuals with some rarer A subgroups may also have Anti-A1 in their serum. Agglutination will occur if the serum from any of these individuals is mixed with A1 red cells. An A1B or an A1 individual would not be expected to produce anti-A1. A newborn would not typically have yet formed any naturally occurring ABO antibodies.
Atherosclerosis is due to which of the following? A- Build up of plaque B- Aggregation of platelets C- Hypercalcemia D- Hypocalcemia
A- Build up of plaque Atherosclerosis is due to the build-up of plaque over a number of years. The risk to patients with significant atherosclerosis is that eventually, a narrowing of the artery (stenosis) can cause a reduction in oxygen delivery to tissues, and plaque rupture can lead to an acute coronary event. Aggregation of platelets and hypercalcemia or hypocalcemia are not the reasons for atherosclerosis formation.
A 40-year-old man patient presents with non-specific physical complaints which include abdominal pain. Based on symptoms and family history the physician suspects Hereditary Hemochromatosis. Which of the following laboratory tests would be the LEAST diagnostic? A- CBC B- Liver function test C- Genetic studies D- Iron studies
A- CBC The purpose of laboratory testing for suspected hereditary hemochromatosis is to screen for the condition (iron studies), diagnose the cause and degree of organ damage (liver function test), pinpoint the mutation (genetic testing), and monitor treatment. Although the CBC may be an effective screening test for many conditions and would most likely be a part of routine screening, it would have little effect on the diagnosis of hemochromatosis.
Which antibody identified in prenatal specimens is never a cause of hemolytic disease of the fetus and newborn? A- Anti-D B- Anti-c C- Anti-E D- Anti- I
D- Anti- I Anti-I is a common autoantibody that can be found in virtually all sera. It is benign (not associated with in vivo red blood cell destruction). It is usually a weak, naturally occurring, saline-reactive IgM agglutinin. Rh antibodies are primarily IgG and Rh antigens are well developed early in fetal life. While the D antigen is the most immunogenic, c antigen is the next most likely Rh antigen to elicit an immune response, followed by E, C, and e. Rh antibodies formed by the Rh negative pregnant women coat the fetal red blood cells that carry the corresponding antigens. The coated fetal cells are removed from the fetal circulation (hemolytic disease of the fetus and newborn).
This member of the Enterobacteriaceae was isolated from a stool specimen and gave the following biochemical reactions: TSI: K/A, no gas, no H2S Citrate: Positive Lysine decarboxylase: Negative Ornithine decarboxylase: Positive Indole: Negative This organism agglutinated in Group D Shigella antiserum. All of the above biochemical results are consistent with this identification, EXCEPT? A- TSI B- Citrate C- Lysine D- Indole
B- Citrate Citrate is the correct answer. Shigella species are all citrate negative. The other three results are all consistent with an identification of Shigella sonnei.
Fresh frozen plasma should be used for which of the following? A- Platelet replacement B- Coagulation deficiencies C- Volume replacement D- Albumin replacement
B- Coagulation deficiencies FFP, or fresh frozen plasma, should be used to treat coagulation deficiencies, although the levels of factors V and VIII are usually decreased in FFP units. FFP is not used for platelet replacement as there are virtually no platelets in FFP units. FFP should never be used as a volume expander unless traumatic bleeding is taking place. Finally, FFP is not used to replace albumin in recipients.
The egg is the infective stage of this parasite for humans. What is the identification of this organism? A- Enterobius vermicularis B- Taenia solium C- Trypanosoma cruzi D- Schistosoma mansoni
A- Enterobius vermicularis Enterobius vermicularis (also known as Pinworm) infects humans after ingestion of eggs. The eggs migrate to the digestive tract, to the small intestine, where they hatch and release larvae. Although Schistosoma mansoni and Taenia solium have eggs in their corresponding life cycles, this form is not the infective stage for human infections. Taenia solium infects humans after ingestion of pork contaminated with cysticercus larva. This larva consists of a scolex surrounded by a thin-walled cyst filled with fluid. The larvae will emerge in the small intestine, mature, and release eggs. Those eggs are consumed by the animal species (pig), in which the larva will deposit in the tissues. Trypanosmoa cruzi does not have an egg stage at all. T. cruzi is a hemoflagellate and requires an arthropod vector (the reduviid bug) for transmission. When the bug bites a human, infective trypomastigotes are deposited next to the bite. Humans will scratch the bite and rub these into the area and into the host. Schistosoma mansoni infection occurs through the water-residing cercaria, which enters the human body by drilling into the skin. They migrate to the bloodstream where they mature and reside in the veins surrounding the intestinal tract. The females lay eggs. The eggs reach water and release the miracidium that must find a snail host to develop into cercaria. The egg is not the infective form for humans
Increased concentrations of alpha-fetoprotein (AFP) in adults are MOST characteristically associated with: A- Hepatocellular carcinoma B- Alcoholic cirrhosis C- Chronic active hepatitis D- Multiple myeloma
A- Hepatocellular carcinoma Alpha-fetoprotein is a substance typically used in the triple test during pregnancy and for screening chronic liver disease patients for hepatocellular carcinoma. 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 are usually associated with hepatocellular carcinoma, as it is a tumor marker in this population. Alcoholic cirrhosis, chronic active hepatitis, and multiple myeloma would not cause an increase in serum AFP.
The majority of Lewis antibodies are of which immunoglobulin class? A- IgM B- IgG C- IgA D- IgE
A- IgM Lewis antibodies are often naturally occurring and they occur without red blood cell stimulus. They are generally IgM and do not cross the placenta. Anti-Lea is the most commonly encountered of the Lewis antibodies.
Which term listed below refers to the process that must be followed when notification is received that a donor of a unit transfused now tests positive for an infectious disease? A- Look back B- Donor notification C- Minor crossmatch D- Major crossmatch
A- Look back The "look-back" process involves the donation facility looking back at previous donations to identify recipients who received a blood product from a donor that is newly testing positive for an infectious disease. The time frame for "look-backs" vary by infectious disease. The goal is to identify recipients who were at risk of receiving an infectious blood product before the donor was testing positive for a particular infectious disease (ex. HIV). Donor notification includes regulations for notification of donors that they currently test positive for an infectious disease. Minor crossmatch involves testing donor serum and recipient red blood cells for compatibility. Major crossmatch involves testing donor red blood cells and recipient serum for compatibility.
The following results correlate with which of the following myelodysplastic syndromes? 2 cyotpenias in the peripheral blood 11% blasts in the peripheral blood 18% blasts in the bone marrow Auer rods present A- MDS-EB-2 B- MDS-SLD C- MDS-MLD D- MDS-U
A- MDS-EB-2 These results are consistent with Myelodysplastic Syndrome (MDS) with excess blasts subtype 2 (MDS-EB-2). In the peripheral blood of a case of MDS-EB2 you would expect to see 1-3 cytopenias and between 5 and 19% blasts. In the bone marrow of cases of MDS-EB2, you would expect to see 0 to 3 dysplastic lineages and between 10 and 19% blasts. Patients with Auer rods are classified as MDS-EB-2. MDS with single lineage dysplasia (MDS-SLD) have no or rare blasts in their peripheral blood with less than 5% blasts in the bone marrow. MDS with multilineage dysplasia (MDS-MLD) and MDS, unclassified (MDS-U) present with no or rare (<1%) blasts in the peripheral blood.
All of the following conditions would be associated with an increased level of alpha-fetoprotein, EXCEPT? A- Prostate Cancer B- Hepatocellular Carcinoma C-Viral Hepatitis D- Testicular Tumors
A- Prostate Cancer AFP is not found in increased levels in patients with prostate cancer. PSA, or prostate-specific antigen, is commonly used to screen for prostate cancer, not AFP. Hepatocellular carcinoma, viral hepatitis, testicular tumors, and pancreatic cancer are all associated with increased levels of AFP. In addition, liver cirrhosis and gastric cancers can also have an associated increased AFP level. AFP is one of the oncofetal proteins which are produced in high concentration during fetal life. The fetal yolk sac and liver produce AFP. Oncofetal proteins usually disappear or are reduced to very low concentrations after birth. Increased alpha-fetoprotein levels in adults are usually associated with hepatocellular carcinoma, a tumor marker in this population.
A day-care outbreak of diarrhea revealed an oxidase-negative, non-lactose fermenting, nonmotile, gram-negative rod. These characteristics presumptively indicate which organism? A- Shigella sp B- Salmonella sp C- E. coli 0517:H7 D- Campylobacter jejuni
A- Shigella sp Shigella is associated with each of the characteristics in this question. Salmonella matches each of the characteristics EXCEPT the motility, as they are predominantly motile and have flagella. E.coli 0157:H7 cannot be the correct choice as it does ferment lactose. Campylobacter jejuni is oxidase positive and grows in a microaerobic environment at 42°C.
Whipworm infection is typically diagnosed by the microscopic observation of adult worms or barrel-shaped eggs with polar plugs in stool specimens. What organism is known as the whipworm? A- Trichuris trichiura B- Ascaris lumbricoides C- Necator americanus D- Enterobius vermicularis
A- Trichuris trichiura Whipworm infection, or trichuriasis, is caused by Trichuris trichiura. It is a soil-transmitted parasite. Eggs are brown, barrel-shaped, and have a polar plug at each end. Heavy infections may lead to rectal prolapse. Necator americanus (hookworm), and Ascaris lumbricoides are also soil-transmitted. Necator americanus eggs are oval, and usually contain the 4 to 8-cell stage when observed. However, N. americanus eggs and rhabditiform larva are indistinguishable from Ancylostoma duodenale, and are reported as "hookworm." Ascaris lumbricoides eggs are oval, with a thick wall, and often have a brown, mammillated outer layer. Enterobius vermicularis is another roundworm, known as the pinworm. Eggs may be spread in the environment. The eggs are colorless, oval, and slightly flattened on one side. Whipworm, hookworm, pinworm, and Ascaris have a worldwide distribution.
What type of specimen is used for testing cyclosporine levels? A- Whole blood B- Serum C- Plasma D- Urine
A- whole blood The majority of cyclosporine is sequestered in circulating erythrocytes. As plasma is separated from the cellular component, the temperature of the sample changes reducing the level of cyclosporine, which causes an inappropriate reading of cyclosporine levels. Serum, plasma, and urine are not used for monitoring therapeutic levels due to this.
How does Aspirin (salicylic acid) affect platelet function? A-Inhibiting cyclooxygenase B-Activates lipids C- Inhibiting carbohydrates D- Activating nucleic acid
A-Inhibiting cyclooxygenase Aspirin, or acetylsalicylic acid, acts as an antithrombotic agent due to inhibition of platelet function by acetylation of the platelet cyclooxygenase, also known as COX. This prevents arachidonic acid from catalyzing the reaction that allows for normal coagulation, which results in an irreversible inhibition of platelet-dependent thromboxane formation. Aspirin has no effect on inhibiting lipids for platelet function. Aspirin has no effect on inhibiting carbohydrates for platelet function. Aspirin does not activate nucleic acids for platelet function because platelets lack a nucleus.
The growth of yellow-white yeast colonies with a smooth or hair-like surface within 2 - 3 days on non-selective culture media generally requires further procedures to make a presumptive identification. Microscopic observation of the subculture of colonies growing on cornmeal agar is one such approach, as illustrated in the photomicrograph. Note the "logs in-stream" arrangement of elongated blastoconidia. From the multiple choices, select the name of the presumptive yeast identification. A- Candida krusei B- Candida kefyr C- Canldida glabrata D- Candida parapsilosis
B- Candida kefyr Candida kefyr is the correct response. Characteristic is the abundant production of elongated, rectangular blastoconidia that arrange in distinct loose-like clusters simulating the appearance of "logs in a stream". Recovery in laboratory cultures usually indicates a contaminant, although clinical correlation may be required in some cases as infections. C. kefyr have been identified particularly in patients who have received broad-spectrum antibiotics or who are immune-suppressed and has been isolated from blood, respiratory secretions, skin and urine Canldida glabrata produces uniform, small, spherical cells arranged in relatively tight clusters rather than as elongated blastoconidia arrangement. The identification can be confirmed by demonstrating the assimilation of both glucose and trehalose. C. glabrata among the species of yeasts is a common isolate from urinary tract infections Candida parapsilosis produce delicate radiating conidiophores from which tiny conidia are arranged in a pattern colloquially referred to as "sagebrush" or "cross matchstick". Rectangular blastoconidia arranged in a "logs in stream" pattern are not observed Candida krusei colonies in maturity consist of blastoconidia that grow in short branches from the mycelium, with the production of elongated cells in a treelike or crossed matchstick arrangement rather than as "logs in stream".
An elevated level of which of the following hormones will inhibit pituitary secretion of adrenocorticotropic hormone (ACTH)? A- Aldosterone B- Cortisol C- Testosterone D- Progesterone
B- Cortisol Cortisol is part of the negative feedback mechanism for ACTH. So, elevated levels of cortisol stimulate the pituitary gland to inhibit the secretion of ACTH. The hypothalamic-pituitary-end organ negative feedback system that controls cortisol release follows the steps: -Hypothalamus releases corticotropin-releasing hormone (CRH) which is delivered to the anterior pituitary. -CRH triggers the release of ACTH by the anterior pituitary. Antidiuretic hormone (ADH) and pro-inflammatory cytokines can also independently trigger ACTH release. - ACTH triggers the synthesis and release of cortisol from the adrenal glands. -Increased cortisol levels feedback at the anterior pituitary (to stop ACTH release) and hypothalamus (to stop CRH) respectively. Hypothalamus is the major site of this negative feedback from cortisol.
The antigen marker most closely associated with transmission of HBV infections is: A- HBsAg B- HBeAg C- HBcAg D- HBiAg
B- HBeAg The presence of HBeAg connotes active replication of hepatitis B virus, with a high degree of infectivity. HBsAg is the first marker to appear in HBV infection and indicates active infection. It is an important marker in detecting initial infection and is a required donor test HBcAg is tested to determine the course of HBV infections. HBiAg is not an actual component of HBV, nor is it tested for to determine the course of HBV infection.
Which finding best distinguishes immune hemolytic anemia from other hemolytic anemias? A- Rouleaux B- Positive DAT C- Splenomegaly D- Increased erythrocyte count
B- Positive DAT In the group of disorders referred to as immune hemolytic anemias, erythrocytes are destroyed too early by an immune-mediated process that results from antibodies, complement, or both attaching to the red cell membrane. The presence of immune hemolytic anemia is confirmed by a positive DAT (direct antiglobulin test). Rouleaux is the formation of red cells that are stacked and appear like a stack of coins. This is a characteristic finding in multiple myeloma. Splenomegaly, or an enlarged spleen, may be found in Gaucher's disease or in polycythemia vera. It is not found in immune hemolytic anemia. Increased erythrocyte count is not a finding in immune hemolytic anemia.
Which of the following would be considered most significant as it relates to serological testing: A- Presence of an antibody titer is generally diagnostic B- Rise of antibody titers is diagnostic C- Concentration of antibody is diagnostic D- Cross reactivity is not significant
B- Rise of antibody titers is diagnostic Serological diagnosis of active or recent infection generally requires the demonstration of IgM antibody, or the demonstration of a fourfold rise in the titer of specific IgG antibody.
Which of the following conditions would argue in favor of therapeutic drug monitoring (TDM) for a given drug? A- The drug has a low degree of protein binding. B- The drug is given chronically. C- The drug has low toxicity and few side effects. D- The effective and toxic concentrations are not well defined.
B- The drug is given chronically. Drugs that are given chronically are usually monitored by TDM. Drugs that are highly protein-bound are good candidates for TDM since changes in plasma binding proteins can affect drug levels. A drug that has low toxicity and rare side effects will probably not need TDM. If the effective concentration and toxic concentrations are not well-defined, TDM will not be useful because there is no reference for comparison.
The light blue-gray inclusions observed in the cytoplasm of many of the bands and segmented neutrophils of a burn patient are most likely? A- auer rods B- dohle bodies C- toxic granules D- May-Heglgin bodies
B- dohle bodies The correct answer here is Dohle bodies. Dohle bodies are associated with the peripheral smears of burn patients, severe infections, and cancer as a result of toxic drugs used on the patients. Auer rods are found in myeloblasts, not bands or neutrophils. Toxic granules can be found in many conditions, especially infections. Toxic granules have a stippling appearance, which does not have the appearance as described in the question. May-Hegglin bodies are found in May-Hegglin anomaly, which is a white cell disorder. May-Hegglin bodies are very similar in appearance to Dohle bodies.
A tech is reviewing a Gram stain from a positive blood culture bottle. The background on the stain shows pink debris and the tech thinks that there is also Gram-negative bacilli but is having difficulty differentiating the artifact and possible organisms. What could the tech do next to help determine if bacteria are present in the blood culture bottle? A- stain with Wright-Giemsa B- stain with Acridine orange C- stain with calcofluor white D- stain with periodic acid-schiff
B- stain with Acridine orange Acridine orange is a fluorescent stain used in microbiology to determine bacteria in direct smears of biological fluids. It is very helpful in cases of fluids with low bacterial numbers suspected (such as CSF) and to differentiate bacteria from debris on slides. The stains detect both living and dead bacteria. A Gram stain will still have to be performed in order to differentiate Gram-positive and Gram-negative organisms.
The first time a cell containing HbSS is deoxygenated, it forms a sickle cell. Upon reoxygenation, which of the following is true for the sickle cell? A- It will remain sickled B-It will return to a normal biconcave shape C- It will turn into a codocyte (target cell) D- It will appear as an echinocyte (burr cell).
B-It will return to a normal biconcave shape Initially, sickling is reversible. The red blood cell (RBC) can return to its normal biconcave shape. Upon repeated sickling and unsickling, cells with HbSS become irreversibly sickled. Repeated cycles of sickling cause the RBC membrane to become rigid. At this point, the sickle cell becomes irreversibly sickled, whether the hemoglobin is oxygenated or deoxygenated. Target cells (codocytes) appear as a target or bulls-eye. They can be found in a number of conditions, such as thalassemia, liver disease, hemoglobinopathies, and others. Burr cells (echinocytes) appear as spiculated with short, equally spaced projections around the entire surface of the cell. They can be found in liver disease, uremia, and other conditions.
How many standard deviations (SD) above and below the mean is accepted as being an appropriate control limit range on a control chart utilizing the Westgard rules: A- 1 SD B- 2 SD C- 3 SD D- 4 SD
C- 3 SD Three standard deviations (3 SD) are used to limit the potential for erroneous results and to identify any random or systemic errors that may occur in testing. However, additional Westgard rules are also used to identify errors that occur within the 3 SD range. These may be warning rules or mandatory rules and are intended to flag a potential issue before patient care is affected. For example, the 22s rule identifies if two consecutive points are more than 2 SD on the same side of the centerline. A laboratory that only accepts results 1 SD from the mean will lead to a false rejection of many quality control results as only 66.8% of samples tested are expected to fall within this range. Some Westgard rules flag quality control results that are 2 SD from the mean. However, a laboratory that only accepts results that are within 2 SD from the mean will have an increased rate of false rejections. Samples that are greater than 3 SD from the mean should never be accepted.
Given the following data, what is the most likely disease state? Total bili = 4.0 (0.5-1.5) Direct bili = 3.0 (0.2-0.5) AST = 75 (2-25) ALT = 118 (2-23) LD = 220 (< 140) ALP = 841 (28-68) GGT =150 (21-40 U) A- Intoxication B- Hemolytic disease C- Biliary duct obstruction D- Bone disease
C- Biliary duct obstruction The correct answer is biliary duct obstruction, as seen by the increase in ALP and GGT, both enzymes specific for biliary tree issues. In addition, the conjugated bilirubin is also increased, showing that bilirubin is getting to the liver for processing, but spilling over as it cannot be removed properly. In intoxication, there would not be an increase in bilirubin; in hemolytic disease, there would be an increase in unconjugated bilirubin and LD; in bone disease, there would be an increase in ALP but no increase in GGT or the other liver enzymes.
A urine production of less than 400 mL/day is: A- Consistent with normal renal function and water balance B- Termed isosthenuria C- Defined as oliguria D- Associated with diabetes mellitus
C- Defined as oliguria Oliguria is defined as the production of a decreased amount of urine. This can be defined as a daily urine production of less than 400 mL. Normal urine production is between 1,200 to 1,500 mL and it can range from 600 to 2,000 mL. Isostenuria is a condition that produces urine with a specific gravity of 1.010 due to impaired renal tubular function. Diabetes mellitus produces urine volumes of >2,500 mL/day.
In order to obtain an appropriate specimen before preparing a smear for acid-fast bacilli staining in a sputum sample, what must be done to the original sample? A- Mincing or grinding B- Concentraion and centrifugation C- Digestion and decontamination D- Nothing needs to be done
C- Digestion and decontamination The correct answer is digestion and decontamination. Digestion is necessary to liquefy the sample by removing proteinaceous material from samples that contain excess mucus, such as respiratory samples. Decontamination is necessary to kill all non-mycobacterial organisms in samples that contain abundant normal flora, such as respiratory samples. Mincing or grinding is necessary when examining tissue samples for the presence of acid-fast bacilli. Concentration and centrifugation may be necessary when attempting to identify acid-fast bacillus in large amounts of a sterile body fluid.
All of the following are known causes of aplastic anemia, EXCEPT? A- Viral infection B- Chemical agent C- Enzyme deficiencies D- Ionizing radiation
C- Enzyme deficiencies Aplastic anemia can be described as the condition of pancytopenia (all cell lines decreased) and is associated with a hypocellular (low number of cells) bone marrow. There are several possible causes of aplastic anemia. Certain drugs, chemical agents, ionizing radiation, viruses, and biological agents are just a few of the things that are known to cause acquired aplastic anemia. In many cases, aplastic anemia is idiopathic, meaning the cause is unknown. Enzyme deficiencies are usually associated with hemolytic anemias.
A dermatophyte that produces thin-walled, two or three-celled macroconidia in clusters, and no microconidia, most likely belongs to the genus: A- Microsporum B- Trichopytan C- Epidermophyton D- Ajellomyces
C- Epidermophyton Epidermophyton floccosum is the correct answer. One of the key characteristics in the identification of Epidermophyton floccosum is the inability of this dermatophyte to produce microconidia. Two to four-celled, club-shaped macroconidia are produced, usually in clusters of two or three. Both Microsporum species and Trichophyton species produce microconidia, the latter genus in profusion. The organism name, Ajellomyces dermatitidis is actually the same organism as Blastomyces dermatitidis, just a different form. The genus Blastomyces dermatitidis does not belong to the dermatophytes; rather it belongs to the group of fungi known as Systemic Mycoses. It produces an abundance of microconidia which are single, circular, and produced on short conidiophores that resemble lollipops.
The National Heart, Lung, and Blood Institute (NHLBI) and American Heart Association (AHA) have created a set of parameters to define the presence of metabolic syndrome. Select the set of laboratory assays that are utilized in the NHLBI and AHA criteria for metabolic syndrome diagnosis. A- LDL-C, triglycerides, HDL-C, and fasting blood glucose B- Fasting blood glucose, triglycerides, insulin, and VLDL C- Fasting blood glucose, triglycerides, HDL-C D- Fasting blood glucose, triglycerides, HDL-C, and VLDL
C- Fasting blood glucose, triglycerides, HDL-C Fasting blood glucose, triglycerides, HDL-C along with waist circumference and blood pressure are the measurements used in the NHLBI and AHA criteria. There are five basic parameters described below as metabolic risk factors. A patient must have at least three of the five risk factors to be diagnosed with metabolic syndrome. 1. A large waistline. In women, =35 in. (88 cm); in men, =40 in. (102 cm) 2. High triglyceride level, =150 mg/dL 3. High fasting blood glucose, =100 mg/dL 4. Low HDL cholesterol. In women, <50 mg/dL; in men, <40 mg/dL 5. High blood pressure, that is, =130/85 mm Hg
Patients with which of the following conditions would benefit most from washed red cells: A- Warm autoimmune hemolytic anemia B- Cold autoimmune hemolytic anemia C- IgA deficiency with anti-IgA D- Multiple red cell alloantibodies
C- IgA deficiency with anti-IgA Washing not only reduces the number of leukocytes and platelets that are often responsible for febrile reactions, but also eliminates plasma proteins, such as IgA. Warm autoimmune hemolytic anemia, cold autoimmune hemolytic anemia, and alloantibodies all involve patient antibody binding to antigens on the donor red blood cells. Washing would not remove the antigens from the red blood cells so washing has no advantage in these cases.
Nocardia species can be isolated from cutaneous specimens and can produce sulfur granules. These granules can be found in tissue specimens and can aid in detecting aerobic actinomycetes. To help identify the presence of sulfur granules in tissue specimens, which of the following methods will be most beneficial? A- Gram stain B- Acid fast stain C- KOH mount D- Gomori methenamine-Silver (GMS)
C- KOH mount KOH Mount is the correct answer because this is a rapid test that can detect sulfur granules in tissue. By performing a KOH mount on tissue specimens, proteinaceous material can be digested in order to detect the presence of sulfur granules. Aerobic actinomycetes, such as Actinomadura species, Nocardia species, and Streptomyces species can grow in tissue as small, hard colonies, which are referred to as sulfur granules. Gram stain is incorrect because this test will detect the presence of Gram-positive or Gram-negative organisms. By performing a Gram stain test, the presence of aerobic actinomycetes can be detected by the presence of Gram-positive branching rods. This test will not detect the presence of sulfur granules. Acid-fast stain is incorrect as this test is used to assist in identifying Nocardia species because Nocardia is weakly or partially acid-fast positive. This test does not detect the presence of sulfur granules. Gomori methenamine-Silver (GMS) is incorrect because this test is used to detect aerobic actinomycetes filaments from tissue specimens. It does not detect the presence of sulfur granules.
Which of the following antigens are well developed on fetal cells? A- Lewis B- ABO C- Kell D- I
C- Kell Antigens develop at various rates both in utero and after birth. Kell blood group antigens can be detected on fetal cells at 10 weeks gestation and are well developed at birth. ABO antigens are present on fetal cells but expression is only 25%-50% of that we see on adult RBCs. Lewis antigens and the I antigen are all poorly developed on fetal cells.
Lewis Blood Group System is a human blood group unlike most others. The antigen is produced and secreted by exocrine glands, eventually adsorbing to the surface of red blood cells. Its expression is based on the genetic expression of the Lewis and Secretor genes. Based on the following genotype (Le) (Se), what would you predict the Lewis antigen phenotypic expression to be? A- Le(a- b-) B- Le(a+ b+) C- Le(a- b+) D- Le(a+ b-)
C- Le(a- b+) A person with a functional Lewis gene (Le) and functional Secretor gene (Se) expresses the phenotype Le(a-b+). Phenotype Lewis Genotype Secretor Genotype Le(a+b-) Le sese Le(a-b+) Le Se Le(a-b-) lele sese or Se Essentially, a functional Lewis gene codes for the enzyme fucosyltransferase 3, which adds fucose to an oligosaccharide precursor at the penultimate position. Meanwhile, a functional Secretor gene codes for the enzyme fucosyltransferase 2, which adds fucose to an oligosaccharide precursor at the terminal position. If a person has Le expression but is a nonsecretor (sese), he will express a phenotype of Le(a+b-). If a person has Le expression and is also a secretor (Se), he will express a phenotype of Le(a-b+). If a person does not have Le expression (lele), it does not matter if he is a Secretor (Se) or nonsecretor (sese), he will always express the phenotype Le(a-b-).
Which of the following viruses or diseases is screened for in blood donors only using questions asked during the donor screening and selection process? A- Hepatitis B B-West Nile Virus C- Malaria D-HIV
C- Malaria Currently, there is no FDA-approved test available to screen donors for malarial infections. Donors are screened solely by questioning about travel to or residence in malaria-endemic areas. Blood donors are screened for Hepatitis B and HIV through both questioning and testing. Potential blood donors are asked questions about high-risk behaviors that are linked to hepatitis and/or HIV infection. Enzyme immunosorbent assays, chemiluminescent immunoassays, and NAT are methods used for donor screening for hepatitis and HIV. Blood donors are screened for West Nile Virus using NAT but are not asked any questions related to this virus during the donor selection and screening process.
What is the most common treatment for hemolytic disease of the fetus and newborn (HDFN) due to ABO incompatibility? A- Intravenous immunoglobuli therapy B- Intrauterine tranfusion C- Phototherapy D- Exchange transfusion
C- Phototherapy ABO incompatibility is now the most common cause of HDFN. The type of HDFN is usually mild, and only in extremely rare cases does it cause severe anemia. Most often, the symptoms include hyperbilirubinemia and jaundice (12-48 hours after birth). Phototherapy is the treatment of choice for this increase in bilirubin
MCV is calculated using which of the following parameters? A- Hgb and RBC B- Hct and Hgb C- RBC and Hct D- RBC and MCHC
C- RBC and Hct The correct answer is RBC and Hct. Mean cell volume (MCV) is the average volume/size of RBCs. To calculate the MCV, expressed in femtoliters (fL, or 10-15L), the following formula is used: MCV = Hct (L/L) x 1000 / RBC count (x10^12/L) The mean cell hemoglobin (MCH) is the average weight of hemoglobin in individual RBCs. Hgb and RBC are used in the MCH calculation. The mean cell hemoglobin concentration (MCHC) is the ratio of hemoglobin mass to volume in which it is contained. Hgb and Hct are used in the MCHC calculation. The RBC and MCHC are not used together in the calculation for any of the RBC indices.
What physiological factor causes sedimentation in the Erythrocyte Sedimentation Rate (ESR)? A-Elevated levels of immunoglobulins B- Increased concentrations of fibrinogen C- Rouleaux formation D- Tilted tube, varying from the vertical
C- Rouleaux formation The stacking of the red blood cells, a phenomenon is known as rouleaux formation, is the physiological principle behind ESR methods. The reference range for a male or child is 0-10 mm/hr, while the reference range for a female is 0-20 mm/hr. Increased ESR levels could be an indication of inflammation or infection. Increasing plasma proteins (primarily acute phase proteins such as C-reactive protein) seen in inflammation can contribute to increased stacking of red blood cells causing higher ESR levels.
Which one of the following is a TRUE statement concerning alkaline phosphatase? A- It is optimally active at pH 5 B-It is decreased in bone disorders involving the osteoblasts C-It is increased in obstructive jaundice D- It is increased in myocardial infarctions
C-It is increased in obstructive jaundice The only correct answer is choice 3, as increased levels of alkaline phosphatase are found in patients suffering from obstructive jaundice. This enzyme is optimally active around a pH of 9.0-10.0 and is increased in bone disorders involving osteoblasts such as Paget's disease.
Which of the following major cellular elements does not develop solely in the bone marrow? A- monocyte B- neutrophil C-lymphocyte D- marcophage
C-lymphocyte Bone marrow is the site of myeloid, erythroid, and megakaryocyte as well as early stages of lymphoid cell development. From the major blood cells found in the peripheral blood, the lymphocytes may be produced not only in the bone marrow but also in lymphoid tissues. Bone marrow and thymus are considered primary lymphoid tissues: tissue in which lymphocytes from non-functional precursor cells develop and differentiate into immunocompetent lymphocytes. Spleen and lymph nodes are considered secondary lymphoid tissues in which T and B cells further divide and differentiate into effector and memory cells.
In post-hepatic jaundice, why is urobilinogen decreased? A- Because there is a decrease in bilirubin being metabolized B- Because there is a increase in bilirubin being metabolized C- Because the liver is not conjugating bilirubin D- Because there is a blockage of conjugated bilirubin being excreted from the liver to intestine
D- Because there is a blockage of conjugated bilirubin being excreted from the liver to intestine The correct answer is because there is a blockage of conjugated bilirubin being excreted from the liver to the intestine. By definition, post-hepatic jaundice is blockage or issue with liver excretions into the bile ducts and intestines (hence post: after the liver). Due to the decreased excretion of products from the liver, there will be less conjugated bilirubin being excreted, leading to a decrease in the formation of urobilinogen. Urobilinogen is created from conjugated bilirubin in the intestines from the work of bacteria. If there were an issue with the liver's ability to conjugate or metabolize, we would see hepatic jaundice, not post-hepatic. On the other hand, a decrease or increase in bilirubin metabolism or an increase in hemolysis would be either pre-hepatic or hepatic jaundice.
Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps? A- Extraction, annealing, denaturation B- Denaturation, annealing, extraction C- Denaturation, extension, annealing D- Denaturation, annealing, extension
D- Denaturation, annealing, extension The correct answer is denaturation, annealing, extension. Extraction of the DNA from the clinical sample occurs before the initiation of PCR. Once extracted, the sample is heated to a temperature where the strands of DNA separate (denaturation). Next, the temperature is lowered, and the primers attach (anneal) to their complementary targets. Lastly, the temperature is raised, and new strands of DNA are synthesized (extension), utilizing free nucleotides in the reaction mixture.
What is the mechanism of action for methotrexate? A-Inhibits ribosome function B- Inhibits RNA synthesis C- Inhibits protein synthesis D- Inhibits DNA synthesis
D- Inhibits DNA synthesis Specifically, methotrexate inhibits DNA synthesis in all cells. Neoplastic cells, which have a higher rate of mitosis, absorb more methotrexate than normal cells. This therapy is useful in treating and reducing rapidly dividing cells in diseases such as cancer, lymphomas, and leukemias and may also be used for rheumatoid arthritis.
Analytical sensitivity of a method generally refers to: A-Its ability to measure only what is being assayed. B- Its ability to measure high concentrations of analytes C- It not being affected by interfering substances. D- Its ability to measure low concentrations of analytes
D- Its ability to measure low concentrations of analytes The sensitivity of a test refers to its ability to measure low concentrations of analytes. A numerical value can be calculated for a test's sensitivity that represents the probability of it returning a "true" value for samples (i.e., patients) from the population of interest (i.e., samples from patients who do in fact have the disease in question). Sensitivity is the number of true positive results (TP) divided by the sum of true positive and false negative (FN) results, i.e., sensitivity = TP/(TP + FN).
Lewis Blood Group System is a human blood group unlike most others. The antigen is produced and secreted by exocrine glands, eventually adsorbing to the surface of red blood cells. Its expression is based on the genetic expression of the Lewis and Secretor genes. Based on the following genotype (Le) (sese), what would you predict the Lewis antigen phenotypic expression to be? A- Le(a- b-) B- Le(a+ b+) C- Le(a- b+) D- Le(a+ b-)
D- Le(a+ b-) The correct answer is: Le(a+ b-) A person with a functional Lewis gene (Le) and nonfunctional Secretor gene (sese) expresses the phenotype Le(a+b-) A person who is Le(a- b-) lacks the Le gene regardless of secretor status. The Le (a+ b+) phenotype is very rare except among Asians and would require the individual to have a secretor (Se) gene. The Le (a- b+) phenotype would require the individual to have a secretor (Se) gene. Phenotype Lewis Genotype Secretor Genotype Le(a+b-) Le sese Le(a-b+) Le Se Le(a-b-) lele sese or Se
Patterns of hydrolysis of tyrosine, xanthine, and casein are characteristics helpful in making species identifications within which genera? A- Actinomyces B- Mycobacterium C- Corynebacterium D- Nocardia
D- Nocardia The correct answer is Nocardia. The selective ability to hydrolyze tyrosine, xanthine and casein are characteristics helpful in the species identification of the aerobic actinomycetes, including Nocardia species. These tests have not been used in the identification of any of the other genera of bacteria listed in this question, even though they do have other characteristics in common with Nocardia species.
The prozone effect can be described by all of the following EXCEPT: A- Results in a false negative reaction B- The result of antibody excess C- Dilution of antibody can help prevent its occurrence D- Results in a false positive reaction
D- Results in a false positive reaction Prozone is the result of antibody excess--where the concentration of antibody exceeds the concentration of antigen; it appears as a false negative, which can become positive as the patient's serum is diluted. It does not yeild a false positive reaction.
HLA antibodies are responsible for which of the following transfusion reactions? A- Allergic Transfusion Rxn B- Transfusion associted sepsis C- Trasfusion associated circulatory overload D- Tansfusion related acute lung injusry (TRALI)
D- Tansfusion related acute lung injusry (TRALI) Antibodies to human leukocyte antigens (HLA) are responsible for transfusion-related acute lung injury (TRALI). The pathogenesis of this transfusion reaction is not fully understood, but there are two accepted mechanisms. The first involves antibodies to human leukocyte antigens or human neutrophil antigens transfused into a recipient. The antibodies bind and activate the recipient's leukocytes. The second mechanism involves a patient undergoing some event that primes their leukocytes. This includes a disease state, infection, or trauma). The patient is then transfused with a product that contains cytokines or anti-leukocyte antibodies, which then activate the already primed leukocytes. Both mechanisms cause leukocytes (especially neutrophils) to aggregate in the lungs. As a result, there is damage to the endothelium, which leads to an increase in pulmonary capillary permeability and noncardiogenic pulmonary edema. Allergic reactions are due to a recipient having an antibody (usually IgE) to a protein in the donor's plasma. They can also be caused by donor antibodies to a protein present in the recipient's plasma. Transfusion-associated sepsis is caused by bacterial contamination of a transfused product. Transfusion-associated circulatory overload is caused by the inability of a patient's circulatory system to handle the additional workload from the transfused product. It occurs when the volume or rate of transfusion is too high.
