تقنية مختبرات (3) | أسئلة الهيئة السعودية للتخصصات الصحية

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تقنية مختبرات (3) مع (Answer key with explanations)

General Lab.

Choose the most appropriate single answer.

1. The primary mechanism responsible for glomerular filtration is:

a.      Osmotic gradient

b.      Concentration of blood components

c.      Rate of blood flow through the kidneys

d.      Hydrostatic differential in glomerular tufts 

d 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 15,000 are not filtered.

2. Which of the following best describes a minor crossmatch:

a.      Reaction of donor cells with recipient serum

b.      Reaction of donor cells with AHG

c.      Reaction of recipient cells with AHG

d.      Reaction of donor serum with recipient cells

d

3. Fire requires what three elements?

a.      heat, fuel, oxygen

b.      paper, match, gasoline

c.      heat, fuel, nitrogen

d.      lighter fluid, charcoal, grill

a

4. A 20 year-old female was admitted into the hospital complaining of 10 to 15 bloody mucous stools per day, fever, gastrointestinal disturbances, abdominal pain, and nausea. The preliminary O & P report went out as "Probable Entamoeba histolytica trophozoites and cysts, confirmation pending." This patient is most likely suffering from:

a.      Traveler's diarrhea

b.      Extraintestinal amebiasis

c.      Intestinal amebiasis

d.      Giardiasis

c

5. Which of the following Rh antigens is found the highest frequency in the Caucasian population:

a.      C

b.      E

c.      c

d.      e

d The e antigen is present in 98% of the Caucasian population.

6. What is another name used to designate a fully committed B-lymphocyte:

a.      T-lymphocyte

b.      Reactive lymphocyte

c.      Large lymphocyte

d.      Plasma cell

d Plasma cells are the end stage of B lymphocyte maturation; they are not normally seen in peripheral blood.

7. Serum calcitonin is typically elevated in which of the following conditions:

a.      Medullary carcinoma of the thyroid

b.      Hyperthyroidism

c.      Glioblastoma

d.      Adrenal adenoma

a Serum calcitonin is normally produced by the C cells of the thyroid. It functions to reduce serum calcium by inhibiting release of calcium from bone. It is a peptide with a molecular weight of 3400, and has a half life of approximately 12 minutes. It is characteristically elevated in medullary carcinoma of the thyroid. Since medullary carcinoma often occurs as an autosomal disorder, family members of patients with this condition should be screened for serum calcitonin.

8. Warfarin inhibits all the following coagulation Factors except:

a.      Factor II

b.      Factor IX

c.      Factor VII

d.      Factor XI

d Warfarin only inhibits vitamin K dependent factors; Factor XI is not vitamin K dependent.

9. Serum proteins can be separated by cellulose acetate electrophoresis into how many basic fractions:

a.      4 fractions

b.      5 fractions

c.      6 fractions

d.      7 fractions

b The five basic fractions are albumin, alpha-1, alpha-2, beta, and gamma globulins.

10. Which of the following specimens would not be considered suitable for anaerobic culture:

a.      Drainage from a puncture wound

b.      Throat swab

c.      Drainage from abdomen

d.      Blood culture

b Anaerobes are predominant in the colon. Anaerobic habitats have reduced oxygen tension usually resulting from the metabolic activity of aerobic organisms. Thus, anaerobic infections are usually polymicrobial, with aerobes, facultative anaerobes, and obligate anaerobes all contributing to the infection.

11. following is not necessary for bacteria to grow successfully on artificial media:

a.      Pure isolate

b.      Proper temperature

c.      Proper Ph

d.      Proper moisture

a A mixture of bacteria can easily grow together on media as long as the other factors are all maintained correctly.

12. Why would a unit of group O blood never be administered to a Bombay patient:

a.      Anti-A in donor

b.      Anti-B in donor

c.      Anti-H in donor

d.      Anti-H in recipient

d The classic Bombay phenotype (Oh) is characterized by the absence of A, B and H antigens, and the presence of anti-H, which will react from 4o to 37o C. Bombay patients must therefore be transfused only with blood from donors of the Bombay phenotype.

13. Total magnification of a microscope can be determined by:

a.      Multiplying power of objective times the power of the ocular

b.      Dividing the power of objective by the power of the ocular

c.      Dividing the power of the ocular by the power of the objective

d.      Adding the power of the ocular and objective together X 10

a

14. IgM antibodies directed against red cells generally:

a.      React best at 37 degrees Celsius

b.      Cause severe hemolytic reactions

c.      Are identified using the AHG test

d.      React best at room temperature

d

15. Which of the following organisms is not an aerobic organism:

a.      Francisella

b.      Bacteroides

c.      Pseudomonas

d.      Neisseria

b Francisella tularensis is an aerobic gram-negative coccobaccillary organism requiring cystine or cysteine to grow. It causes tuleremia, which can manifest as cutaneous papules and ulcers, conjunctivitis, fever, myalgias, and lymphadenopathy. It can be diagnosed by culture on appropriate media, or serology. Bacteroides fragilis is an anaerobic gram-negative rod which is resistant to most penicillins. It can cause a variety of life threatening infections. Pseudomonas aeruginosa is a stictly aerobic gram-negative motile bacillus; it causes a variety of infections especially among patients who are immunocompromised for a variety of reasons, and it causes wound infections in moist air.

16. Which of the following statements about Rickettsia is false:

a.      They are obligate intracellular parasites

b.      They are gram negative bacilli

c.      Associated diseases are usually diagnosed by serology

d.      They are cultured in many hospital laboratories

d Various Rickettsial species cause typhus, Rocky Mountain spotted fever, Rickettsialpox, and Q fever. Rickettsial organisms are cultured only by research and reference laboratories, and the diagnosis is usually achieved by a combination of clinical findings, and acute and convalescent serology. Early diagnosis of Rocky Mountain spotted fever can also be made by immunoflourescence testing of a skin biopsy, where Rickettsia can often be found within endothelial cells of capillary vessels.

17. Coarse basophilic stippling in all of the following EXCEPT:

a.      Megaloblastic anemias

b.      Thalassemias

c.      Lead poisoning

d.      Hemolytic anemia

d Hemolytic anemia may be associated with fine basophilic stippling due to precipitated RNA in polychromatophilic erythrocytes. It is not usually associated with coarse stippling. The other conditions above have coarse stippling in the setting of abnormal hemoglobin synthesis.

18. Human chorionic gonadatropin (hCG) is used in the determination of:

a.      Liver function

b.      Fetal maturity

c.      Pregnancy

d.      Steroid levels

c

19. Estrogen and progesterone markers are most commonly used to provide prognostic information about:

a.      Breast cancer

b.      Uterine cancer

c.      Menopause

d.      Cervical cancer

a Patients with tumors positive for both estrogen and progesterone receptors tend to respond favorably to hormonal therapy, whereas those without generally do not. Patients with positive estrogen and progesterone receptors also have a somewhat better prognosis.

20. Materials such as strong acids and bases are classified as:

a.      Corrosives

b.      Chemical irritants

c.      Flammable liquids

d.      Carcinogens

a

21. Elevation in conjugated bilirubin is most likely to be found in which of the following conditions:

a.      Transfusion reactions

b.      Erythroblastosis fetalis

c.      Cirrhosis of the liver

d.      Biliary obstruction

d Posthepatic jaundice is the result of bile duct obstruction, not impaired hepatic function. It will result in elevation of direct (conjugated) bilirubin.

22. Pluripotential stem cells are capable of producing which of the following:

a.      Only T-lymphocyte and B-lymphocyte subsets

b.      Erythropoietin, thrombopoietin and leukopoietin

c.      Lymphoid and myeloid stem cells

d.      Daughter cells from only a single cell line

d Pluripotential stem cells are ultimately capable of differentiating into all types of leukocytes.

23. What is the largest constituent of plasma nonprotein nitrogen:

a.      Ammonia

b.      Creatinine

c.      Ketones

d.      Urea

d

24. What principle(s) of flow cytometry are employed when performing immunophenotyping:

a.      Defraction gradients Impedance

b.      Defraction gradients and impedance

c.      Flourescent antibody tagging and light scatter

c Flow cytometry employs a combination of fluorescent antibody tagging of cells and analysis with laser light scatter.

25. Which is arranged from least mature to most mature:

a.       Stem Cell, Rubriblast, Prorubricyte, Rubricyte, Metarubricyte, Reticulocyte, Erythrocyte

b.      Stem Cell, Prorubricyte, Metarubricyte, Erythrocyte, Rubriblast, Rubricyte, Reticulocyte

c.       Erythrocyte, Reticulocyte, Metarubricyte, Rubricyte, Prorubricyte, Rubriblast, Stem Cell

d.      Rubricyte, Rubriblast, Stem Cell, Prorubricyte, Erythrocyte, Reticulocyte, Metarubrictye

a

26. The term used to describe patients with absence of Rh antigens is:

a.      Rhd

b.      Rhnull

c.      Rhmod

d.      Rho

b Rhnull individuals have no Rh antigens. Rhmod individuals show reduced and varied reactivity with Rh antigens.

27. Which is the best method for examination of synovial crystals:

a.      Phase contrast

b.      Darkfield microscopy

c.      Brightfield microscopy

d.      Polarized light

d A polarizing microscope with a first order red compensator is used to identify identify crystals in synovial fluid: Needle shaped monosodium urate crystals are strongly negatively birefringent, while rhomboid calcium pyrophosphate crystals are weakly positively birefringent.

28. Which of the following antibodies is the most common cause of hemolytic disease of the newborn:

a.      Anti-A

b.      Anti-B

c.      Anti-E

d.      Anti-D

d

29.  Which of the following is not true about members of the Enterobacteriaceae:

a.      Gram-negative

b.      Oxidase positive

c.      Reduce nitrate to nitrite

d.      Ferment glucose

b Any oxidase-positive organism can be excluded from the Enterobacteriaceae. The other characteristics are as a rule present in these organisms.

30. Which one of the following is not a benefit of using packed RBCs:

a.      Decreasing the load of potential donor antibodies

b.      Decreasing the risk of transfusion associated infection

c.      Decreasing plasma volume

d.      More efficient use of the whole blood unit

b

31. The adult worms of which of the following reside in the intestine or its blood vessels:

a.      Heterophyes heterophyes

b.      Schistosoma mansoni

c.      Clonorchis sinensis

d.      Schistosoma haematobium

e.      Both a & b

e

32. If a test is said to have a sensitivity of 95%, it will :

a.      Miss 5 out of 100 negatives

b.      Miss 5 out of 100 positives

c.      Detect 5 out of 100 positives

d.      Detect 5 out of 100 negatives

c A sensitivity of 95% means that 5 results out of a possible 100 that should have been detected as positive by a method will have been reported as negative. These results are termed false negatives.

33. Which one of the following are not associated with a polyclonal (broadbased) increase in gamma globulins?

a.      Liver disease

b.      Chronic inflammation

c.      Immune reaction

d.      Immunodeficiency

d Immunodeficiency would, of course, generally be associated with a decrease in serum immunoglobulin levels, and an associated decreased gamma band.

34. Which of the following tests would be used to directly document the presence of a specific organism in a clinical specimen:

a.      ELISA test

b.      Hemagglutination test

c.      Hemagglutination inhibition test

d.      Direct fluorescent antibody test

d A direct fluorescent antibody test (DFA) can be used, for example, to detect antigens of Legionella, Bordetella, Neisseria, and Treponema in appropriate clinical specimens. However DFA can detect only antigens, not antibodies.

35. That portion of an enzyme which is separated from its cofactor is called a(n):

a.      Partial enzyme

b.      Isoenzyme

c.      Coenzyme

d.      Apoenzyme

d A partial enzyme is not an actual term used in the laboratory. An isoenzyme is a related enzyme with a different chemical structure. Finally, a coenzyme is a non-protein molecule (often a vitamin) that helps an enzyme become active.

36. Increases in the MB fraction of CK is associated with:

a.      Liver disease

b.      Bone disease

c.      Muscle trauma

d.      Mycardial infarction

d The isoenzyme CK-MB is fairly cardiac specific. It is elevated within 6 to 8 hours of a myocardial infarction, and remains elevated for about 2 to 3 days post infarction.

37. A normal hemoglobin molecule is comprised of the following:

a.      Ferrous iron and four globin chains

b.      Four heme and four globin chains

c.      Four heme and one globin chains

d.      One heme and four globin chains.

b A normal hemoglobin molecule consists of a tetramer with a molecular weight of 64,500 daltons. The constituent monomers are each composed of one heme molecule, and one polypeptide globin chain.

38. Increased excretion of creatinine would be expected in which of the following groups:

a.      Elderly males/females

b.      Adult males

c.      Adult females

d.      Children/infants

b Diets high in meats, and extreme exercise will cause a significant increase in creatinine excretion.

39. Pheochromocytoma is a tumor of the adrenal medulla that results in elevated urinary levels of all but which of the following:

a.      Cortisol

b.      Free catecholamines

c.      Metanephrines

d.      Vanillylmandelic acid

a Pheochromocytoma is an adrenal or extra adrenal neoplasm that secretes catecholamines. Patients with pheochromocytoma often exhibit persistent and paroxysmal hypertension. The single best screening test is urinary metanephrines. Urinary free catecholamines, and vanillylmandelic acid are also elevated.

40. Match the clotting factor with its commonly associated name:

a.      Factor II                1.    Fibrinogen

b.      Factor I                 2.    Prothrombin 

c.      Factor V                3.    Proaccelerin

a-2, b-1, c-3

41. Match the type of hepatitis with its route of transmission

a.      Fecal and Oral       1.  Hepatitis C

b.      Parenteral              2.   Hepatitis A

c.      Parenteral              3.   Hepatitis B

a-2, b-3, c-1 Hepatitis A is spread through the fecal-oral route. Hepatitis B is most commonly spread through parenteral means, but nonparenteral routes such as transmission through pregnancy, sexual contact, and exposure to infected body fluids are also important. Hepatitis C is spread through parenteral routes; pregnancy, sexual contact, and in households is possible, but much less likely than with hepatitis B.

يُتبع  Continued