Medical Laboratory Technologist Prometric exam questions

The Medical Laboratory Technologist exam in every GCC country

From each regulator's own exam pages; anything a regulator does not publish says so. Assessment mode also depends on your licence title, so confirm your route on your eligibility notice.

12 worked Medical Laboratory Technologist practice questions

Original exam-style questions from the bank, spread across the blueprint domains. They are not real or recalled exam questions. Try each one, then open the answer for the rationale and reference. None of them appear in the free mock exam, so reading them will not spoil it.

1. Question 1 · General Laboratory, Quality Management & Safety

   A healthcare worker with a documented adequate anti-HBs antibody response (a known responder) sustains a needlestick from a hepatitis B surface antigen-positive source. What is the recommended post-exposure management for hepatitis B?

   1. AAdminister hepatitis B immune globulin (HBIG) plus a full new vaccine series
   2. BRestart the vaccine series only, without HBIG
   3. CAdminister two doses of HBIG one month apart
   4. DNo hepatitis B treatment is needed because the worker is an immune responder
   Show answer and explanation

   Correct answer: D. No hepatitis B treatment is needed because the worker is an immune responder

   A vaccinated worker with a documented adequate anti-HBs level (>=10 mIU/mL, a known responder) is considered protected and needs no HBIG or additional vaccine after HBsAg-positive exposure. HBIG and/or vaccination are reserved for non-responders, incompletely vaccinated, or those with unknown antibody status.

   Reference: CDC Updated PHS Guidelines for Management of Occupational Exposures to HBV, HCV, and HIV (2013); MMWR

2. Question 2 · Hematology

   In differentiating acute monocytic leukemia from acute myeloblastic leukemia, a pair of esterase stains is often used. Which cytochemical pattern best supports a monocytic lineage?

   1. APositive specific (chloroacetate) esterase and negative nonspecific esterase
   2. BPositive nonspecific (alpha-naphthyl butyrate) esterase that is inhibited by sodium fluoride
   3. CPositive periodic acid-Schiff (PAS) in a coarse block pattern
   4. DPositive Prussian blue staining of the cytoplasm
   Show answer and explanation

   Correct answer: B. Positive nonspecific (alpha-naphthyl butyrate) esterase that is inhibited by sodium fluoride

   Monocytes and their precursors show strong nonspecific esterase activity (alpha-naphthyl butyrate or acetate) that is characteristically inhibited by sodium fluoride, distinguishing them from granulocytes. Specific chloroacetate esterase marks the granulocytic (myeloblastic) series instead. Coarse block PAS positivity suggests lymphoblasts, and Prussian blue detects iron (siderotic granules/ring sideroblasts), not monocytic differentiation.

   Reference: Rodak's Hematology: Clinical Principles and Applications, 6th ed. (Elsevier, 2020), cytochemistry chapter

3. Question 3 · Immunohematology (Blood Group Serology)

   When grading tube agglutination, hemolysis in the presence of complement-binding antibodies should be interpreted as which of the following?

   1. AA positive reaction equivalent in significance to agglutination
   2. BA negative reaction because no clumps are seen
   3. CAn invalid result requiring repeat with fresh cells only
   4. DRouleaux formation
   Show answer and explanation

   Correct answer: A. A positive reaction equivalent in significance to agglutination

   Hemolysis produced by a complement-activating antibody (for example anti-A, anti-B, or some anti-Jka/Jkb) indicates an antigen-antibody reaction and is recorded as a positive result, often as strong as or stronger than visible agglutination. Interpreting it as negative would miss clinically significant antibodies. It is a genuine reaction, not an invalid one, and it is unrelated to rouleaux, which is a pseudoagglutination that disperses with saline replacement.

   Reference: AABB Technical Manual, 20th edition, 2020

4. Question 4 · Urinalysis & Body Fluids

   A post-vasectomy patient submits a semen sample to confirm sterility. Which examination finding is required before the specimen can be reported as consistent with a successful vasectomy?

   1. AAbsence of spermatozoa confirmed on examination of a centrifuged specimen
   2. BPresence of fructose in the seminal plasma
   3. CNormal semen volume greater than 1.5 mL
   4. DPresence of at least 15 million sperm/mL
   Show answer and explanation

   Correct answer: A. Absence of spermatozoa confirmed on examination of a centrifuged specimen

   Post-vasectomy semen analysis aims to confirm azoospermia; because sperm may be sparse, the specimen (or its pellet after centrifugation) must be examined and reported as showing no spermatozoa. A sperm concentration of 15 million/mL is a fertility reference value, not a sterility criterion, and volume or fructose (which reflects seminal vesicle function) do not confirm vasectomy success.

   Reference: WHO Laboratory Manual for the Examination and Processing of Human Semen, 6th ed. (2021)

5. Question 5 · Immunology & Serology

   A patient with suspected connective tissue disease has an ANA showing a homogeneous (diffuse) staining pattern by indirect immunofluorescence. This pattern is classically associated with antibodies against:

   1. ANucleolar RNA
   2. BCytoplasmic Jo-1 antigen
   3. CCentromere proteins
   4. DdsDNA and histones (deoxyribonucleoprotein)
   Show answer and explanation

   Correct answer: D. dsDNA and histones (deoxyribonucleoprotein)

   The homogeneous ANA pattern reflects antibodies to dsDNA and histones (nucleoprotein) and is seen in SLE and drug-induced lupus. A nucleolar pattern suggests scleroderma, a discrete speckled/centromere pattern suggests limited scleroderma (CREST), and anti-Jo-1 is a cytoplasmic antibody linked to polymyositis.

   Reference: Turgeon, Immunology & Serology in Laboratory Medicine, 7th ed., 2022

6. Question 6 · Clinical Chemistry

   Therapeutic drug monitoring is most clinically valuable for drugs that have which characteristic?

   1. AA wide therapeutic index and predictable dose-response
   2. BA narrow therapeutic index where toxic and effective concentrations are close together
   3. CNo relationship between serum concentration and effect
   4. DRapid complete metabolism to inactive products within minutes
   Show answer and explanation

   Correct answer: B. A narrow therapeutic index where toxic and effective concentrations are close together

   TDM is most useful for drugs with a narrow therapeutic index (e.g., digoxin, phenytoin, aminoglycosides, lithium, theophylline), where the effective and toxic concentrations are close and small dosing changes can cause toxicity or treatment failure. Drugs with a wide margin or no concentration-effect relationship gain little from monitoring.

   Reference: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 6th ed., 2018

7. Question 7 · Microbiology

   As part of media quality control, a technologist inoculates a new lot of MacConkey agar with a stock strain to confirm the inhibition of Gram-positive growth. Which organism is the most appropriate QC strain for this specific purpose?

   1. AEscherichia coli ATCC 25922 (expected growth, pink)
   2. BEnterococcus faecalis ATCC 29212 (expected partial to no growth)
   3. CPseudomonas aeruginosa ATCC 27853 (expected colorless growth)
   4. DProteus mirabilis (expected swarming)
   Show answer and explanation

   Correct answer: B. Enterococcus faecalis ATCC 29212 (expected partial to no growth)

   To verify the selective (inhibitory) property of MacConkey agar, a Gram-positive control such as Enterococcus/Staphylococcus is used to confirm partial or complete inhibition. E. coli and P. aeruginosa are Gram-negative growth controls that confirm the medium supports growth and differentiates fermenters, not the inhibitory property. Proteus swarming is not the intended QC endpoint for selectivity.

   Reference: CLSI M22, Quality Control for Commercially Prepared Microbiological Culture Media (2018)

8. Question 8 · Blood Banking & Transfusion Services

   A patient with recurrent severe allergic/anaphylactic reactions to plasma proteins and documented IgA deficiency requires red cells. Which product modification is most appropriate?

   1. AIrradiated red cells
   2. BWashed red cells
   3. CCMV-negative red cells
   4. DFrozen-thawed red cells only for storage
   Show answer and explanation

   Correct answer: B. Washed red cells

   Washed red cells have the residual plasma proteins (including IgA) removed, making them the product of choice for patients with severe allergic/anaphylactic reactions or IgA deficiency with anti-IgA. Irradiation prevents TA-GVHD, CMV-negative units reduce CMV risk, and freezing/deglycerolizing is primarily for rare-unit storage though it also washes plasma.

   Reference: AABB Technical Manual, 20th ed.; Circular of Information (2021)

9. Question 9 · Coagulation & Hemostasis

   Platelet aggregation studies show an absent primary and secondary wave with ADP, collagen, and epinephrine, but a normal response to ristocetin. This pattern is most consistent with which disorder?

   1. ABernard-Soulier syndrome
   2. BGlanzmann thrombasthenia
   3. CVon Willebrand disease
   4. DStorage pool disease
   Show answer and explanation

   Correct answer: B. Glanzmann thrombasthenia

   Glanzmann thrombasthenia is a defect of platelet glycoprotein IIb/IIIa, which mediates fibrinogen-dependent aggregation; therefore aggregation to ADP, collagen, and epinephrine is absent while ristocetin agglutination (GPIb/vWF dependent) is preserved. Bernard-Soulier and vWD show the opposite pattern (absent ristocetin response), and storage pool disease typically shows a blunted second wave.

   Reference: Rodak's Hematology, 6th ed., 2020; platelet function testing guidelines

10. Question 10 · General Laboratory, Quality Management & Safety

    A gray-top tube containing sodium fluoride and potassium oxalate is used primarily to preserve which analyte, and by what mechanism does the fluoride act?

    1. AGlucose; fluoride inhibits glycolytic enzymes such as enolase
    2. BCalcium; fluoride chelates calcium ions
    3. CPotassium; fluoride prevents cellular potassium leakage
    4. DLactate; fluoride activates lactate dehydrogenase
    Show answer and explanation

    Correct answer: A. Glucose; fluoride inhibits glycolytic enzymes such as enolase

    Sodium fluoride is an antiglycolytic agent that inhibits enolase in the glycolytic pathway, preserving glucose in the specimen; potassium oxalate acts as the anticoagulant by binding calcium. Fluoride does not chelate calcium (oxalate does that), does not prevent potassium leakage, and inhibits rather than activates glycolytic enzymes.

    Reference: Burtis & Bruns, Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics, 8th ed. (2019)

11. Question 11 · Hematology

    Which feature most reliably favors a reactive/benign leukocytosis over an acute leukemia on a peripheral smear?

    1. AUniform population of cells with fine chromatin and prominent nucleoli
    2. BAuer rods within immature cells
    3. CPresence of a spectrum of maturing granulocytic forms without a blast excess
    4. DMarked thrombocytopenia with circulating blasts
    Show answer and explanation

    Correct answer: C. Presence of a spectrum of maturing granulocytic forms without a blast excess

    A reactive (leukemoid) response typically shows a complete spectrum of maturing granulocytes (myelocytes, metamyelocytes, bands, segmented) with few or no blasts and often toxic changes. A monomorphic immature population with open chromatin and nucleoli, Auer rods, or blasts with thrombocytopenia point instead to acute leukemia.

    Reference: Rodak's Hematology: Clinical Principles and Applications, 6th ed. (2020)

12. Question 12 · Microbiology

    An enzyme-linked immunosorbent assay (ELISA) detecting IgM antibody to a virus is positive in a patient with an acute febrile illness. What does the presence of specific IgM most strongly indicate?

    1. ALong-standing immunity from remote past infection
    2. BRecent or acute/current infection
    3. CSuccessful vaccination years earlier
    4. DAbsence of any infection
    Show answer and explanation

    Correct answer: B. Recent or acute/current infection

    Virus-specific IgM antibodies appear early and are the first immunoglobulin produced in a primary immune response, so a positive IgM indicates recent or acute infection. IgG, not IgM, reflects past infection or vaccine-induced long-term immunity. A positive IgM does not indicate absence of infection. Detecting IgM is used to identify current/recent viral infection.

    Reference: Murray et al., Medical Microbiology, 9th ed. (Elsevier, 2021)

Medical Laboratory Technologist reference books and guidelines

Every question in this bank names the textbook or guideline its answer rests on. These are the sources our Medical Laboratory Technologist questions cite most often - the reading list to revise from alongside the bank.

Where your regulator publishes a reading list, use the editions it names. Exam questions are not taken from any one book.