Clinical Pathology Prometric exam questions with answers

1. Question 1Clinical Chemistrymedium

   A patient with acute pancreatitis has a grossly lipemic sample. Sodium by indirect ion-selective electrode is 124 mmol/L, measured serum osmolality is 290 mmol/kg and glucose is normal. What best explains the low sodium?

   1. AInappropriate antidiuretic hormone secretion
   2. BOsmotic water shift caused by severe hyperglycemia
   3. CIn vitro hemolysis of the specimen
   4. DElectrolyte exclusion effect of an indirect method
   Show answer and explanation▾

   Answer: D. Electrolyte exclusion effect of an indirect method

   Indirect ISE methods dilute the sample and assume a normal water fraction, so excess lipid lowers the reported sodium while osmolality stays normal. SIADH would produce true hypo-osmolality, which is absent here; a direct ISE (blood gas analyzer) gives the true value.

2. Question 2Clinical Chemistryhard

   A well patient has persistently raised serum amylase for 6 months, normal lipase, normal pancreatic imaging and a low amylase-to-creatinine clearance ratio. What is the most likely diagnosis?

   1. AChronic pancreatitis
   2. BMacroamylasemia
   3. CSalivary gland inflammation
   4. DRenal impairment
   Show answer and explanation▾

   Answer: B. Macroamylasemia

   Macroamylase is amylase bound to immunoglobulin, too large for glomerular filtration, so serum amylase rises while urinary clearance falls and lipase stays normal. Salivary disease raises amylase but the clearance ratio is not low.

3. Question 3Clinical Microbiologymedium

   A well outpatient has one of two blood culture sets positive for coagulase-negative staphylococci after 3 days; there is no prosthetic material or line. How is this best interpreted?

   1. ATrue bacteremia needing vancomycin
   2. BProbable skin contaminant; correlate clinically
   3. CInfective endocarditis until proven otherwise
   4. DLaboratory error requiring a new sample only
   Show answer and explanation▾

   Answer: B. Probable skin contaminant; correlate clinically

   A single positive set of a common skin commensal, with late growth and no risk factors, most likely represents contamination. Treating as true bacteremia exposes the patient to unnecessary vancomycin.

4. Question 4Hematology and Hematopathologymedium

   A 25-year-old has hemoglobin 112 g/L, MCV 62 fL, red cell count 6.1 x 10^12/L, normal ferritin and HbA2 5.4% on HPLC. What is the most likely diagnosis?

   1. AIron deficiency anemia
   2. BBeta thalassemia trait
   3. CAlpha thalassemia silent carrier
   4. DHemoglobin E trait
   Show answer and explanation▾

   Answer: B. Beta thalassemia trait

   Marked microcytosis with a high red cell count, normal iron stores and HbA2 above 3.5% is characteristic of beta thalassemia trait. Iron deficiency is excluded by the normal ferritin and tends to lower, not raise, HbA2.

5. Question 5Laboratory Management, Quality and Safetyeasy

   One level of internal quality control exceeds the mean plus 3 SD for a sodium run. What is the correct action?

   1. AAccept the run and note it as a warning
   2. BRepeat only the control and report patients
   3. CReject the run and investigate before reporting
   4. DRecalibrate after reporting the patient results
   Show answer and explanation▾

   Answer: C. Reject the run and investigate before reporting

   The 1-3s rule detects random error or large systematic error and is a rejection rule. Treating it as a warning (the role of the 1-2s rule) risks releasing erroneous patient results.

6. Question 6Hematology and Hematopathologymedium

   A man with splenomegaly and pancytopenia has B cells positive for CD11c, CD25, CD103 and annexin A1. Which mutation is expected in nearly all such cases?

   1. AJAK2 V617F
   2. BMYD88 L265P
   3. CBRAF V600E
   4. DNOTCH1 PEST domain
   Show answer and explanation▾

   Answer: C. BRAF V600E

   Classic hairy cell leukemia carries BRAF V600E in almost all cases, which also supports targeted therapy. MYD88 L265P is characteristic of lymphoplasmacytic lymphoma, not classic hairy cell leukemia.

7. Question 7Transfusion Medicinehard

   Eight days after transfusion a patient has falling hemoglobin, jaundice and a newly positive DAT; the pre-transfusion antibody screen was negative. Which antibody is classically responsible because its titre falls below detection?

   1. AAnti-Lea
   2. BAnti-M
   3. CAnti-P1
   4. DAnti-Jka
   Show answer and explanation▾

   Answer: D. Anti-Jka

   Kidd antibodies are notorious for evanescence and for anamnestic responses that cause delayed hemolytic reactions. Anti-Lea, anti-M and anti-P1 are usually IgM, cold-reactive and rarely clinically significant.

8. Question 8Transfusion Medicineeasy

   Which ABO group of fresh frozen plasma can be given to a patient of any ABO group?

   1. AGroup AB
   2. BGroup O
   3. CGroup A
   4. DGroup B
   Show answer and explanation▾

   Answer: A. Group AB

   Group AB plasma contains neither anti-A nor anti-B, so it is compatible with all recipients. Group O is the universal red cell group but its plasma contains anti-A and anti-B.

9. Question 9Hematology and Hematopathologymedium

   An automated CBC shows hemoglobin 110 g/L, red cell count 1.8 x 10^12/L, MCV 125 fL and MCHC 420 g/L. The smear shows red cell clumping. What is the best next step?

   1. ARequest vitamin B12 and folate levels
   2. BReport the indices as measured
   3. CRecollect the sample in a citrate tube
   4. DWarm the sample to 37 °C and rerun
   Show answer and explanation▾

   Answer: D. Warm the sample to 37 °C and rerun

   Cold agglutinins cause red cell doublets counted as single large cells, giving falsely low RBC count, high MCV and an impossible MCHC; warming disperses the agglutinates. Investigating B12 deficiency would chase an artifactual macrocytosis.

10. Question 10Hemostasis and Thrombosismedium

    A patient on unfractionated heparin has a 60% platelet fall on day 7 and an intermediate 4Ts score. The PF4-heparin ELISA is weakly positive. Which test best confirms HIT?

    1. ARepeat platelet count in 24 hours
    2. BPeripheral smear for clumping
    3. CSerotonin release assay
    4. DAnti-Xa heparin level
    Show answer and explanation▾

    Answer: C. Serotonin release assay

    Functional assays such as the serotonin release assay detect platelet-activating antibodies and are more specific than immunoassays. A heparin level does not indicate the presence of pathogenic antibodies.

11. Question 11Laboratory Management, Quality and Safetymedium

    An assay has total allowable error 10%, bias 2% and CV 2%. What is its sigma metric?

    1. A4.0
    2. B5.0
    3. C6.0
    4. D3.0
    Show answer and explanation▾

    Answer: A. 4.0

    Sigma = (TEa - bias)/CV = (10 - 2)/2 = 4.0. Calculating 10/2 = 5.0 ignores bias, which overestimates method performance.

12. Question 12Molecular Diagnostics and Cytogeneticsmedium

    A patient with CML on a tyrosine kinase inhibitor has BCR::ABL1 of 0.08% on the International Scale at 12 months. How is this response classified?

    1. AComplete cytogenetic response only
    2. BTreatment failure
    3. CDeep molecular response MR4.5
    4. DMajor molecular response
    Show answer and explanation▾

    Answer: D. Major molecular response

    Major molecular response is BCR::ABL1 of 0.1% IS or less, which is the 12-month target. MR4.5 requires 0.0032% IS or less, a much deeper level than this result.

13. Question 13Transfusion Medicinemedium

    Ten minutes into a red cell transfusion, a patient develops fever, rigors, back pain, hypotension and dark urine. What is the first action?

    1. ASlow the infusion rate and give intravenous paracetamol
    2. BStop the transfusion and keep IV access with saline
    3. CGive an antihistamine and continue the unit
    4. DComplete the unit, then send blood samples
    Show answer and explanation▾

    Answer: B. Stop the transfusion and keep IV access with saline

    Suspected acute hemolysis requires immediate cessation, IV access with saline, a bedside identity check and return of the unit with samples. Slowing the rate continues exposure to incompatible cells and can worsen DIC and renal failure.

14. Question 14Transfusion Medicinemedium

    Two hours after plasma transfusion, a patient develops hypoxemia, bilateral pulmonary infiltrates, fever and hypotension. BNP is normal and there is no fluid overload. What is the most likely diagnosis?

    1. ATransfusion-associated circulatory overload
    2. BAnaphylactic transfusion reaction
    3. CTransfusion-related acute lung injury
    4. DBacterial contamination of the unit
    Show answer and explanation▾

    Answer: C. Transfusion-related acute lung injury

    Acute lung injury within 6 hours with hypotension, fever and no evidence of volume overload is typical of TRALI. TACO presents with hypertension, raised BNP and response to diuretics.

15. Question 15Transfusion Medicinemedium

    For which recipient are gamma-irradiated cellular blood components required?

    1. AAdult with sickle cell disease
    2. BRecipient of a directed donation from a parent
    3. CPregnant woman who is CMV seronegative at booking
    4. DPatient with selective IgA deficiency
    Show answer and explanation▾

    Answer: B. Recipient of a directed donation from a parent

    Directed donations from blood relatives carry a risk of transfusion-associated graft-versus-host disease because of shared HLA haplotypes, so irradiation is required. IgA deficiency is managed with IgA-deficient or washed products, not irradiation.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.