Chemical Pathology – 5 MCQs | Kenya MBChB

5 Year 3: Hematopathology exam questions on Chemical Pathology for medical students. Includes MCQs, answers, explanations and written questions. Sample: A study

This MCQ set contains 5 questions on Chemical Pathology in the Year 3: Hematopathology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: A study of blood product therapy is done. One product is identified that carries the greatest risk for infection. This blood product has the shortest shelf life, and it must be used as quickly as possible for transfusion. Which of the following products is best described by these findings? Options:

  1. A. Whole blood
  2. B. Packed red blood cells
  3. C. Cryoprecipitate
  4. D. Fresh frozen plasma

Correct answer: A – Whole blood

Platelets are stored at room temperature (not refrigerated), have the shortest shelf life (5 days), and highest bacterial contamination risk due to room temperature storage. ---

Q2: A 17-year-old boy has developed a mild fever with sore throat over the past day. On physical examination he has generalized lymphadenopathy. Laboratory studies show a CD4 lymphocyte count of 375/microliter. He is most likely to be infected with which of the following agents? Options: A) HTLV-1

  1. A. HTLV-2
  2. B. HIV-1
  3. C. HIV-2
  4. D. HHV-8

Correct answer: A – HTLV-2

HTLV-1 can cause adult T-cell leukemia/lymphoma with lymphadenopathy and can affect CD4 counts. The acute presentation with lymphadenopathy fits HTLV-1 infection better than the other options. ---

Q3: A healthy 27 year old male donates blood. He completes the questionnaire and interview with no exclusions noted. The presence of which of the following infectious agents will not routinely tested for on his blood collected for transfusion? Options: A) Human immunodeficiency virus type 1

  1. A. Hepatitis A virus
  2. B. Human T lymphocytotrophic virus
  3. C. Treponema pallidum
  4. D. Hepatitis C virus

Correct answer: A – Hepatitis A virus

Hepatitis A is not routinely tested in blood donors because it's primarily fecal-oral transmission, has short viremic period, and doesn't cause chronic infection. All other agents are routinely screened. ---

Q4: During phlebotomy, there is difficulty obtaining blood for all of the test ordered. Not all of the collection tubes are completely filled. Of the following collection tubes, which is the only one that may be partially filled and not affect test results? Options: A) Gray top for glucose

  1. A. Light-blue top for protime
  2. B. Purple top for CBC
  3. C. Black top for sed rate
  4. D. Red top for total protein

Correct answer: D – Red top for total protein

Red top tubes (serum tubes) don't contain anticoagulants, so the blood-to-additive ratio isn't critical. Other tubes require specific ratios for accurate results (especially coagulation studies). ---

Q5: A 25-year-old woman incurs a head injury from a skiing accident. She is now in stable condition and her vital signs are normal. Serum electrolytes now show Na 134 meq/L, K 7.6 meq/L, Cl 100 meq/L, and CO2 25 meq/L. What is the most likely etiology for these laboratory test findings? Options: A) Hemo

  1. A. Severe diarrhea
  2. B. Mannitol infusion
  3. C. Acute renal failure
  4. D. Excess intravenous fluids

Correct answer: A – Severe diarrhea

Stable patient with markedly elevated potassium (7.6) but normal other electrolytes suggests pseudohyperkalemia from hemolysis during blood collection, releasing intracellular potassium. ---

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