Chemical Pathology – 26 MCQs | Kenya MBChB

26 Year 3: Hematopathology exam questions on Chemical Pathology for medical students. Includes MCQs, answers, explanations and written questions. Sample: A 35-y

This MCQ set contains 26 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 35-year-old man has no clinical evidence for bleeding and he feels fine. As part of a pre-operative workup for a hernia repair, laboratory studies show Hgb 14.8 g/dL, Hct 45%, MCV 96 fL, WBC count 8500/microliter, and platelet count 275,000/microliter. His prothrombin time is normal, but the parti

  1. A. IX
  2. B. VIII
  3. C. XII
  4. D. X
  5. E. XIII

Correct answer: C – XII

Factor XII deficiency causes prolonged PTT but normal PT, and importantly does not cause clinical bleeding symptoms. This fits the asymptomatic patient with isolated PTT prolongation. ---

Q2: A 20-year-old man is actively bleeding from multiple sites during surgery. He has a CBC that shows a WBC count of 4500/microliter, Hgb 7.6 g/dL, Hct 23.9%, MCV 98 fL, and platelet count 75,000/microliter. His prothrombin time is 30 seconds and partial thromboplastin time 63 seconds. What is the best

  1. A. Cryoprecipitate (Cryo)
  2. B. Packed red blood cells (PRBCs)
  3. C. Granulocytes
  4. D. Fresh frozen plasma (FFP)

Correct answer: A – Cryoprecipitate (Cryo)

The patient has multiple deficiencies: low Hgb/Hct (anemia), low platelets (thrombocytopenia), and prolonged PT/PTT (coagulopathy). Whole blood provides red cells, platelets, and clotting factors all in one product. ---

Q3: A 31-year-old woman has oozing of blood from mucous membranes over the past 3 days. Laboratory studies show a platelet count of 10,000/microliter. She receives 6 units of platelets. An hour following this transfusion, her platelet count is 2,000/microliter. What is the most probable explanation for

  1. A. Anti-HLA antibodies
  2. B. Septicemia
  3. C. Hemorrhage
  4. D. Single donor source

Correct answer: A – Anti-HLA antibodies

The platelet count actually decreased after transfusion, indicating platelet refractoriness most commonly due to anti-HLA antibodies that destroy transfused platelets. ---

Q4: A 12-year-old boy has had multiple episodes of bleeding since infancy. It is characterized by hemarthroses and decreased joint mobility. His prothrombin time (PT) is normal, but the partial thromboplastin time (PTT) is elevated. When his plasma is mixed with normal plasma, the PTT is not elevated. H

  1. A. Congenital HIV infection
  2. B. Repeated trauma
  3. C. Inherited gene mutation
  4. D. Chronic liver disease

Correct answer: C – Inherited gene mutation

Classic presentation of hemophilia (Factor VIII or IX deficiency) with hemarthroses, prolonged PTT that corrects with mixing study, indicating factor deficiency rather than inhibitor. This is caused by inherited gene mutations. ---

Q5: A 64-year-old nursing home patient receiving tube feedings is admitted with fever of two days' duration accompanied by a cough productive of yellowish sputum. On admission his temperature is 37.4°C. A sputum gram stain shows 4+ gram positive diplococci. He is also found to have a total serum protein

  1. A. Chronic renal failure
  2. B. Plasma cell dyscrasia
  3. C. Diabetes mellitus
  4. D. Hepatitis B virus infection

Correct answer: B – Plasma cell dyscrasia

High total protein (9.4 g/dL) with normal albumin (3.8 g/dL) suggests elevated globulins, characteristic of plasma cell disorders like multiple myeloma. The large protein gap (9.4-3.8 = 5.6) is diagnostic. ---

Q6: A 44-year-old man has had congestive heart failure for 2 years. His serum ferritin is markedly elevated. His CBC shows WBC count 6300/microliter, Hgb 7.8 g/dL, Hct 22.6%, MCV 69 fL, and platelet count 177,000/microliter. A hemoglobin electrophoresis reveals 2% Hgb A, 8% Hgb A2, and 90% Hgb F. Which

  1. A. Sickle cell anemia
  2. B. Alpha thalassemia minor
  3. C. Hemoglobin H disease
  4. D. Hereditary persistence of fetal hemoglobin

Correct answer: A – Sickle cell anemia

Very high HgbF (90%), elevated HgbA2 (8%), minimal HgbA (2%), severe microcytic anemia, and iron overload (high ferritin) are classic for beta thalassemia major. ---

Q7: 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. ---

Q8: An 81-year-old previously healthy woman has had a 2 kg weight loss without dieting over the past 2 months. She reports no other problems. On examination there are no abnormal findings. Laboratory studies show a serum alkaline phosphatase of 200 U/L. Which of the following diseases is she most likely

  1. A. Bone metastases
  2. B. Cholelithiasis
  3. C. Intestinal obstruction
  4. D. Osteoporosis

Correct answer: A – Bone metastases

Elderly patient with unexplained weight loss and isolated elevated alkaline phosphatase suggests bone metastases from occult malignancy. ---

Q9: 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. ---

Q10: A 62-year-old healthy woman has a pre-operative workup for an elective surgery. A serum glucose is ordered and is of 120 mg/dl. Four hours later that day, another glucose test is ordered unnecessarily, and the value is noted to be 124 mg/dl. Which of the following best explains the difference in the

  1. A. Laboratory error
  2. B. Lack of test sensitivity
  3. C. Blood removed by phlebotomy
  4. D. Test coefficient of variation

Correct answer: D – Test coefficient of variation

The small difference (4 mg/dL) between two glucose values is within normal analytical variation. Coefficient of variation describes this expected imprecision in laboratory testing. ---

Q11: 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. ---

Q12: A 33-year-old woman has had multiple episodes of deep venous thrombosis over the past year. Last week she had a transient ischemic attack. On examination there are no abnormal findings. Laboratory studies show a prolonged prothrombin and partial thromboplastin time. When her plasma is mixed in a rat

  1. A. Disseminated intravascular coagulopathy
  2. B. Protein C deficiency
  3. C. Vitamin K deficiency
  4. D. Hemophilia B

Correct answer: A – Disseminated intravascular coagulopathy

Recurrent thrombosis, prolonged PT/PTT that don't correct with mixing studies indicates presence of inhibitors (lupus anticoagulant), characteristic of antiphospholipid syndrome. ---

Q13: A 5-year-old previously healthy child develops a mild watery diarrhea that lasts for 3 days. On physical examination the child has a low-grade fever. A stool for ova and parasites is negative. The child recovers without therapy and has no sequelae. What is the most likely infectious etiology for her

  1. A. Adenovirus
  2. B. Vibrio parahemolyticus
  3. C. Rotavirus
  4. D. Salmonella enterica

Correct answer: C – Rotavirus

Self-limited watery diarrhea in a young child with low-grade fever, negative for parasites, is most commonly caused by rotavirus - the leading cause of viral gastroenteritis in children. ---

Q14: 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). ---

Q15: A 30-year-old man experiences excessive bleeding following a wisdom tooth extraction. There is a family history of similar problems. His mother had menorrhagia. His sister has frequent nosebleeds. Laboratory findings show he has a normal PT, PTT, and platelet count. Which of the following coagulatio

  1. A. von Willebrand disease
  2. B. Vitamin K deficiency
  3. C. Hemophilia B
  4. D. Protein C deficiency

Correct answer: A – von Willebrand disease

Family history of bleeding in both males and females, mucosal bleeding pattern, normal PT/PTT/platelet count suggests von Willebrand disease - the most common inherited bleeding disorder. ---

Q16: A 47-year-old man has focal pain and swelling in his mouth for the past month. Physical exam reveals a large, firm area of induration starting from the gingiva and extending to the right floor of the mouth, with draining sinus tracts to skin. Mandibular osteomyelitis is present radiographically. The

  1. A. Thin, branching, septate hyphae
  2. B. Long gram positive filaments
  3. C. Short acid fast bacilli
  4. D. Long acid fast filaments

Correct answer: B – Long gram positive filaments

Chronic osteomyelitis with draining sinuses and yellowish granules (sulfur granules) is characteristic of Actinomyces, which appears as long, branching, gram-positive filaments. ---

Q17: A 34-year-old woman has developed malaise for the past 3 months. Over the past day she has becomes very ill with mental status changes. On examination areas of skin purpura are noted. Laboratory studies show Hgb 9.2, platelet count 225,000, and WBC count 44,500 with 18 segs, 5 bands, 2 metamyelocyte

  1. A. t(8;14)
  2. B. t(9;22)
  3. C. t(14;18)
  4. D. t(11;21)

Correct answer: A – t(8;14)

High percentage of promyelocytes (67%) with acute clinical deterioration and purpura suggests acute promyelocytic leukemia (APL), which is associated with t(15;17) translocation. ---

Q18: A 58-year-old man with a history of unstable angina presents with chest pain that has been worsening for the past eight hours. The pain radiates down his left arm. On examination he is now diaphoretic, with tachycardia and an irregular cardiac rhythm. Which of the following is now the best laborator

  1. A. C-reactive protein
  2. B. Troponin I
  3. C. Total LDH
  4. D. Myoglobin

Correct answer: B – Troponin I

Troponin I is the most specific and sensitive marker for myocardial infarction, remaining elevated for days after the event. It's the gold standard cardiac biomarker. ---

Q19: A 40-year-old veterinarian working near the foothills of the San Gabriel mountains in Southern California saw his physician because of marked axillary and inguinal lymph node swelling developing in only a day. On examination he has a high fever with tender right axillary node. There is a mall lacera

  1. A. Leptospira interrogans
  2. B. Borrelia burgdorferi
  3. C. Yersinia pestis
  4. D. Bacillus anthracis

Correct answer: C – Yersinia pestis

Veterinarian in California with acute lymphadenitis, necrosis, hemorrhage, and gram-negative bacilli suggests plague (Yersinia pestis), which is endemic in California and affects animals and their handlers. ---

Q20: While driving to his next clinic visit, a 52 year old man is involved in a vehicular accident in which his car is struck broadside at an intersection. Though the air bag inflates, the car rolls over, and the impact against the door results in a large laceration to his lower leg. After transport to a

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

Correct answer: A – Packed red blood cells

Severely low hematocrit (16%) indicates massive blood loss requiring immediate red cell replacement. While platelets are also low, the primary need is to restore oxygen-carrying capacity. ---

Q21: 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. ---

Q22: Seven children living in the same neighborhood develop perianal itching, most pronounced at night, over the past week. Their parents don't pay much attention to this until they also develop the same problem. The eggs recovered from the perianal region of affected children are 50 micron, flat, and em

  1. A. Ascaris lumbricoides
  2. B. Trichuris trichiuria
  3. C. Necator americanus
  4. D. Strongyloides stercoralis

Correct answer: A – Ascaris lumbricoides

Perianal itching at night in children with family spread, and characteristic flat, embryonated eggs found in perianal area describes pinworm (Enterobius vermicularis) infection. ---

Q23: A 58-year-old woman has had malaise and a 2 kg weight loss over the past year. Laboratory studies show Hgb 10 g/dL, Hct 30.1%, MCV 88 fL, platelet count 200,000/microliter, and WBC count 7500/microliter. She has a decreased serum iron and total iron binding capacity (TIBC) in association with an inc

  1. A. Autoimmune hemolytic anemia
  2. B. Atrophic gastritis
  3. C. Colonic adenocarcinoma
  4. D. Chronic hepatitis

Correct answer: C – Colonic adenocarcinoma

Anemia of chronic disease pattern (low iron, low TIBC, high ferritin) with weight loss in older adult suggests underlying malignancy, commonly colorectal cancer. ---

Q24: A 27-year-old G3 P2 woman gives birth at 35 weeks gestational age. On examination the infant has marked hydrops fetalis along with generalized icterus. The baby's peripheral blood smear demonstrates numerous nucleated RBC's, and the spun hematocrit is only 20%. Which of the following laboratory test

  1. A. Blood type O positive
  2. B. Hemoglobin C
  3. C. Positive Coombs test
  4. D. Decreased haptoglobin

Correct answer: C – Positive Coombs test

Hydrops fetalis with severe anemia and nucleated RBCs suggests hemolytic disease of the newborn, most commonly due to Rh incompatibility. The mother would have a positive indirect Coombs test. ---

Q25: A 44-year-old man has increasing malaise and swelling of his legs and abdomen for the past year. On exam there is lower leg pitting edema and an abdominal fluid wave. Laboratory studies show an AST of 240 and an ALT of 155 U/L. The total serum bilirubin is 2.4 mg/dL with direct bilirubin of 1.6 mg/d

  1. A. Gilbert disease
  2. B. Chronic alcoholism
  3. C. Acute viral hepatitis
  4. D. Autoimmune hemolytic anemia

Correct answer: B – Chronic alcoholism

Chronic liver disease with ascites, edema, low albumin, elevated transaminases (AST ALT ratio suggests alcoholic liver disease), and low alkaline phosphatase pattern indicates chronic alcoholic liver disease. ---

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