Chemical Pathology | MCQ Quiz | OmpathStudy Kenya

Question 1

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 partial thromboplastin time is prolonged. A deficiency of which of the following coagulation factors is most likely be associated with these findings? Options

Accepted Answer

XIII — 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. ---

Question 2

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 blood product to use for him in this situation? Options: A) Whole blood

Accepted Answer

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. ---

Question 3

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 the change in pre- to post-transfusion platelet count? Options: A) Splenomegaly

Accepted Answer

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

Question 4

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. His platelet count is normal. Which of the following is the most likely cause for his illness? Options: A) Acquired autoantibody

Accepted Answer

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. ---

Question 5

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 of 9.4 g/dl with serum albumin of 3.8 g/dl. Which of the following underlying diseases do these findings most strongly suggest that he has? Options: A) Chronic obstructive pulmonary disease

Accepted Answer

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. ---

Question 6

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 of the following hematologic conditions is he most likely to have? Options: A) Beta thalassemia major

Accepted Answer

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. ---

Question 7

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: A) Platelets

Accepted Answer

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. ---

Question 8

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 to have? Options: A) Acute viral hepatitis

Accepted Answer

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

Question 9

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

Accepted Answer

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. ---

Question 10

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 these two values on this woman? Options: A) Diabetes mellitus

Accepted Answer

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. ---

Question 11

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

Accepted Answer

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. ---

Question 12

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 ratio of 1:1 with normal plasma, neither the PT nor the PTT normalize. Which of the following conditions is she most likely to have? Options: A) Antiphospholipid syndrome

Accepted Answer

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. ---

Question 13

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 diarrheal illness? Options: A) Shigella flexneri

Accepted Answer

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. ---

Question 14

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

Accepted Answer

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). ---

Question 15

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 coagulation disorders is this man most likely to have? Options: A) Antiphospholipid antibody

Accepted Answer

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. ---

Question 16

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. There is some granular, yellowish-orange material in the exudate. Which of the following findings on a smear of the exudate is most likely to be seen microscopically? Options: A) Short, broad, non-septate hyphae

Accepted Answer

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. ---

Question 17

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 metamyelocytes, 1 myelocytes, 67 promyelocytes, 5 lymphs, and 2 monos. A bone marrow biopsy shows myeloid hyperplasia with <5% blasts. Which of the following karyotypic findings is most likely present in cells from her biopsy? Options: A) t(15;17)

Accepted Answer

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. ---

Question 18

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 laboratory test to order for this man? Options: A) CK-MB

Accepted Answer

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. ---

Question 19

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 laceration on his right hand. A lymph node biopsy is obtained and shows marked necrosis with hemorrhage, and a Gram stain shows numerous gram-negative bacilli. With which of the following organisms is he most likely infected? Options: A) Francisella tularensis

Accepted Answer

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. ---

Question 20

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 local hospital, he is found to have a Hct of 16%. Coagulation studies reveal a protime of 16 seconds and partial thromboplastin time of 24 seconds. His platelet count is 69,000/microliter. Which of the following blood products is most indicated for treatment of this man? Options: A) Platelet packs

Accepted Answer

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. ---

Question 21

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) Hemolyzed specimen

Accepted Answer

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

Question 22

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 embryonated. Which of the following infections are they most likely to have? Options: A) Enterobius vermicularis

Accepted Answer

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. ---

Question 23

A 45-year-old woman undergoes mitral valve replacement with a bileaflet tilting disk mechanical prosthesis as treatment for chronic rheumatic valvulitis with mitral stenosis. She is prescribed warfarin and the dosage is adjusted based upon prothrombin time testing. Which of the following ranges for international normalized ratio (INR) is most appropriate for this woman? Options: A) 3 to 4

Accepted Answer

2 to 3 — For mechanical heart valves, the target INR is typically 2.5-3.5, but 2-3 is the most appropriate range listed. This provides adequate anticoagulation while minimizing bleeding risk. ---

Question 24

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 increased serum ferritin. Which of the following conditions is she most likely to have? Options: A) Sickle cell anemia

Accepted Answer

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. ---

Question 25

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 findings is most likely to be present in the mother of this infant? Options: A) Antiphospholipid antibodies

Accepted Answer

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. ---

Question 26

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/dL. His serum alkaline phosphatase is 55 U/L. The serum albumin is 2.6 g/dL with total serum protein of 4.9 g/dL. The serum lipase is 72 U/L. Which of the following diseases is he most likely to have? Options: A) Chronic pancreatitis

Accepted Answer

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. ---

Question 27

A 20-year-old woman is involved in a motor vehicle accident and has multiple bone fractures. On arrival in the emergency department her blood pressure is normal, with no orthostatic hypotension. her hematocrit is 27.4% after receiving crystalloids. Her platelet count is 115,000/microliter. Her partial thromboplastin time is 22 seconds and prothrombin time 15 seconds. Which of the following is the most appropriate treatment strategy for this woman? Options: A) Transfuse 2 units of packed RBC's

Accepted Answer

Not give a transfusion — Patient is hemodynamically stable with normal vital signs, hematocrit 25% (acceptable for young healthy patient), normal coagulation studies, and adequate platelet count. No immediate transfusion needed.

Chemical Pathology | MCQ Quiz | OmpathStudy Kenya

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