American Board of Pathology (ABPath) Clinical Pathology Certification Exam — Questions and Answers

Question 1: A febrile patient returning from sub-Saharan Africa has ring forms and banana-shaped gametocytes on blood smear. Diagnosis?

Plasmodium vivax
Trypanosoma brucei
Babesia microti
Plasmodium falciparum (Correct answer)

Correct answer: Plasmodium falciparum

Crescent/banana-shaped gametocytes are characteristic of P. falciparum.

Question 2: Which marker is a sensitive indicator of vascular/endothelial differentiation?

CK7
CDX2
CD31 (Correct answer)
GFAP

Correct answer: CD31

CD31 is a highly specific and sensitive endothelial marker used in vascular tumors.

Question 3: A 68-year-old male with a history of myelodysplastic syndrome receives a transfusion of 2 units of packed red blood cells. Five days later, he presents with a low-grade fever, mild jaundice, and a greater than expected drop in his hemoglobin level. A direct antiglobulin test (DAT) is now positive. Which of the following is the most likely cause of this presentation?

Transfusion-associated graft-versus-host disease (TA-GVHD)
Delayed hemolytic transfusion reaction (Correct answer)
Acute hemolytic transfusion reaction
Febrile non-hemolytic transfusion reaction

Correct answer: Delayed hemolytic transfusion reaction

The patient's presentation of symptoms such as fever and jaundice several days after a transfusion, along with a positive DAT and unexpected anemia, is characteristic of a delayed hemolytic transfusion reaction (DHTR). [8, 15] This reaction occurs when a patient has been previously sensitized to a red blood cell antigen and has an anamnestic antibody response upon re-exposure through transfusion. [26] Acute reactions occur within 24 hours, TA-GVHD has different primary symptoms, and febrile reactions typically do not involve hemolysis or a positive DAT.

Question 4: Healing by primary intention (first intention) is characteristic of:

An abscess cavity
A clean surgical incision with approximated edges (Correct answer)
A large open wound with tissue loss
A chronic diabetic ulcer

Correct answer: A clean surgical incision with approximated edges

Primary intention healing occurs in clean wounds with closely apposed edges, requiring minimal granulation tissue.

Question 5: A patient with hemolyzed serum will show a falsely increased value for which analyte?

Bicarbonate
Albumin
Sodium
Potassium (Correct answer)

Correct answer: Potassium

Red cells are rich in potassium, so hemolysis releases it into serum and elevates the measured value.

Question 6: Which finding best confirms a diagnosis of diabetes mellitus in an asymptomatic patient?

Random glucose of 150 mg/dL
Single HbA1c of 6.0%
Fasting glucose of 115 mg/dL
HbA1c of 6.8% confirmed on repeat testing (Correct answer)

Correct answer: HbA1c of 6.8% confirmed on repeat testing

An HbA1c ≥6.5% confirmed on a separate occasion meets diagnostic criteria for diabetes.

Question 7: A villous adenoma of the rectum is associated with highest risk for malignant transformation compared to other polyp types because it has:

Microsatellite instability
Submucosal invasion at presentation
Highest density of goblet cells
Largest surface area with maximal dysplasia exposure (Correct answer)

Correct answer: Largest surface area with maximal dysplasia exposure

Villous adenomas have the greatest malignant potential (up to 40%) due to their larger size, greater surface area, and higher degree of dysplasia at diagnosis.

Question 8: Delta checks are used primarily to detect:

Instrument temperature drift
Significant changes in a patient's result compared to prior results, flagging possible errors (Correct answer)
Reagent expiration
Staff scheduling conflicts

Correct answer: Significant changes in a patient's result compared to prior results, flagging possible errors

A delta check compares a current result to the patient's previous value to catch specimen mix-ups or errors.

Question 9: In a non-ulcerated melanoma, Breslow thickness is measured from:

The base of the epidermis to the base of the tumor
The skin surface to the deepest tumor cell
The dermal-epidermal junction to the deepest tumor cell
The granular layer to the deepest tumor cell (Correct answer)

Correct answer: The granular layer to the deepest tumor cell

Breslow thickness is measured from the top of the granular layer (or the base of an ulcer if ulcerated) to the deepest invasive tumor cell.

Question 10: Direct immunofluorescence (DIF) in dermatitis herpetiformis characteristically shows:

Linear IgG along the basement membrane zone
IgM deposits around superficial blood vessels
Intercellular IgG in a fish-net pattern
Granular IgA deposits in the dermal papillae (Correct answer)

Correct answer: Granular IgA deposits in the dermal papillae

Dermatitis herpetiformis shows granular IgA deposits in the tips of the dermal papillae on DIF, reflecting tissue transglutaminase autoantibody deposition in this gluten-sensitive dermatosis.

Question 11: The Philadelphia chromosome results from which translocation?

t(15;17)(q22;q12)
t(9;22)(q34;q11) (Correct answer)
t(14;18)(q32;q21)
t(8;14)(q24;q32)

Correct answer: t(9;22)(q34;q11)

t(9;22) fuses BCR and ABL1, producing the Philadelphia chromosome in CML and some ALL.

Question 12: Which fungus is identified by broad, ribbon-like, aseptate hyphae with wide-angle branching?

Cryptococcus neoformans
Aspergillus
Mucor (Zygomycetes) (Correct answer)
Candida albicans

Correct answer: Mucor (Zygomycetes)

Mucormycosis shows broad aseptate hyphae branching at wide (~90°) angles.

Question 13: A patient's serum reacts with all reagent red cells in an antibody panel including the autocontrol. What is the most likely cause?

Rouleaux only
A single low-frequency antibody
A warm autoantibody (Correct answer)
Anti-K alloantibody

Correct answer: A warm autoantibody

Pan-reactivity with a positive autocontrol typically indicates a warm autoantibody.

Question 14: The direct antiglobulin test (DAT) detects which of the following?

Antibody or complement bound to red cells in vivo (Correct answer)
Platelet antibodies
Free antibody in the patient's serum
Fibrin degradation products

Correct answer: Antibody or complement bound to red cells in vivo

The DAT detects immunoglobulin or complement already coating red cells in vivo.

Question 15: A patient with chronic gastroesophageal reflux develops columnar epithelium with goblet cells in the distal esophagus. This is termed?

Achalasia
Esophageal varices
Barrett esophagus (Correct answer)
Squamous metaplasia

Correct answer: Barrett esophagus

Barrett esophagus is intestinal metaplasia of the esophageal lining, a risk factor for adenocarcinoma.

Question 16: The Philadelphia chromosome, t(9;22) BCR-ABL fusion, is most characteristic of which condition?

Acute promyelocytic leukemia
Follicular lymphoma
Chronic myelogenous leukemia (Correct answer)
Multiple myeloma

Correct answer: Chronic myelogenous leukemia

The t(9;22) BCR-ABL Philadelphia chromosome defines chronic myelogenous leukemia.

Question 17: A patient's tumor shows microsatellite instability (MSI-high). Which pathway defect is most directly responsible?

Nucleotide excision repair defect
Homologous recombination deficiency
Base excision repair defect
DNA mismatch repair deficiency (Correct answer)

Correct answer: DNA mismatch repair deficiency

MSI results from loss of DNA mismatch repair function, commonly involving MLH1, MSH2, MSH6, or PMS2.

Question 18: A patient with high PTH, low calcium, and high phosphate most likely has which condition?

Vitamin D toxicity
Hypoparathyroidism
Primary hyperparathyroidism
Chronic kidney disease (secondary hyperparathyroidism) (Correct answer)

Correct answer: Chronic kidney disease (secondary hyperparathyroidism)

Renal failure retains phosphate and lowers calcium, driving compensatory secondary hyperparathyroidism.

Question 19: Which serologic marker indicates immunity to hepatitis B after vaccination?

Anti-HBc IgM
Anti-HBs antibody (Correct answer)
HBsAg
HBeAg

Correct answer: Anti-HBs antibody

Anti-HBs is the protective antibody present after vaccination or recovery.

Question 20: Serous inflammation is best exemplified by:

A fibrinous pericarditis
A skin blister with clear fluid (Correct answer)
A pus-filled abscess
A caseating granuloma

Correct answer: A skin blister with clear fluid

Serous inflammation involves outpouring of thin, protein-poor fluid, as seen in a skin blister.

Question 21: A lung biopsy from a severely immunocompromised patient with a pulmonary nodule is examined. Microscopic evaluation reveals fungal elements consisting of septate hyphae that branch at acute, 45-degree angles. This morphological finding is most characteristic of which of the following organisms?

Mucor species
Cryptococcus neoformans
Aspergillus fumigatus (Correct answer)
Candida albicans

Correct answer: Aspergillus fumigatus

The presence of septate hyphae with acute-angle (approximately 45-degree) branching is a classic histopathologic feature of Aspergillus species. In contrast, Mucor species (Zygomycetes) are characterized by broad, pauciseptate or non-septate hyphae with right-angle branching. Cryptococcus neoformans is an encapsulated yeast, and Candida albicans typically appears as budding yeasts and pseudohyphae.

Question 22: Which of the following infectious agents is NOT universally tested for on all allogeneic blood donations in the United States?

Hepatitis B Virus (HBV)
Hepatitis C Virus (HCV)
Cytomegalovirus (CMV) (Correct answer)
Human Immunodeficiency Virus (HIV)

Correct answer: Cytomegalovirus (CMV)

While all blood donations in the U.S. are tested for a panel of infectious agents including HIV, HCV, HBV, and others, Cytomegalovirus (CMV) testing is not performed on every unit. [9, 12, 23] CMV testing is typically performed on a subset of donations to provide CMV-seronegative products for specific at-risk patient populations, such as premature infants and transplant recipients.

Question 23: A child has a barking cough and inspiratory stridor. Which virus is the most common cause?

Respiratory syncytial virus
Influenza A
Adenovirus
Parainfluenza virus (Correct answer)

Correct answer: Parainfluenza virus

Parainfluenza virus is the leading cause of croup (laryngotracheobronchitis).

Question 24: In the ABO system, which individual is the universal plasma donor?

Group A
Group O
Group B
Group AB (Correct answer)

Correct answer: Group AB

Group AB plasma lacks anti-A and anti-B, making it the universal plasma donor.

Question 25: A biopsy showing non-caseating granulomas in the lung and hilar lymph nodes without organisms most suggests?

Aspergillosis
Sarcoidosis (Correct answer)
Tuberculosis
Squamous cell carcinoma

Correct answer: Sarcoidosis

Sarcoidosis classically produces non-caseating granulomas with negative stains for organisms.

Question 26: Smudge cells on a peripheral smear are an artifact classically over-represented in:

Acute myeloid leukemia
Polycythemia vera
Chronic lymphocytic leukemia (Correct answer)
Aplastic anemia

Correct answer: Chronic lymphocytic leukemia

Fragile CLL lymphocytes rupture during smear preparation, producing smudge cells.

Question 27: What is the expected corrected count increment purpose when transfusing platelets?

To measure red cell survival
To evaluate fibrinogen levels
To check for ABO antibodies
To assess platelet transfusion response and detect refractoriness (Correct answer)

Correct answer: To assess platelet transfusion response and detect refractoriness

The corrected count increment evaluates the platelet response and identifies refractoriness.

Question 28: Which cell type predominates in a chronic inflammatory infiltrate along with lymphocytes and plasma cells?

Macrophages (Correct answer)
Neutrophils
Erythrocytes
Mast cells

Correct answer: Macrophages

Macrophages, lymphocytes, and plasma cells characterize chronic inflammation.

Question 29: Aschoff bodies are pathognomonic of which condition?

Infective endocarditis
Acute rheumatic fever (Correct answer)
Cardiac amyloidosis
Dilated cardiomyopathy

Correct answer: Acute rheumatic fever

Aschoff bodies with Anitschkow cells are diagnostic of rheumatic myocarditis.

Question 30: Which organism produces a green pigment (pyocyanin) and a grape-like odor in culture?

Proteus mirabilis
Pseudomonas aeruginosa (Correct answer)
Escherichia coli
Klebsiella pneumoniae

Correct answer: Pseudomonas aeruginosa

P. aeruginosa produces pyocyanin and a fruity/grape-like odor.

Question 31: A febrile nonhemolytic transfusion reaction is most commonly caused by which mechanism?

Bacterial contamination
ABO incompatibility
Cytokines from donor leukocytes and recipient antibodies to leukocytes (Correct answer)
IgA deficiency

Correct answer: Cytokines from donor leukocytes and recipient antibodies to leukocytes

FNHTRs result from accumulated cytokines and recipient anti-leukocyte antibodies.

American Board of Pathology (ABPath) Clinical Pathology Certification Exam

The ABPath Clinical Pathology exam certifies physicians in laboratory medicine, covering hematopathology, blood banking/transfusion medicine, medical microbiology, chemical pathology, and laboratory management across a full-day computer-based examination.

Questions

36 min

Time Limit

70%

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