MLS ASCP EXAM RECALL QUESTIONS 2025/2026 UPDATE| COMPREHENSIVE
QUESTIONS AND VERIFIED ANSWERS (COMPLETE SOLUTIONS) ASSURED
SUCCESS|GRADE A+!! (100% ACCURATE) GET IT RIGHT!!
Question 1
When monitoring a patient on Procainamide therapy, which metabolite must also be measured to
ensure therapeutic efficacy and safety?
A) Digoxin
B) N-acetylprocainamide (NAPA)
C) Quinidine
D) Lidocaine
E) Phenobarbital
Correct Answer: B) N-acetylprocainamide (NAPA)
Rationale: Procainamide is metabolized by the liver into its active metabolite, N-
acetylprocainamide (NAPA). Both the parent drug and the metabolite have anti-
arrhythmic activity and potential toxicity; therefore, both levels must be monitored to
assess the patient's clinical status.
Question 2
A fungal culture shows loose clusters of small, spherical microconidia and is positive for urease.
This description is most consistent with which organism?
A) Trichophyton rubrum
B) Microsporum canis
C) Trichophyton mentagrophytes
D) Epidermophyton floccosum
E) Candida albicans
Correct Answer: C) Trichophyton mentagrophytes
Rationale: Trichophyton mentagrophytes is characterized microscopically by its numerous
small, globose (spherical) microconidia in grape-like clusters. A key biochemical
differentiator from T. rubrum is that T. mentagrophytes is urease positive and produces a
positive hair perforation test.
Question 3
Which tumor marker is most specifically associated with the diagnosis and monitoring of
choriocarcinoma?
A) CEA
B) CA-125
C) BHCG (Beta-human chorionic gonadotropin)
D) AFP
E) PSA
Correct Answer: C) chorocarcinoma
Rationale: While BHCG is primarily used for pregnancy testing, it serves as a highly
sensitive tumor marker for gestational trophoblastic disease, such as choriocarcinoma and
hydatidiform moles, as well as certain germ cell tumors.
, 2
Question 4
A 24-hour urine collection for 5-HIAA (5-hydroxyindoleacetic acid) is often used to diagnose
which of the following?
A) Pheochromocytoma
B) Carcinoid tumors
C) Multiple myeloma
D) Nephrotic syndrome
E) Wilson's disease
Correct Answer: B) carcinoid tumors
Rationale: 5-HIAA is the primary metabolite of serotonin. Carcinoid tumors, particularly
those of the small intestine, often secrete excessive amounts of serotonin, leading to elevated
levels of 5-HIAA in the urine.
Question 5
Which biochemical test can rapidly differentiate Proteus vulgaris from Proteus mirabilis?
A) Urease
B) Citrate
C) Indole
D) H2S production
E) Motility
Correct Answer: C) P. vulgaris is indole pos. P. mirabilis is indole neg
Rationale: Both species are rapid urease producers and swarming GNRs. However, P.
vulgaris possesses the enzyme tryptophanase and is indole positive, whereas P. mirabilis is
indole negative.
Question 6
Hydatid cyst fluid is used in the blood bank laboratory to neutralize which of the following
antibodies?
A) Anti-K
B) Anti-P1
C) Anti-Lea
D) Anti-Fya
E) Anti-D
Correct Answer: B) used to neutralize Anti-P1 antibody
Rationale: P1 substance is found in nature, including hydatid cyst fluid (from Echinococcus
granulosus). Adding this fluid to a serum containing Anti-P1 will neutralize the antibody,
allowing the technologist to identify other underlying clinically significant antibodies.
Question 7
A patient presents with symptoms suggesting an antacid overdose (specifically magnesium-
based). Which lab value should be monitored most closely?
, 3
A) Sodium
B) Blood pH
C) Bilirubin
D) Hemoglobin
E) Cholesterol
Correct Answer: B) Check pH
Rationale: Antacid overdose (Metabolic Alkalosis) results from the ingestion of large
amounts of bases. Checking the blood pH and bicarbonate levels is essential to assess the
severity of the alkalosis.
Question 8
A PT, PTT, and Thrombin Time are all significantly prolonged on a sample collected from a
central line. What is the most likely cause?
A) Factor VII deficiency
B) Vitamin K deficiency
C) Heparin contamination
D) Lipemia
E) Improper mixing
Correct Answer: C) heparin contamination
Rationale: Central lines are often "flushed" with heparin to prevent clotting. If the line is
not adequately cleared before drawing a coagulation sample, the heparin will contaminate
the tube, causing a dramatic prolongation of all clot-based assays, especially the Thrombin
Time.
Question 9
A mixing study is performed on a patient with a prolonged PTT. The PTT remains prolonged
after mixing the patient's plasma with normal pooled plasma. Which test is indicated next?
A) Bleeding time
B) Fibrinogen assay
C) DRVVT (Dilute Russell Viper Venom Test)
D) Factor VIII assay
E) Reticulocyte count
Correct Answer: C) DRVVT (Dilute Russell Viper Venom Test)
Rationale: Failure to correct a prolonged PTT in a mixing study suggests the presence of an
inhibitor rather than a factor deficiency. The DRVVT is used to detect Lupus
Anticoagulant, a common non-specific inhibitor.
Question 10
In an automated coagulation analyzer, the PT results are consistently normal, but the PTT results
for multiple patients are significantly prolonged. What should be investigated first?
A) The blood pump speed
, 4
B) The CaCl2 and phospholipid reagent delivery
C) The centrifuge speed
D) The patient's diet
E) The incubator temperature
Correct Answer: B) check the CaCl/phospholipid reagent delivery
Rationale: Since the PT is normal (measuring the extrinsic pathway), the common reagents
(like thrombin/thromboplastin) are likely fine. The PTT (intrinsic pathway) requires
specific phospholipids and Calcium Chloride. A delivery failure in these specific reagents
would isolate the problem to the PTT results.
Question 11
A patient is started on Coumadin (Warfarin) therapy. Which of the following proteins will show a
decrease shortly after therapy begins?
A) Albumin
B) Protein C
C) Fibrinogen
D) Haptoglobin
E) Hemoglobin
Correct Answer: B) Decreased protein C
Rationale: Coumadin inhibits the Vitamin K-dependent factors (II, VII, IX, X) and the
natural anticoagulants Protein C and Protein S. Because Protein C has a very short half-
life (approx. 6 hours), it decreases faster than most procoagulant factors.
Question 12
The presence of numerous stomatocytes on a peripheral blood smear is most commonly
associated with:
A) Iron deficiency
B) Uremia
C) Liver disease
D) Sickle cell anemia
E) Lead poisoning
Correct Answer: C) Liver disease
Rationale: Stomatocytes (mouth cells) are erythrocytes with a slit-like area of central pallor.
They are frequently seen in chronic liver disease, alcoholism, and certain hereditary
conditions.
Question 13
Which red cell morphology is a characteristic finding in patients with uremia or renal failure?
A) Spherocytes
B) Target cells
C) Burr cells (Echinocytes)
QUESTIONS AND VERIFIED ANSWERS (COMPLETE SOLUTIONS) ASSURED
SUCCESS|GRADE A+!! (100% ACCURATE) GET IT RIGHT!!
Question 1
When monitoring a patient on Procainamide therapy, which metabolite must also be measured to
ensure therapeutic efficacy and safety?
A) Digoxin
B) N-acetylprocainamide (NAPA)
C) Quinidine
D) Lidocaine
E) Phenobarbital
Correct Answer: B) N-acetylprocainamide (NAPA)
Rationale: Procainamide is metabolized by the liver into its active metabolite, N-
acetylprocainamide (NAPA). Both the parent drug and the metabolite have anti-
arrhythmic activity and potential toxicity; therefore, both levels must be monitored to
assess the patient's clinical status.
Question 2
A fungal culture shows loose clusters of small, spherical microconidia and is positive for urease.
This description is most consistent with which organism?
A) Trichophyton rubrum
B) Microsporum canis
C) Trichophyton mentagrophytes
D) Epidermophyton floccosum
E) Candida albicans
Correct Answer: C) Trichophyton mentagrophytes
Rationale: Trichophyton mentagrophytes is characterized microscopically by its numerous
small, globose (spherical) microconidia in grape-like clusters. A key biochemical
differentiator from T. rubrum is that T. mentagrophytes is urease positive and produces a
positive hair perforation test.
Question 3
Which tumor marker is most specifically associated with the diagnosis and monitoring of
choriocarcinoma?
A) CEA
B) CA-125
C) BHCG (Beta-human chorionic gonadotropin)
D) AFP
E) PSA
Correct Answer: C) chorocarcinoma
Rationale: While BHCG is primarily used for pregnancy testing, it serves as a highly
sensitive tumor marker for gestational trophoblastic disease, such as choriocarcinoma and
hydatidiform moles, as well as certain germ cell tumors.
, 2
Question 4
A 24-hour urine collection for 5-HIAA (5-hydroxyindoleacetic acid) is often used to diagnose
which of the following?
A) Pheochromocytoma
B) Carcinoid tumors
C) Multiple myeloma
D) Nephrotic syndrome
E) Wilson's disease
Correct Answer: B) carcinoid tumors
Rationale: 5-HIAA is the primary metabolite of serotonin. Carcinoid tumors, particularly
those of the small intestine, often secrete excessive amounts of serotonin, leading to elevated
levels of 5-HIAA in the urine.
Question 5
Which biochemical test can rapidly differentiate Proteus vulgaris from Proteus mirabilis?
A) Urease
B) Citrate
C) Indole
D) H2S production
E) Motility
Correct Answer: C) P. vulgaris is indole pos. P. mirabilis is indole neg
Rationale: Both species are rapid urease producers and swarming GNRs. However, P.
vulgaris possesses the enzyme tryptophanase and is indole positive, whereas P. mirabilis is
indole negative.
Question 6
Hydatid cyst fluid is used in the blood bank laboratory to neutralize which of the following
antibodies?
A) Anti-K
B) Anti-P1
C) Anti-Lea
D) Anti-Fya
E) Anti-D
Correct Answer: B) used to neutralize Anti-P1 antibody
Rationale: P1 substance is found in nature, including hydatid cyst fluid (from Echinococcus
granulosus). Adding this fluid to a serum containing Anti-P1 will neutralize the antibody,
allowing the technologist to identify other underlying clinically significant antibodies.
Question 7
A patient presents with symptoms suggesting an antacid overdose (specifically magnesium-
based). Which lab value should be monitored most closely?
, 3
A) Sodium
B) Blood pH
C) Bilirubin
D) Hemoglobin
E) Cholesterol
Correct Answer: B) Check pH
Rationale: Antacid overdose (Metabolic Alkalosis) results from the ingestion of large
amounts of bases. Checking the blood pH and bicarbonate levels is essential to assess the
severity of the alkalosis.
Question 8
A PT, PTT, and Thrombin Time are all significantly prolonged on a sample collected from a
central line. What is the most likely cause?
A) Factor VII deficiency
B) Vitamin K deficiency
C) Heparin contamination
D) Lipemia
E) Improper mixing
Correct Answer: C) heparin contamination
Rationale: Central lines are often "flushed" with heparin to prevent clotting. If the line is
not adequately cleared before drawing a coagulation sample, the heparin will contaminate
the tube, causing a dramatic prolongation of all clot-based assays, especially the Thrombin
Time.
Question 9
A mixing study is performed on a patient with a prolonged PTT. The PTT remains prolonged
after mixing the patient's plasma with normal pooled plasma. Which test is indicated next?
A) Bleeding time
B) Fibrinogen assay
C) DRVVT (Dilute Russell Viper Venom Test)
D) Factor VIII assay
E) Reticulocyte count
Correct Answer: C) DRVVT (Dilute Russell Viper Venom Test)
Rationale: Failure to correct a prolonged PTT in a mixing study suggests the presence of an
inhibitor rather than a factor deficiency. The DRVVT is used to detect Lupus
Anticoagulant, a common non-specific inhibitor.
Question 10
In an automated coagulation analyzer, the PT results are consistently normal, but the PTT results
for multiple patients are significantly prolonged. What should be investigated first?
A) The blood pump speed
, 4
B) The CaCl2 and phospholipid reagent delivery
C) The centrifuge speed
D) The patient's diet
E) The incubator temperature
Correct Answer: B) check the CaCl/phospholipid reagent delivery
Rationale: Since the PT is normal (measuring the extrinsic pathway), the common reagents
(like thrombin/thromboplastin) are likely fine. The PTT (intrinsic pathway) requires
specific phospholipids and Calcium Chloride. A delivery failure in these specific reagents
would isolate the problem to the PTT results.
Question 11
A patient is started on Coumadin (Warfarin) therapy. Which of the following proteins will show a
decrease shortly after therapy begins?
A) Albumin
B) Protein C
C) Fibrinogen
D) Haptoglobin
E) Hemoglobin
Correct Answer: B) Decreased protein C
Rationale: Coumadin inhibits the Vitamin K-dependent factors (II, VII, IX, X) and the
natural anticoagulants Protein C and Protein S. Because Protein C has a very short half-
life (approx. 6 hours), it decreases faster than most procoagulant factors.
Question 12
The presence of numerous stomatocytes on a peripheral blood smear is most commonly
associated with:
A) Iron deficiency
B) Uremia
C) Liver disease
D) Sickle cell anemia
E) Lead poisoning
Correct Answer: C) Liver disease
Rationale: Stomatocytes (mouth cells) are erythrocytes with a slit-like area of central pallor.
They are frequently seen in chronic liver disease, alcoholism, and certain hereditary
conditions.
Question 13
Which red cell morphology is a characteristic finding in patients with uremia or renal failure?
A) Spherocytes
B) Target cells
C) Burr cells (Echinocytes)
