Medical Laboratory Technician Exam ASCP Medical Laboratory Technician 1

Question 1

A urine specimen tested by dipstick shows a positive result for blood but microscopic examination reveals no red blood cells. Which condition best explains this discrepancy?

Accepted Answer

Myoglobinuria from rhabdomyolysis

Answer

Dipstick blood reagent pads react with hemoglobin AND myoglobin due to their shared peroxidase-like activity. Myoglobinuria (from muscle breakdown) produces a positive dipstick without intact RBCs on microscopy, distinguishing it from true hematuria.

Question 2

A technician performs a reticulocyte count using new methylene blue stain and counts 25 reticulocytes per 1,000 red blood cells. In a patient with a hematocrit of 25%, what is the corrected reticulocyte count (CRC)?

Accepted Answer

1.1%

Answer

The CRC corrects for anemia using the formula: CRC = reticulocyte % × (patient Hct / normal Hct). With 2.5% reticulocytes and Hct of 25% vs. normal 45%: 2.5 × (25/45) = 1.1%. This prevents overestimating erythropoietic activity in anemic patients.

Question 3

Which culture medium is both selective and differential, used to isolate gram-negative enteric organisms while distinguishing lactose fermenters from non-fermenters?

Accepted Answer

MacConkey agar

Answer

MacConkey agar contains crystal violet and bile salts that inhibit gram-positive organisms (selective) and lactose with pH indicator neutral red that turns colonies pink-red when lactose is fermented (differential). Non-fermenters such as Salmonella and Shigella appear colorless.

Question 4

A serum protein electrophoresis shows a tall, narrow spike in the gamma region. Which laboratory finding would most support a diagnosis of multiple myeloma?

Accepted Answer

Bence Jones proteins in urine and rouleaux formation on peripheral smear

Answer

Multiple myeloma is characterized by a monoclonal (M) protein spike, and malignant plasma cells often secrete free immunoglobulin light chains (Bence Jones proteins) detectable in urine. The excess immunoglobulins also cause RBCs to stack (rouleaux), seen on peripheral blood smear.

Question 5

During ABO blood grouping, a patient's red cells react with anti-A but not anti-B, while the patient's serum agglutinates B cells but not A cells. What blood type does this confirm?

Accepted Answer

Type A

Answer

ABO typing uses forward (cell) and reverse (serum) grouping. Cells reacting with anti-A only indicates A antigen is present. The serum agglutinating B cells confirms the presence of anti-B antibody, consistent with blood type A. Both results must agree before reporting.

Medical Laboratory Technician Exam Practice Test

Medical Laboratory Technician Exam Practice Test

Medical Laboratory Technician Exam ASCP Medical Laboratory Technician 1