MLPAO Core Laboratory Procedures Questions and Answers 2

Question 1

What is the purpose of centrifugation in specimen processing in a medical laboratory?

Accepted Answer

To separate blood into its cellular and liquid components

Answer

Centrifugation uses centrifugal force to separate blood into its components: packed red cells at the bottom, a buffy coat of white cells and platelets, and serum or plasma on top.

Question 2

What does the term 'hemolysis' mean in the context of laboratory specimen quality?

Accepted Answer

Rupture of red blood cells releasing hemoglobin into the plasma/serum

Answer

Hemolysis refers to rupture of red blood cell membranes with release of intracellular contents including hemoglobin into the serum or plasma, causing a pink or red discolouration.

Question 3

In clinical chemistry, what is a 'blank' in the context of spectrophotometric analysis?

Accepted Answer

A solution containing all reagents but no analyte, used to zero the instrument

Answer

A blank (or reagent blank) contains all assay reagents but no analyte. It is used to zero the spectrophotometer, accounting for background absorbance from reagents and the cuvette.

Question 4

What is the principle of the Gram stain in clinical microbiology?

Accepted Answer

Differentiates bacteria based on cell wall composition into Gram-positive (purple) and Gram-negative (pink) groups

Answer

The Gram stain differentiates bacteria based on peptidoglycan cell wall thickness: Gram-positive bacteria retain crystal violet (appear purple); Gram-negative bacteria lose it and take up safranin counterstain (appear pink/red).

Question 5

What is the purpose of performing a reticulocyte count in hematology?

Accepted Answer

To evaluate the bone marrow's erythropoietic activity and response to anemia

Answer

The reticulocyte count assesses bone marrow erythropoietic activity. Elevated reticulocytes indicate increased RBC production (response to hemolysis or blood loss); low counts suggest bone marrow suppression.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO Core Laboratory Procedures Questions and Answers 2