Core Laboratory Procedures Questions and Answers Flashcards
6 cards from real MLPAO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Core Laboratory Procedures Questions and Answers flashcards as text
What is the purpose of centrifugation in specimen processing in a medical laboratory?
Answer: To separate blood into its cellular and liquid components
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.
What does the term 'hemolysis' mean in the context of laboratory specimen quality?
Answer: Rupture of red blood cells releasing hemoglobin into the plasma/serum
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.
In clinical chemistry, what is a 'blank' in the context of spectrophotometric analysis?
Answer: A solution containing all reagents but no analyte, used to zero the instrument
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.
What is the principle of the Gram stain in clinical microbiology?
Answer: Differentiates bacteria based on cell wall composition into Gram-positive (purple) and Gram-negative (pink) groups
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).
What is the purpose of performing a reticulocyte count in hematology?
Answer: To evaluate the bone marrow's erythropoietic activity and response to anemia
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.
In urinalysis, what does a positive nitrite result on a urine dipstick indicate?
Answer: Presence of Gram-negative bacteria that convert dietary nitrates to nitrites
A positive nitrite on urine dipstick indicates the presence of bacteria (typically Gram-negative) that contain nitrate reductase enzymes, which convert dietary nitrates to nitrites in the bladder urine.