MLT GlobeHematology: Hematology methods & instruments – page 5
83 Hematology MCQs on Hematology methods & instruments with answers and explanations.
In impedance counters, a 'sweep flow' behind the red cell aperture is used to prevent:
Answer: B. Cells swirling back into the sensing zone and being counted again as platelets
Cells that have passed the aperture can recirculate near it and create small extra pulses that mimic platelets. A steady sweep flow carries them away; coincidence is corrected mathematically, not by sweep flow.
ID MG-HEM-0324 · Found a mistake? Report it
Bull's moving average algorithm monitors hematology analyzer performance by tracking which parameters in batches of patient samples?
Answer: B. MCV, MCH and MCHC
Red cell indices are very stable across a patient population, so a shift in their moving average suggests an analyzer problem. WBC and platelet counts vary too much between patients for this use.
ID MG-HEM-0329 · Found a mistake? Report it
ICSH recommends K2EDTA rather than liquid K3EDTA for blood counts mainly because K3EDTA:
Answer: D. Dilutes the sample and shrinks red cells, lowering MCV
Liquid K3EDTA dilutes the blood by about 1–2% and causes more red cell shrinkage, lowering MCV and Hct. Spray-dried K2EDTA avoids dilution.
ID MG-HEM-0336 · Found a mistake? Report it
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