MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 13
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
When old red cells are broken down in macrophages, the heme (after iron is removed) is converted to:
Heme oxygenase opens the heme ring to form biliverdin, which is reduced to unconjugated bilirubin. The iron is recycled.
Türk's solution for manual white cell counts lyses red cells because it contains:
Türk's fluid is dilute acetic acid, which lyses red cells, plus gentian violet, which stains white cell nuclei.
The hematocrit (packed cell volume) is:
The hematocrit is the fraction of blood volume occupied by red cells, reported as % or L/L. MCH is hemoglobin per cell and MCV is average cell volume.
A microscope with a 10× eyepiece and a 100× oil-immersion objective gives a total magnification of:
Total magnification is eyepiece × objective: 10 × 100 = 1000×.
Sahli's method estimates hemoglobin by converting it to:
Sahli's method mixes blood with 0.1 N HCl to form brown acid hematin, which is diluted with water until it matches a glass standard.
Daily quality control results for an analyzer are plotted over time on a:
A Levey-Jennings chart plots control values against the mean and SD limits over time, helping to spot shifts and trends. A Price-Jones curve shows red cell diameters.
A 5-part automated differential reports which cell types?
A 5-part differential sorts white cells into the five normal types. Abnormal cells such as blasts are only flagged and must be checked on a smear.
Who discovered the ABO blood group system?
Karl Landsteiner described the ABO groups in 1900–1901 and later received the Nobel Prize. Coombs developed the antiglobulin test.
Red cells react with both anti-A and anti-B, and the plasma reacts with neither A1 nor B reagent cells. The ABO group is:
Both antigens on the cells and no anti-A or anti-B in plasma is the pattern of group AB, and forward and reverse results agree.
Reverse (serum) grouping is important in ABO typing mainly because it:
Forward and reverse grouping must agree. The reverse group confirms the forward result and helps to reveal errors and discrepancies.
The Rh blood group system was named after:
The name comes from rhesus monkeys. Antibodies raised against their red cells by Landsteiner and Wiener reacted with most human red cells.
In Wiener notation, R2 corresponds to which Fisher-Race haplotype?
R2 = DcE. R1 = DCe, R0 = Dce and r = dce.
Anti-D in a D-negative person usually arises after:
Anti-D is an immune antibody formed only after exposure to D-positive red cells, unlike naturally occurring anti-A and anti-B.
Anti-K is most often of which immunoglobulin class?
Anti-K is usually an IgG immune antibody detected at the AHG phase. It can cause hemolytic transfusion reactions and HDFN.
The antigens Jka and Jkb belong to which blood group system?
Jka and Jkb are the Kidd antigens. Kidd antibodies are known for causing delayed hemolytic transfusion reactions.
Most blood group alleles, such as Jka and Jkb or Fya and Fyb, are expressed:
Blood group alleles are codominant. A Jk(a+b+) person has inherited both alleles and expresses both antigens.
Before a pretransfusion blood sample is collected, the patient must be identified using at least:
Positive patient identification with at least two identifiers prevents wrong-blood-in-tube errors. Bed numbers are never acceptable identifiers.
Fresh frozen plasma is used because it contains:
Freezing plasma soon after collection keeps all clotting factors, including the unstable factors V and VIII.
Where should red cell units be stored before transfusion?
Red cells need a dedicated blood bank refrigerator with continuous temperature monitoring and alarms. Domestic refrigerators are not controlled, and freezing without glycerol lyses red cells.
The 'window period' of an infection in blood donors is the time when:
Early after infection, the agent may be in the blood before antibodies or antigens reach detectable levels. NAT shortens this window but does not remove it.