MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 46
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
The most common cause of serious infections in chronic lymphocytic leukemia is:
CLL cells do not make normal antibodies, and normal B-cell function is suppressed. The resulting low immunoglobulin levels lead to recurrent bacterial infections.
Plasma fibrinogen often rises in infection and inflammation because fibrinogen is:
Fibrinogen is an acute-phase protein made by the liver, so it rises with inflammation. This also helps explain the raised ESR in inflammation.
In hemolytic anemia, urine urobilinogen is typically:
More bilirubin reaches the gut and is converted to urobilinogen, so more is reabsorbed and excreted in urine. Urine bilirubin stays negative because unconjugated bilirubin is not filtered.
Hereditary spherocytosis is most often inherited as which pattern?
About three-quarters of HS cases are autosomal dominant, which is why a parent is often affected. The rest are recessive or new mutations.
A thick malaria film is not fixed with methanol before staining because:
Leaving the thick film unfixed lets the water-based stain lyse (dehemoglobinize) the red cells, so parasites in the thick layer can be seen. The thin film is fixed to keep red cells intact.
Under Westgard rules, a single control result beyond ±3 SD from the mean (a 1-3s violation) means:
A 1-3s violation is a rejection rule. Patient results from that run should not be reported until the error is found and corrected. The 1-2s rule is only a warning.
Forward and reverse ABO typing results do not agree. What is the first step?
Many discrepancies come from clerical or technical errors, so the tests are repeated first (with a new sample if a wrong-blood sample is suspected). The ABO group must not be reported until the discrepancy is resolved.
Naturally occurring anti-A and anti-B are thought to be stimulated by:
Gut bacteria and foods carry carbohydrates similar to A and B, which stimulate antibody against whichever antigen the person lacks, without any red cell exposure.
In Fisher-Race notation, the letter 'd' means:
'd' only shows that D is absent. No d antigen or anti-d has ever been found.
Rh antigens are encoded by which genes?
RHD codes for the D protein and RHCE codes for the C/c and E/e antigens. Both are on chromosome 1. The three-gene idea of Fisher-Race is historical.
22% bovine albumin enhances agglutination in antibody tests mainly by:
Albumin lowers the zeta potential (the repulsive charge between red cells), so IgG-coated cells can come close enough to agglutinate.
A group AB patient needs plasma. Which plasma group is ABO-compatible?
Group AB red cells carry both A and B antigens, so plasma must contain neither anti-A nor anti-B. Only group AB plasma meets this.
The name on a pretransfusion sample tube does not match the name on the request form. What is the correct action?
Mislabeled or mismatched samples must be rejected because they may come from the wrong patient. Labels must never be corrected in the laboratory.
Uncrossmatched red cells were issued in an emergency. What should the laboratory do afterwards?
Emergency release does not remove the need for testing. Standard tests are completed as soon as possible, and any incompatibility is reported urgently so the patient can be watched or treated.
One apheresis platelet unit contains roughly the same number of platelets as how many whole-blood-derived platelet units?
An apheresis unit contains at least 3 × 10^11 platelets, about the same as 4–6 pooled whole-blood-derived units, and it comes from a single donor.
Mannitol is added to SAGM additive solution mainly to:
SAGM contains saline, adenine, glucose and mannitol. Mannitol protects the membrane and reduces hemolysis during storage.
Transfusion-transmitted syphilis is rare mainly because Treponema pallidum:
T. pallidum does not survive long at refrigerator temperature, and donors are also screened serologically.
A donated unit is repeatedly reactive in the anti-HCV screening test. What happens to the unit?
Units that are repeatedly reactive for a mandatory infectious marker must not be transfused. The donor is deferred and counseled according to confirmatory results.
Mild allergic (urticarial) transfusion reactions are mainly caused by:
Soluble substances in donor plasma bind recipient IgE on mast cells and basophils, releasing histamine and causing hives and itching.
An adult has a fasting plasma glucose of 140 mg/dL (7.8 mmol/L) on two separate days. By ADA criteria this indicates:
A fasting plasma glucose of 126 mg/dL (7.0 mmol/L) or higher, confirmed on repeat testing, meets ADA criteria for diabetes. Impaired fasting glucose is 100–125 mg/dL (5.6–6.9 mmol/L).