MLT GlobeMOH exam preparation (UAE) – page 17
700 practice MCQs for the MOH medical laboratory exam. Level: Basic to intermediate.
A refrigerated alkaline urine has a heavy white precipitate. Microscopy shows granular amorphous material. This precipitate will dissolve after adding:
White amorphous phosphates form in alkaline urine and dissolve in dilute acid. Warming dissolves amorphous urates (pink, acidic urine), not phosphates.
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.
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.
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.
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.
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.
Until all donor screening tests are completed and negative, collected units are kept:
Untested units are quarantined so they cannot be issued by mistake. They are released only after all mandatory tests are negative and labeling is complete.
Acute transfusion reactions are those that occur within:
Reactions within 24 hours are called acute. Those appearing later (such as delayed hemolysis or TA-GVHD) are called delayed.
Febrile non-hemolytic transfusion reactions are best reduced by using:
Most febrile reactions are caused by donor white cells or the cytokines they release during storage. Leukoreduction before storage greatly reduces them, while irradiation does not.
Which is an infectious complication of transfusion?
Hepatitis C is a transfusion-transmitted infection, which donor screening aims to prevent. The other options are non-infectious reactions.
How should urine reagent strips be stored?
Moisture, light, heat and volatile chemicals damage the reagent pads. Strips are kept in their capped container with desiccant and are not refrigerated or frozen.
Transitional (urothelial) epithelial cells in urine come from which part of the urinary tract?
Urothelium lines the renal pelvis, ureters, bladder and upper urethra. Renal tubular cells come from the tubules and squamous cells from the vagina and distal urethra.
An abnormal accumulation of fluid in the peritoneal cavity is called:
Ascites is excess peritoneal fluid; it is collected by paracentesis. Pleural and pericardial effusions are fluid around the lungs and heart.
Most of the volume of semen is contributed by the:
The seminal vesicles provide about 60–70% of the ejaculate volume, including fructose. The prostate adds about 20–30%; sperm from the testes form only a small part.
Amphotericin B and the azole antifungals act on which component that is found in fungal cell membranes but not in human ones?
Ergosterol is the main fungal membrane sterol; amphotericin binds it and azoles block its synthesis.
A 'fungus ball' growing inside an old tuberculous lung cavity is usually caused by:
Aspergillus fumigatus commonly colonises existing lung cavities, forming an aspergilloma.
Tinea pedis is commonly known as:
Tinea pedis is dermatophyte infection of the feet; jock itch is tinea cruris and Madura foot is mycetoma.
Dermatophytes infect which tissues?
Dermatophytes use keratin, so they infect only the outer skin, hair and nails.