MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 18
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
Leprosy mainly damages the skin and which other tissue?
M. leprae prefers cooler tissues and invades Schwann cells, causing sensory loss and deformity.
Tuberculosis of the spine is known as:
Pott's disease is spinal TB; scrofula is TB of cervical lymph nodes and lupus vulgaris is skin TB.
Which drug is the usual treatment for Trichomonas vaginalis infection?
Metronidazole (or tinidazole) is the standard treatment, and sexual partners are treated at the same time.
Giardia duodenalis trophozoites attach to the small-intestinal mucosa by means of a:
The concave ventral disc on the underside of the trophozoite acts like a suction cup on the duodenal epithelium.
Heavy Trichuris trichiura infection in young children can cause:
Many whipworms embedded in the colonic and rectal mucosa cause dysentery-like illness and rectal prolapse in heavily infected children.
Humans acquire the Chinese liver fluke Clonorchis sinensis by eating:
Metacercariae encysted in freshwater fish are eaten raw; watercress transmits Fasciola.
Lung fluke (Paragonimus) infection is acquired by eating raw or undercooked:
Metacercariae of Paragonimus develop in freshwater crustaceans eaten raw, pickled or undercooked.
A thick blood film for malaria is not fixed with methanol before Giemsa staining because:
Unfixed red cells lyse (dehaemoglobinise) in the aqueous stain, leaving parasites and white cells visible.
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.
Fungal infection of the nails is called:
Onychomycosis is nail infection, most often by dermatophytes; otomycosis affects the ear canal.
Aflatoxin, a toxin in poorly stored grains and nuts that can cause liver cancer, is produced by:
A. flavus grows on stored crops and produces aflatoxin, a potent liver carcinogen.
The Sabin oral polio vaccine (OPV) contains:
OPV is a live attenuated oral vaccine; the Salk vaccine (IPV) is inactivated and injected.
A Class II biological safety cabinet protects:
HEPA-filtered downflow and exhaust air in a Class II cabinet protect the sample, the operator and the room.
In a normal (Gaussian) distribution of control results, about what percentage of values lie within ±2 SD of the mean?
About 68% of values lie within ±1 SD, 95% within ±2 SD and 99.7% within ±3 SD.
Specificity of a diagnostic test is the proportion of:
Specificity = true negatives ÷ (true negatives + false positives); the proportion of diseased people testing positive is sensitivity.
Blood collected in a plain or gel serum tube should be allowed to clot before centrifugation for about:
About 30 minutes at room temperature allows complete clotting; centrifuging too early leaves fibrin in the serum.
5 g of a solute is dissolved in water to a final volume of 250 mL. What is the percent (w/v) concentration?
Percent w/v is grams per 100 mL: 5 g ÷ 250 mL × 100 = 2%.
A pH meter is calibrated before use with:
Buffers of known pH, such as 7.0 and 4.0 or 10.0, are used to calibrate the electrode across the working range.
Which part of a light microscope focuses light onto the specimen?
The condenser below the stage gathers and focuses light on the specimen; its iris diaphragm controls the amount of light.