CLT CLT Microbiology & Urinalysis 2

Question 1

Waxy casts found in urine sediment are associated with which clinical condition?

Accepted Answer

Severe chronic renal failure

Answer

Waxy casts form from the degeneration of granular casts in nephrons with very slow urine flow and indicate severe chronic renal disease.

Question 2

A urine dipstick is positive for nitrites. What does this finding indicate?

Accepted Answer

The presence of nitrite-reducing bacteria (gram-negative organisms)

Answer

Many gram-negative bacteria reduce dietary nitrates to nitrites; a positive nitrite result on dipstick suggests a bacterial UTI caused by gram-negative organisms.

Question 3

Which agar is used for the isolation of Neisseria gonorrhoeae and other fastidious organisms?

Accepted Answer

Thayer-Martin agar

Answer

Thayer-Martin agar is an enriched selective medium containing antibiotics (VCN — vancomycin, colistin, nystatin) that inhibit normal flora while supporting growth of Neisseria species.

Question 4

In urine microscopy, which finding is most associated with acute glomerulonephritis?

Accepted Answer

RBC casts

Answer

RBC casts indicate that red blood cells have leaked through damaged glomeruli and formed casts in the tubules, which is pathognomonic for glomerulonephritis.

Question 5

The coagulase test is used to differentiate which two clinically important Staphylococcus species?

Accepted Answer

S. aureus (positive) from S. epidermidis (negative)

Answer

Coagulase production distinguishes the pathogenic S. aureus (coagulase-positive) from coagulase-negative staphylococci such as S. epidermidis.

(CLT) Clinical Laboratory Technologist Certification Practice Test

(CLT) Clinical Laboratory Technologist Certification Practice Test

CLT CLT Microbiology & Urinalysis 2