ASCP Urinalysis and Body Fluids 3

Question 1

Bence Jones proteins detected in urine are composed of:

Accepted Answer

Free monoclonal light chains (kappa or lambda)

Answer

Bence Jones proteins are free monoclonal immunoglobulin light chains excreted in urine, characteristic of multiple myeloma.

Question 2

Which urine finding indicates renal tubular damage in acute tubular necrosis?

Accepted Answer

Muddy brown granular and epithelial cell casts

Answer

Muddy brown granular casts and renal tubular epithelial (RTE) cell casts are pathognomonic for acute tubular necrosis.

Question 3

Normal CSF total protein concentration is approximately:

Accepted Answer

15–45 mg/dL

Answer

Normal CSF protein is 15–45 mg/dL in lumbar specimens; elevated protein (>45 mg/dL) suggests inflammation, infection, or blood-brain barrier disruption.

Question 4

Which urine dipstick reaction can be falsely negative in the presence of high-dose ascorbic acid?

Accepted Answer

Glucose (oxidase method)

Answer

Ascorbic acid is a reducing agent that interferes with the glucose oxidase reaction, causing false-negative glucose results on dipstick.

Question 5

A synovial fluid WBC of 50,000–200,000/µL with >90% PMNs is most consistent with:

Accepted Answer

Septic arthritis

Answer

Septic arthritis typically shows WBC >50,000/µL with >90% neutrophils; crystals and lower counts are seen in gout and inflammatory arthritis.

ASCP Practice Test

ASCP Practice Test

ASCP Urinalysis and Body Fluids 3