Canadian Society for Medical Laboratory Science (CSMLS) Practice Exam

Which endocrine test is not performed on a 24-hour urine?

1. VMA

2. TSH

3. BJ Protein

4. 17 KS

The correct answer is: BJ Protein

The correct answer revolves around the nature of the tests and the typical specimen types used for their measurement. The BJ Protein test, which refers to Bence Jones protein, is primarily assessed through serum and urinary specimens but does not specifically require a 24-hour urine collection for diagnosis or monitoring. In contrast, tests like VMA (vanillylmandelic acid), 17 KS (17-ketosteroids), and TSH (thyroid-stimulating hormone) often use 24-hour urine collections or serum specimens. VMA and 17 KS are hormones related to catecholamine metabolism and steroid evaluation, respectively, and can provide a more accurate assessment with a 24-hour urine sample to account for variations in hormone excretion throughout the day. TSH is usually measured in serum, but its mention here may lead to confusion, as it doesn't fit within the context of 24-hour urine tests. However, the specific characteristic of the BJ Protein test being unnecessary in a 24-hour urine collection clearly sets it apart, affirming that it is not performed in that context.