Which urine specimen type requires discarding the first void?

The requirement to discard the first void is specifically associated with midstream clean catch urine specimens. In this collection method, the first portion of urine is discarded to reduce the likelihood of contamination from the urethra or external genitalia. This is critical for obtaining a specimen that more accurately reflects the condition being tested, particularly for detecting infections or other abnormalities in the urine.

While the other specimen types have their own collection protocols, the first morning urine specimen is typically collected without discarding any volume, as it is used for specific tests like pregnancy testing or hormone level assessment. Pediatric urine collections often utilize methods suited to the age and capability of the child rather than follow a strict discard protocol. A 24-hour urine collection involves collecting urine over an entire day, with no requirement to discard the first void since the entire urine output is needed for analysis.

The midstream clean catch methodology is therefore the only collection method of the options given that necessitates discarding the first void to ensure a clean and uncontaminated specimen.