Which of the following urine specimens should a medical assistant collect from a patient for the diagnosis of a urinary tract infection?

A second-voided specimen is collected after the first urination, which may still be contaminated with bacteria from the urethra. This method does not provide a reliable sample for UTI diagnosis, as it can include residual contaminants that compromise the accuracy of the test results.

A 2-hour postprandial urine specimen is collected after eating, primarily to measure glucose levels or assess kidney function related to dietary intake. This type of collection is not suitable for diagnosing UTIs, as it is focused on metabolic responses rather than providing an uncontaminated urine sample.

A 24-hour urine collection gathers all urine produced in a complete day, typically used to assess kidney function or measure substances like protein or creatinine levels. While it provides comprehensive data, it is not practical for UTI diagnosis since it does not focus on the specific characteristics of a single, clean sample needed to identify infection.