What is the most appropriate time to collect urine for pregnancy testing?

The first urine of the day is the most appropriate sample to collect for pregnancy testing because it is typically the most concentrated. This concentration increases the likelihood of detecting the hormone human chorionic gonadotropin (hCG), which is produced shortly after a fertilized egg attaches to the uterine lining. During the morning, the urine has been held in the bladder overnight, resulting in a higher concentration of hCG if pregnancy is present.

Using a random urine sample may not guarantee the same level of concentration, as urinary dilution can vary throughout the day depending on fluid intake and other factors. Collecting urine after drinking a large amount of water would dilute the sample, potentially making it more difficult to confirm the presence of hCG. Taking a sample before meals is not as relevant to pregnancy testing, as its effectiveness is not influenced by the timing with respect to meals. Thus, for optimal accuracy in test results, the first urine of the day is the best choice.