Which statement about first morning urine for pregnancy testing is true?

• A. It is less likely to be contaminated
• B. It is typically more concentrated
• C. It has a higher pH
• D. It is never preferred

Answer: (B)

First morning urine is preferred because it is more concentrated after a night of urine production. The pregnancy test detects the hormone hCG in urine, and a higher concentration of urine means a higher concentration of hCG, making it more likely to reach the test’s detection threshold early in pregnancy. The pH of morning urine isn’t the deciding factor—immunoassays for hCG are designed to work across the range of normal urine pH, so the reason morning samples are favored is mainly the increased hCG concentration. While some tests can use any urine sample, the morning specimen offers the best chance of accurate detection, especially early on. Contamination risks can occur with any sample and aren’t the primary advantage of the morning collection.