A patient’s urine shows a 'small' blood result on the reagent strip. In which of the following scenarios could this occur in a healthy person?

• A. Crash dieting for a weekend event
• B. Going from laying down to standing/ walking
• C. Menstruation
• D. Hemorrhoid

Answer: (C)

A small appearance of blood on a urine dipstick in a healthy person is most commonly due to vaginal contamination during menstruation. The dipstick detects heme, so even a tiny amount of blood from menstrual fluid contaminating the sample can produce a faint positive. In contrast, crash dieting, orthostatic changes, or hemorrhoids don’t introduce blood into the urine in a healthy person, and a true renal bleed would more likely show a persistent or microscopic red cell presence rather than a one-time, contamination-related result. If menstruation is suspected, repeating the test with a clean-catch sample away from menses helps confirm whether the dipstick result was due to contamination.