Does Menstrual Cycle Affect Urinalysis?

Does Menstrual Cycle Affect Urinalysis? If you’re menstruating (on your period), it’s important to let your provider know before collecting your urine sample. Menstrual blood, as well as vaginal discharge, can interfere with certain urinalysis test results. How does being on your period affect urinalysis? Menstrual blood can contaminate a urine sample. Vitamin C supplements,