A urinary tract infection is a common bacterial condition that occurs when microorganisms, typically Escherichia coli (E. coli), enter and multiply in the urethra or bladder. Symptoms often include a burning sensation during urination, increased frequency, and an urgent need to urinate. If you suspect you have an infection while menstruating, you can still get tested, as immediate diagnosis and treatment are important for preventing the infection from spreading. While menstrual fluid complicates the standard urine collection process, careful technique can yield a reliable sample for laboratory analysis.
Why Menstruation Can Affect Urine Testing
The primary concern with testing for a UTI during menstruation is the risk of sample contamination, which interferes with accurate lab results. Menstrual fluid contains components not normally found in urine but used as markers in a standard urinalysis test. These contaminants include red blood cells, white blood cells, protein, and epithelial cells.
When these elements enter the urine sample, they can lead to misleading or false positive results on a rapid dipstick test. For instance, the leukocyte esterase test, which detects white blood cells, may register positive due to white blood cells from menstrual blood rather than a urinary infection. Because a contaminated sample may suggest an infection or mask one that is present, specific steps are recommended to minimize this interference during collection.
Collecting an Accurate Sample During Your Period
Obtaining a clean-catch midstream urine sample is the most important step for a reliable UTI test while menstruating. This technique prevents menstrual fluid and external bacteria from mixing with the collected urine. Before collection, insert a fresh tampon, menstrual cup, or menstrual disc to divert the flow of blood away from the urinary opening.
Next, thoroughly cleanse the genital area using antiseptic wipes. Separate the skin folds around the urethra and wipe carefully from front to back, using a new wipe for each stroke. This cleansing action removes surface bacteria that could contaminate the sample and lead to inaccurate culture results.
To perform the midstream catch, begin urinating into the toilet for a few seconds to flush out organisms from the initial part of the urethra. Without stopping the stream, place the sterile collection cup into the path of the urine flow and fill it about halfway.
Remove the cup and finish voiding the rest of the urine into the toilet, ensuring you do not touch the inside of the cup or lid. Following these careful steps increases the chances of the lab receiving a sample that accurately reflects the presence of bacteria in the urinary tract.
Understanding Test Results and Next Steps
After collection, the sample is sent for analysis, typically involving both a urinalysis and a urine culture. Laboratory staff examine the sample for signs of contamination, often looking for high numbers of squamous epithelial cells or polymicrobial growth (multiple types of bacteria). If more than two different types of bacteria are found, or if the bacterial count is low, the sample is generally considered contaminated and the results unreliable.
To confirm a true infection, the lab relies on the urine culture, which identifies the specific type of bacteria and its concentration, measured in colony-forming units per milliliter (CFU/mL). A count of 100,000 CFU/mL or more of a single type of uropathogenic bacteria in a clean-catch sample is the classic threshold for diagnosing a UTI. However, lower counts (10,000 to 100,000 CFU/mL) may still indicate an infection if you are experiencing significant symptoms like burning pain or urgency.
The healthcare provider interprets the lab results alongside your clinical symptoms, as test findings alone are not always conclusive. If your sample shows heavy contamination but your symptoms are severe, the provider may begin immediate empirical treatment with antibiotics. If symptoms are mild or contamination is questionable, the provider may request a retest, sometimes using catheterization to obtain a sample entirely free of external contaminants.