A clean catch urine sample is collected midstream, after you’ve cleaned the area around your urethra, so the sample reflects what’s actually in your bladder rather than bacteria living on your skin. The technique takes about two minutes and is the same whether you’re doing it at a clinic or at home with a kit. Here’s exactly how to do it.
Why the First Part of the Stream Is Discarded
When you start urinating, the initial flow picks up bacteria and skin cells from the lower urinary tract. The middle portion of the stream is usually clear of these contaminants, which makes it far more reliable for detecting a true urinary tract infection or other conditions. Skipping the cleaning step or catching the first splash of urine can introduce enough skin bacteria to trigger a false positive result, potentially leading to unnecessary treatment or a repeat test.
Instructions for Women
You’ll typically receive a kit with sterile wipes and a collection cup. Sit on the toilet with your legs apart and use two fingers to spread your labia open. With the first wipe, clean the inner folds of the labia from front to back. Use a second wipe to clean over the urethral opening, which sits just above the vaginal opening. Always wipe front to back to avoid dragging bacteria toward the urethra.
Keeping your labia spread apart, begin urinating into the toilet. After a second or two, stop the flow. Then hold the collection cup a few inches from your urethra and urinate until the cup is roughly half full. You can finish urinating into the toilet. Try not to touch the inside of the cup or let it contact your skin, since that reintroduces the bacteria you just cleaned away.
Instructions for Men
If you’re uncircumcised, pull back your foreskin with your non-dominant hand before cleaning. Use the provided antiseptic wipe to clean the entire head of the penis, paying particular attention to the area around the urethral opening at the tip. If your kit includes multiple wipes, use each one separately rather than reusing the same wipe.
Start urinating into the toilet. Without stopping your stream, move the collection cup into position and fill it to about the halfway mark. Then finish urinating into the toilet. Keep your foreskin retracted (if applicable) during the entire process so the cleaned area stays exposed.
Collecting From Infants and Toddlers
Babies who aren’t toilet trained can’t provide a midstream sample on their own, so clinics use a small plastic bag with an adhesive strip designed to fit over the genital area. Start by thoroughly washing the skin around the urethra with the soap or wipes your provider recommends. For girls, clean from front to back. For boys, clean from the tip of the penis downward.
Peel the backing off the adhesive strip and press the bag into place. For boys, the entire penis goes inside the bag. For girls, position the bag over the labia. Then put a diaper over the bag to hold it in place. Check frequently. Once your baby has urinated, remove the bag promptly and transfer the sample into the collection container.
How to Handle the Sample Afterward
Timing matters once the cup is filled. Urine left at room temperature stays reliable for up to about four hours, with one study showing 97 to 100 percent agreement between results tested at two hours and four hours. Beyond that window, bacteria in the sample can multiply and skew results. If you can’t get the sample to a lab within a couple of hours, place it in the refrigerator (around 4°C or 39°F) until you’re ready to transport it. Most labs will give you a small bag or container for this purpose.
When you hand off the sample, make sure the lid is screwed on tightly and your name and the collection time are on the label. Some clinics ask you to initial the cup to confirm identity.
Common Mistakes That Ruin a Sample
The most frequent problem is contamination from skin cells. When labs examine urine under a microscope, they look for flat skin cells called squamous epithelial cells as a marker of a poorly collected sample. High counts of these cells reduce the accuracy of the urinalysis and can make it harder for the lab to determine whether bacteria in the sample represent a real infection or just surface contamination.
Other pitfalls to avoid:
- Catching the first part of the stream. This defeats the purpose of a clean catch. Let the initial flow go into the toilet for at least one to two seconds before positioning the cup.
- Touching the inside of the cup or lid. Your fingers carry bacteria that will show up in the results.
- Letting the cup contact your skin. Hold it a few inches away from your body while collecting.
- Skipping the cleaning step. Even if you showered recently, the antiseptic wipe removes bacteria that normal bathing leaves behind.
- Overfilling the cup. Half full is the target. Overfilling makes it harder to seal without spilling and doesn’t improve the test.
If you suspect your sample was contaminated, or if the cup slipped and touched the toilet seat, it’s better to ask for a new cup and start over than to submit a questionable specimen and risk being called back for a retest.