How to Check for Pinworms: Nighttime Look and Morning Tape Test

Pinworms are easier to find when you check at the right time. The two most useful approaches are looking for adult worms after sleep begins and collecting eggs with clear tape first thing in the morning.

Method 1: Look at night

Check the skin around the anus about two to three hours after the person falls asleep. Use a flashlight and look for very small, white, threadlike worms moving on the skin. They may also appear on underwear, pajamas or bedding. If nothing is seen, checking on two or three different nights can be more informative than checking once.

Method 2: The clear-tape test

1. Ask a healthcare professional how they want the sample collected and stored.
2. Immediately after waking—before bathing, using the toilet or getting dressed—press the sticky side of clear cellophane tape against the skin around the anus.
3. Place the tape sticky-side down on the slide or in the container supplied by the clinician.
4. Wash hands thoroughly.
5. Repeat on three consecutive mornings unless the clinician gives different instructions.

Why three mornings?

Eggs may not be deposited every night, so one negative sample does not always rule out infection. Repeating the collection improves the chance of capturing eggs for microscopic identification.

Why a stool test may be negative

Pinworm eggs are typically laid on the skin outside the anus, not released consistently into stool. That is why the tape test is generally more useful for pinworm than a routine stool parasite test.

Keep the process calm

Explain to a child that you are checking the skin for a common cause of itching. Avoid language that creates shame. Pinworms are common and can affect any household.