Can You Do a FIT Stool Test During Your Period?

Wait until your period has finished before collecting a FIT stool sample. For England’s bowel screening programme, the advice goes further: avoid collection during bleeding and in the two days before and after it. FIT checks a small stool sample for blood. These collection instructions apply in England; check the leaflet supplied with your own kit if you use another service.¹

Does a GP-requested FIT use the same timing?

Check who sent the kit. A routine screening invitation and a test ordered because of symptoms have different follow-up arrangements.

The NHS England London² leaflet for a GP-requested FIT says to collect after menstruation finishes and complete the test as soon as possible. It does not give the screening leaflet’s additional two-day interval. It directs patients to return the sample to their GP practice, rather than posting it to the screening programme.²

Follow your service’s collection and return directions. If they are missing, ask the practice for a replacement before sampling. Mention that you are bleeding and ask when they want the sample. Do not assume a return envelope from a previous screening invitation belongs to a newly ordered test.

What if bleeding is irregular or the sample is already collected?

If you cannot predict your next period, or bleeding keeps postponing collection, contact the screening service or ordering practice for a plan. England’s screening helpline is 0800 707 60 60. Its leaflet provides that number for questions about using the kit.¹

If you collected during bleeding, tell the team when you collected it and whether you have already sent it. Ask whether a replacement is needed. Do not try to correct a sealed sample by reopening it: England’s kit instructions explicitly say to leave it closed after use.³

How much stool goes on the stick?

For England’s screening kit, catch the stool in a container or on layers of toilet paper, keeping it out of toilet water. Scrape the collection stick over the surface until its grooves are covered. A small amount is sufficient; adding extra is not part of the instructions.³

Write the collection date on the bottle, return the stick and close the cap until it clicks. Wash your hands. Put the bottle into the supplied return envelope, seal it and post it promptly. Check the directions accompanying your kit before using these steps for another test.³

Should symptoms wait until I can collect?

Contact a GP about bowel symptoms even if you cannot collect the sample yet. Examples include a new change in bowel habit, blood in stool, unexplained weight loss or persistent abdominal symptoms. Tell the clinician if you cannot tell whether blood came from the vagina or the bottom. The NHS⁴ advises assessment of bowel cancer symptoms; having them does not establish cancer.⁴

Black or dark-red stool, or bloody diarrhoea, needs an urgent GP appointment or NHS⁴ 111. Nonstop bleeding from the bottom, a large amount of blood or large clots needs 999 or A&E. Those instructions concern bleeding from the bowel, not an ordinary period.⁴

Bloated by Dinner includes “The Red-Flag List,” which explains why blood in stool and other warning signs need assessment. Its distinction between routine screening and a visit for symptoms is useful here: a collection delay should not become a delay in reporting a bowel change.