What to do with your FOB test kit

A FOB (faecal occult blood) test checks your bowel motions for tiny amounts of ‘hidden blood’. Blood in your bowel motions can be caused by bowel cancers and polyps. This is not a test for cancer. It is used to find people who may be at risk of developing bowel cancer.

The FOB test is used as part of bowel screening programmes. You will receive your FOB test kit by post. You need to collect two samples, from three different bowel motions. Each sample should be put onto the test card included in the pack. The card has three flaps, one for each bowel motion. Under each flap there are two windows. After collecting a sample of bowel motion, spread it thinly over each window and seal the flap.

You need to collect the bowel motion, without it touching the toilet bowl. Try collecting it in a clean, disposable plastic container or on some folded tissue.

Seal the completed test card in the prepaid hygienic envelope and send it in the post to be tested. Your FOB test results will arrive by letter.

About the test

Bowel cancers and polyps can sometimes bleed, which is why screening looks for blood in your bowel. Occult blood means blood that is not visible to the eye and the faecal occult blood (FOB) test is a way of detecting tiny amounts of 'hidden' blood in your bowel motions.

The test doesn't tell you if you have bowel cancer, or a polyp, but if you have blood in your bowel motions you may be offered further tests, such as a colonoscopy, to find out the cause of the bleeding.

If you are sent an FOB test kit and you aren't sure whether you should do the test or not, you should call the freephone helpline number, which is on the letter that comes with the test.

You don't have to take part in the bowel cancer screening programme. If you don't want to take part you can simply choose not to complete and return the FOB test kit, or you can contact the freephone number on the letter to let the programme know that you don't want to participate.

The FOB test kit

After you've received a letter inviting you to take part in the bowel cancer screening programme, you'll be sent an FOB test kit and instructions, which you use in the privacy of your own home. In Scotland you'll be sent the letter at the same time as the kit.

The kit includes:

  • full instructions
  • six cardboard sticks to collect the samples
  • an orange or red and white test card
  • a prepaid hygienic envelope to return the samples.

There are three parts to the test for three separate bowel motions.

FOB test kit
FOB test kit

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Doing the test

Before collecting each bowel motion it's a good idea to get everything ready. You'll need to have:

  • two of the cardboard sticks
  • the orange or red and white test card.

Write the date on the first flap on the test card, then peel back the flap. Underneath you'll see two windows – one for each sample of your bowel motion.

FOB test kit instructions
FOB test kit instructions

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Collecting your samples

It's important that the bowel motion you use to collect your sample from has not been in the toilet bowl, as this can affect the result of the test. You can collect the bowel motion in different ways. You can use a clean disposable plastic container, such as a cleaned ice cream tub, or folded toilet paper. Alternatively you can collect it on a sheet of newspaper, which you can place across the toilet pan and secure under the rim of the toilet seat. Make sure the newspaper doesn't touch the water in the toilet.

Once you've collected your bowel motion, use one of the cardboard sticks to take a small piece. Spread it thinly over the first window on the test card. Use the second cardboard stick to collect a sample from a different area of your bowel motion. Spread it thinly over the second window.

Once you've completed both windows, seal the flap on the test card. Wipe the cardboard sticks with toilet paper, wrap them up and throw them away in an outside bin. Don't flush them down the toilet.

The second and third samples are collected in the same way, using the two windows on the test card under flap two and then flap three. All three samples need to be taken from three different bowel motions, but they don't have to be collected from three in a row. It's important that all the samples are collected and the kit returned within 14 days of the first sample. Once you have all three samples, you can send the kit to be tested using the prepaid hygienic envelope.

It's very important that you follow the instructions carefully – particularly paying attention to the diet and drug advice given in the kit.

If you have any questions about the sample collection, or if you need a new test kit to start again, you can call the freephone helpline number, which is printed on the kit instructions.

If you don't return the test kit, you'll get a reminder after about four weeks. If you've decided not to participate in the screening programme, you can either ignore the reminder or contact the helpline number to tell them you won't be sending your kit back.

Back to Bowel screening

The bowel

The bowel is part of our digestive system and is made up of the small bowel and the large bowel.


A colonoscopy is a way of examining the lining of the bowel from the inside.

CT colonography

This test uses a CT scanner to create a picture of the bowel.