How do I Collect a Fecal Occult Blood (FOB) Specimen?


The FOB test detects small amounts of blood in your feces (sometimes called stools or motions), which you would not normally see or be aware of.

How is the test done?

Usually 3 FOB tests are done on three separate samples of faeces, obtained on different days. This is because a bleeding disorder of the intestine may only bleed now and then. So, not every sample may contain blood. A series of 3 samples done on several days may be more accurate in detecting a bleeding intestine disorder.

There are some foods and medications which may affect the results of some FOB tests, making it false-positive or false-negative. Your doctor may ask you to avoid certain foods or medicines for about three days before the test. For about three days before the test, your doctor may ask you to avoid:

  • Certain fruits and vegetables, including broccoli and turnips
  • Red meat
  • Horseradish
  • Vitamin C supplements
  • Pain relievers, such as aspirin and ibuprofen (Advil, Motrin IB, others)

You will be provided a paper container to collect a sample of stool. It is for you to put on flushing system, making it easier to collect the sample. Please do not include urine with the stool collection.

You then use the spoon of the bottle to collect a sample of stool from the paper container; the amount should be enough to cover the bottom of the sample bottle.

Discard the paper container and return the stool sample bottle to the clinic during working hours (Mondays to Sundays 9 am – 5pm) or to the Laboratory directly during after working hours.

Please send the sample by sequence (No. 1, No. 2 and No. 3).


Your doctor will review the 3 results of the fecal occult blood test and then share the results with you. For accurate results, please follow the instructions and return the samples promptly.