Fecal Blood Test

Fecal Blood Test

Why is this test done?	This test is done to help diagnose various digestive tract disorders. It is used to detect blood in the stools that is invisible to the eye.
How to prepare:	Do not eat red meat, beets, turnip, horseradish or foods made of blood in the three days prior to the test. Stop taking iron supplements, non steroidal anti-inflammatory drugs (Advil™, etc.), colchicine, salicylates, prednisone, dexamethasone, acetylsalicylic acid and vitamin C three to five days before the test. If a drug cannot be stopped prior to the test for medical reasons, you should mention it to the person who will draw your blood. Do not drink alcohol in the three days prior to the test.
Target Values:	Negative test
Associated Tests:	If the test is positive, other exams will be done to identify the source of the blood.

General Information

A very small amount of blood can be found in normal stools. This blood is invisible to the eye. When the digestive tract's mucosa is damaged, the stools will contain larger than normal amounts of blood.

What does a positive result mean?

Blood in the stools can be caused by several digestive tract disorders, such as polyps, ulcers, varicose veins, intestinal inflammatory diseases, recent trauma or surgery, haemorrhoids and certain cancers.

Factors that can affect the result of the test

Several factors can influence the result of this test and cause a false-positive result, for example eating foods made with blood or red meat in the three days before the test. Recent dental surgery, taking the sample during menses, hemorrhoid, bleeding of the gums or extreme physical activity may also cause false-positive results. Certain drugs can also be blamed, they include:

• acetylsalicylic acid (Aspirin™)
• colchicine
• dexamethasone (Decadron™)
• indomethacine (Indocid™)
• phenylbutazone (Tandearil ™)
• prednisone (Deltasone™)
• iron supplements (Palafer ™)

Vitamin C can also cause a false-positive result because the test detects it as blood. Bleeding haemorrhoids can also cause a false-positive result.

What you need to know before the test

Before going for blood tests, a procedure or other exam, it is best to always bring a list of all the drugs you take (prescription, OTC and natural health products). Unless told otherwise, you should take your medication as usual on the day of the test. When in doubt, ask your pharmacist for more information.