Stool Guaiac Test

How is the Test Performed?

A stool sample from three consecutive bowel movements is collected, smeared on a card, and mailed to a laboratory for processing. In order to ensure the accuracy of the guaiac test, it is important to follow, whenever available, the manufacturer's instruction on how to collect the stool.

Adults and children:
There are many ways to collect the samples. You can catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. Then put the sample in a clean container. One test kit supplies a special toilet tissue that you use to collect the sample, then put the sample in a clean container. Do not sample stool specimen from within the toilet bowl water, as this can cause measurement errors.

Infants and young children:
For children wearing diapers, you can line the diaper with plastic wrap. If the plastic wrap is positioned so that it isolates the stool from any urine output, mixing of urine and stool can be prevented for a better sample.

Laboratory procedures may vary. In one type of test, a small sample of stool is placed on a paper card. A drop or two of testing solution is applied to the opposite side of the card. A color change indicates the presence of blood in the stool.