A fecal occult blood test (FOBT) is usually performed by the patient at home. A physician will give the patient a kit that explains the necessary steps. Kits can also be purchased at a pharmacy without a prescription. Cancers and other abnormalities bleed intermittently, so most patients are asked to take stool samples on three consecutive days.

There are many types of sample kits available. It is important that individuals carefully read the instructions enclosed with the kit to ensure accurate results. Most tests require the patient to obtain the sample and store it in a supplied container, or to use an applicator stick to apply the sample on a chemically treated card. These samples are then returned either in person or by mail in a special envelope to a laboratory or physician’s office. To ensure accuracy, these samples should be handled and stored as instructed until they are returned or mailed to the lab.

In some cases, the FOBT may be performed in a physician’s office. In these cases, the patient may provide a sample as part of a colorectal examination. More often, the test is completed through a home kit.

A fecal immunochemical test (FIT) is a newer type of stool blood test kit that detects a specific portion of a human blood protein. The test is performed in the same manner as an FOBT, but the fact that it is more specific reduces the number of false positives. Some patients may find this easier to use than traditional FOBT, as only two samples are necessary and vitamins and foods do not affect the test. However, as with traditional testing, FIT cannot detect tumors that are not bleeding.