Le test Hemoccult II, also called guaiac test, makes it possible to detect the presence of blood in stool and therefore the possible presence of a tumor colorectal. Since 2009, this colorectal cancer screening has been systematically offered in France, from the age of 50, and up to 74, every 2 years.

This test has been replaced since May 2015 by a new immunological test more sensitive, which would detect 2 to 2,5 times more cancers and 3 to 4 times moreadenomas.

Colorectal cancer is the second most common cancer in women behind breast cancer, and it ranks third in men, behind prostate and lung cancer. Its importance justifies the establishment of a large-scale screening test in most Western countries. In Quebec, on the other hand, this screening is not yet systematic.

The test is prescribed by the doctor, but it is performed by the patient himself at home. The goal is to detect the presence of blood in the stool. The patient must take samples from 3 successive stools (6 samples in all).

The procedure is as follows:

• choose a clean, dry container to collect your stool (a plastic bag or newspaper for example)

• take a sample the size of a grain of rice with a stick and place it in the center of the first frame of the first wafer. Do the same to fill the second frame of the first plate, and repeat the whole thing twice with two other saddles to fill the other two plates. A maximum period of 10 days must be observed between the first sample and the sending of the test.

• put the three blisters and the completed identification sheet in a medical envelope provided for this purpose and send it to the laboratory

The new immunoassay has the advantage of requiring only one stool sample.

In 97% of cases, the test is negative. No presence of blood was detected. Note that some polyps or cancers do not bleed when the samples are taken and are therefore not detected by the test. The patient will receive an invitation to repeat the screening two years later. If before these two years, the patient has digestive disorders (presence of blood in the stool, sudden change in transit, or persistent abdominal pain), then it is advisable to consult a doctor who can establish a diagnosis.

In 3% of cases, the test is positive. But be careful, this does not necessarily mean that the patient has cancer. However, it is necessary to consult a doctor (a gastroenterologist), who will prescribe a colposcopies (examination of the entire lining of the colon using an endoscope) to ensure the absence of colorectal cancer.