About 52,000 Americans died last year of colorectal cancer, cancer of the colon and rectum. Almost twice that number of persons developed the diesase, and the American Cancer Society estimates about 400 Washington area residents will develop it this year.

The cancer affects men and women, blacks and whites, in roughly equal numbers. Ninety-seven percent of its victims are 40 years old or older. It is the single most common form of internal cancer, and experts predict the death rate from it could be cut in half by yearly detection and treatment.

Beginning today, the local chapters of the American Cancer Society are distributing free take-home tests for colorectal cancer in all the chain drug-stores in the Washington metropolitan area.

Two hundred thousand of the tests, which can potentially reduce the fatality rate for colorectal cancer from 75 to 25 percent, will be available at all Peoples, Drug Fair, Dart, Rodman's and Giant Pharmacies, as well as at about a dozen independent pharmacies.

The test is a simple, painless, private way to detect blood in stool, the earliest sign of the internal bleeding often associated with cancers of the rectum and colon.

The test kit consists of a cardboard folder the size of a large package of safety matches, a small wooden stick and a stamped, return envelope addressed to the American Cancer Society.

All one has to do to take the test is use the stick to obtain a small sample of one's stool, smear the small sample on two paper "slides" in the carrdboard folder, seal the folder, place it in the envelope and mail it. One need not touch the stool or worry about any sort of self-examination.

The American Cancer Society will test the samples for any significant traces of blood, and in any cases where blood is found, the person will be notified and asked to take a second test while on a special meat-free, high-bulk diet. Persons whose second test turns up positive will be asked to see their physicians for further examination. Those who do not have a physician and cannot afford testing will be tested free at Georgetown, George Washington, or Howard university medical centers.

The Cancer Society has been distributing the tests through hospitals since November, 1976. Fifty thousand of the kits have been distributed and 23,000 persons have actually taken the test.

Of the 23,000 Washington area residents who took the test, 12 were eventually found to have cancer and 32 had precancerous conditions.

In its very early stages, colorectal cancer may not cause any obvious symptoms, which is why this blood detection test can prove to be soimportant.

The more obvious symptoms of the disease include anemia, a persistent change in bowel habits, a decrease in the size of the stool and or an increase in intestinal gas causing discomfort or pain.