At a time when health care experts across the nation are vigorously promoting self-help medical tests, an obscure Maryland health regulation, designed to protect the public, has severely hampered one of the American Cancer Society's major statewide cancer prevention programs.

The law directly impedes the society's screening program in which individuals can perform their own "hemoccult" test - an aid in detecting cancer of the colon and rectum.

The regulation does not prohibit the cancer society from distributing the tests, which people can give to themselves. But it does prevent the organization from reading the test slides. According to state rules, the slides must be read in a certified laboratory.

This year, therefore, the cancer society has had to hire a laboratory to read the slides at a cost of several thousand dollars, instead of using doctors and nurses who volunteered their services.

While the testing program has been curtailed in Maryland, it is continiung unimpeded in the District of Columbia and Virginia, where no such regulation exists.

Some Maryland health officials who support such free self-help tests as a means of detecting disease at an early stage and of cutting down health costs have criticized the state regulation as an example of how a law designed to help consumers has ended up hurting them.

"If we have to go out and hire professional expertise for (the programs) that the American Cancer Society is involved in, we could not continue," said James Woods, of the cancer society's Montgomery County unit.

In addition to the laboratory test rule, there is another state health regulation that prevents the American Cancer Society or any similar organization from releasing laboratory test results directly to patients. Instead, the results may be released only to a physician or a person authorized "to practice the healing arts."

Health Department officials say such regulations are necessary to ensure the quality of the tests and to prevent nonphysicians from giving out medical advice.

According to Dr. Robert I. Bosman of the State Health Department's laboratory division, a person who is simply informed that the results of his or her cancer test is positive, may become "unduly alarmed. The results must be interpreted by a physician," Bosman said.

According to Richard Chernela, spokesman for the cancer society in Maryland, the hemoccult test could have been distributed to about 25,000 Maryland residents. But now that the organization has to pay an additional $1 on each slide that is read in a laboratory, the society expects to reach only about 10,000 people, Chernela said.

Cancer of the colon and rectum is one of the most common forms of internal cancer, resulting in about 100,000 new cases each year and some 51,000 deaths annually. The cancer society's screening program, Chernela said, was an attempt to inform the public that hemoccult tests "are available . . . painless and simple."

In the past, the society simply informed individuals directly of laboratory test results. Now it sends post cards to the people who take the test, asking them to forward the name of their physician to the society.

In cases where the test results were positive, the society frequently contacted the physician anyway, Chernela said.

George Nilson, one of Maryland's deputy attorneys general, say the cancer society may be able to circumvent that regulation by having a physician associated with the organization give "blank authorization" for the test results to be released directly to the people who took them.

"We're thinking about going to the state to see if they can do something" to change the regulations, Chernela said.

Both Chernela and Nilson agreed that Maryland's health laws are a maze of complicated, often conflicting regulations. According to Bosman, the laboratory regulations do not affect other tests, such as blood pressure or eye exams. Nor do they affect some "do-it-yourself" tests, such as the Early Test for Pregnancy (ETP), which can be bought in most drug-stores without a prescription.

However, while community volunteers without medical training, may take your blood pressure and inform you of the results, they cannot diagnose high or low blood pressure or suggest treatment according to a spokesman from the attorney general's office.

Maryland is also currently working on setting up a series of controls over mobile health care units, such as those that show up often in suburban shopping centers or are hired by large firms to perform various tests and checkups on employes.

One of the proposed regulations would require that each of these units come under the direction of a physician who would be responsible for reviewing test results and ensuring that patients receive follow-up care from their physicians if need be.

Dr. Frances Norris, who is working on the regulations, said that under these conditions, there would be no reason why an individual could not receive the results of his or her laboratory tests directly.

If such regulations are adopted, Maryland would become one of only a handful of states that has taken steps o f license and regulate mobile health care units.