As a physician, I think Cathey Pinckney and Edward Pinckney should be congratulated on their article pointing out two of the causes for the high cost of health care in this country -- unnecessary tests ordered either for the doctor's profit or to try to protect against subsequent litigation {"Needless Medical Tests -- A $50-Billion Boondoggle," Outlook, Aug. 16}. Inadvertently, they have pointed to a third cause: the failure of people to realize that their attitude toward monetary compensation for medical errors brought on by the patient's own stupidity -- or, as they put it, ''masochism'' -- is directly responsible for the legal malpractice chaos.

In the first paragraph of the article, they suggest that the patient was determined to find something medically wrong and that he refused to accept good advice from his doctor. The patient insisted on having a second doctor, who, on the basis of a test of questionable reliability, suggested the medical abnormality that the patient subconsciously wished for and suggested a change of life style. In the last sentence of the article, they state that the patient received ''well-deserved'' monetary compensation for his misery brought on by the misinterpretation of the test. Nothing is further from the case.

To compensate a patient for an error brought on as much by the patient's own attitude of distrust and insistence on finding a specific cause of his symptoms as by the doctor's error is totally unjustifiable. This patient contributed significantly to his own misfortune and was at least as responsible for his misery as was the doctor who misinterpreted the test. Whatever happened to the doctrine of caveat emptor?

It is incredible that intelligent people such as the authors of this article can fail to realize that it is this attitude toward compensation for misfortunes befalling patients that increases costs. Errors of judgment in the practice of such an inexact science as medicine are inevitable. Massive monetary awards to the unfortunate lead only to an escalation of malpractice insurance rates, more unnecessary ''defensive'' testing and increased costs passed on directly or indirectly to all of us.

Malpractice needs to be redefined. It was never considered to be synonymous with an honest error of judgment. Some patients do bring on their own troubles. They should not be generously compensated for so doing.

N. K. CONNOLLY

Washington

Cathey Pinckney and Edward Pinckney, by inflating half-truths and atypical cases, have overwhelmed a few kernels of fact with anxious hyperbole and diverted needed attention from important truths. Their article may help them sell their book, but it won't help anybody else.

One kernel of fact is that diagnostic tests are not 100 percent accurate. Another is that even in the very high percentage of cases in which tests are accurate, they do not lead automatically to treatment. These kernels should not obscure the fact that medical tests, when given proper weight by a skilled physician, yield important medical information and save and improve lives.

Mammograms, for example, can detect breast cancer while it is still curable. Millions of people have been saved from blindness by glaucoma testing. AIDS screening has decreased exposure to the virus through contaminated blood donations from one in 2,000 to one in 500,000. And every winter Strep tests help decide whether a schoolchild needs antibiotics or just rest, lots of orange juice and TLC.

Yes, tests should continue to be improved in sensitivity, variety and reliability. Just because they have never been better doesn't mean that we should rest on yesterday's laurels. And, yes, physicians, laboratories and patients should understand more about when tests are and aren't needed and about their uses and weaknesses.

All of this is a tough challenge. It calls for thoughtful action, not just alarmist rhetoric.

FRANK E. SAMUEL JR.

President, Health Industry Manufacturers Association

Washington