The thyroid stimulating hormone (TSH) test was developed in the early 1970s to help diagnose thyroid conditions. I have been writing about the problems with the TSH test for nearly 20 years.

Before developing this “gold standard” test for detecting a thyroid problem, physicians determined thyroid levels the old-fashioned way: They sat down with their patient, took a detailed history, and performed a physical examination.

If a doctor suspected a thyroid problem, he or she would give the patient a therapeutic trial of thyroid hormone. The dose would then be adjusted depending on how the patient responded.

Although this approach was not precise — it depended on the doctor’s clinical judgment — multiple studies indicated that it was effective for many people with thyroid disorders.

Yet when the TSH test was introduced, medicine abruptly changed its views about how to diagnose and even treat thyroid problems.

Now, doctors had a specific measure that could tell them how the thyroid was functioning.

But some doctors didn’t see it that way. Dr. Broda Barnes, a family practitioner who specialized in diagnosing and treating thyroid problems, recognized the fallacy of relying on the TSH test shortly after it was released.

In 1976, Dr. Barnes wrote, “Forty percent of the American people — four of every ten children and adults — today are suffering needlessly and many are dying for lack of an ingredient vital for health. Is the ingredient unknown? No. Or unavailable? No. For years, medicine has recognized the role of the deficiency in some areas of health and disease and has had clues to its great importance in many other areas. But the knowledge too often has not been used — and still is not being used — because of the unreliability of laboratory tests. [These laboratory tests] have failed to show the deficiency even when doctors could see its manifestations clearly enough in patients before them. And while laboratory tests have erred and have misled both doctors and patients, patients have suffered.”

Dr. Barnes predicted that if doctors stopped relying on their clinical and physical exam skills, the number of patients suffering from thyroid disorders would increase dramatically.

Unfortunately, his predictions have come true. That’s why today we have an epidemic of patients suffering from thyroid disorders.