Dangers of medical tests

The dangers of medical tests is not something that many people consider.

We tend of think of medical tests as being helpful and even necessary. At worst, we consider them to be harmless. After all, it is only a check-up.

But what happens after that is another matter. Because medical tests often leads to medical treatment. Therein lies the dangers of medical tests – they expose us to the dangers of medicine, as you will discover in this article, originally published in a 1993 issue of The Good Life.

Here is the original article, titled…

When ignorance is safer!

Some people are afraid to go for medical check-ups. They worry that the doctors will find too many things wrong with them; they rather live in blissful ignorance. They have reasons to worry. Because unnecessary medical tests can do more harm than good.

Dangers of medical tests: Horror stories

Horror stories abound...

Of healthy individuals who go for a routine check-up, discover they have cancer, undergo treatment, and die within six months.

Of expectant mothers who are told after an ultrasound scan that their babies are severely deformed. Doctors advice them to abort. Reluctantly, they agree, only to discover too late that the baby was actually normal.

A lot more stories go untold...

An executive visits his doctor, who finds that his blood pressure is elevated. The doctor prescribes some drugs. The executive loses his sex drive. His doctor did not say this is a common side effect of the drug. The executive blames it on office stress… And so on.

Dangers of medical tests: False positives

In Medical Care Can Be Dangerous to your Health, Eugene Robin explains how a seemingly harmless medical test can lead to disastrous results. Worse of all, the test may even be hailed as a medical victory.

His example is hypothetical. The numbers are arbitrary. But it is the sort of thing that does happen.

Cancer of the pancreas, Dr Eugene Robin points out, is a rare disease that is difficult to detect. Suppose a blood test is developed in which a positive result indicates pancreatic cancer while a negative result indicates no cancer.

Ten patients known to have the cancer undergo the test and all ten produce positive results. The test works.

Ten controls, believe to be normal, undergo the same test. Nine produce negative results while one produces positive results. The test is repeated several times. Always, 10 percent produce positive result.

These people are assumed to be “false positives”. They don’t have the cancer, but for some reason or other, they test positive. This is not unusual. No test is perfect.

Suppose the test is now given to one million people. Cancer of the pancreas is quite rare, so only 50 people with cancer are detected. They undergo surgery. Two die during surgery – which is not many.

Another 20 die because their cancer is too advanced. All in, 22 patients died. The test saved 28.

Dangers of medical tests: Subjects become patients

But look what happens to the far lager group, Dr Eugene Robin urges. Ten percent of one million people – 100,000 people – have produced false positive results.

These 100,000 people are now frightened. They don’t know for sure if they have pancreatic cancer. So they undergo further tests. They have now become patients.

Suppose 10 of them died during further testing. Ten deaths out of 100,000 patients is considered very few.

We are now left with 99,990 patients. Eventually, all of them undergo surgery to find out whether or not they have the cancer. In the process, another 300 dies.

In the end, the test saved 28 lives but killed 310.

Dangers of medical tests: False success

But what do the medical experts say? Experts in the field of pancreatic cancer say the test is a big success. It has led to an important decrease in deaths from pancreatic cancer. The news creates a big stir.

Experts who study deaths from unnecessary testing and surgery, however, have no news to report. After all, 310 deaths out of 100,000 patients is nothing remarkable. In fact, the death rate of 0.31 percent is remarkably low.

Meanwhile, the test has caused endless anxiety among the 99,690 “false positives” who survived. They still don’t know for sure if they have the cancer. Some might commit suicide. These cases are not monitored.

And that is the whole trouble. While the benefits are frequently touted, the risks are not clear. But they are real.

Dangers of medical tests for the patient

The doctor who administered the test would feel that he saved a life. He would recommend the test highly.

If you have a friend who was saved by surgery as a result of the test, you would not believe that the test may be harmful. You would say that critics are, as usual, being alarmist!

If you have a friend who died from surgery, you would probably not blame the test either. Because you do not know about false positives.

More likely, you would think that doctors tried their best, but failed to save him from cancer.

Dr Eugene Robin asks: “Suppose you were the patient. How would you feel about the test? If you were the patient that died, your feelings would be irrelevant.”