MEDICAL TESTS – What You Should Know

What your health care practitioner must tell you about medical tests

     Your health care practitioner has an obligation to tell you everything about each test, both good and bad, before you undergo it. That means you can ask about how reliable and accurate the test is, any harm or negative effects of the test such as pain or additional conditions that could occur as a result of the test, what he hopes to accomplish by having you take the test. Also ask: “What will you do if the test is abnormal?” and “What will you do if the test is normal?” If you get the same answer to both questions, then ask, “Then why do the test?”

What can affect the outcome of medical tests?

     Because certain foods, medicines, and/or vitamins can have a negative effect on the test. Your health care practitioner should ask you about each of these prior to telling you to have a test. This is not always done and the results can be disastrous. Always ask if what you’re eating or taking can affect the results of a test if your health care practitioner doesn’t bring it up.

How reliable are medical tests?

     Be aware that tests vary in reliability. Some tests have very low reliability. That means you can’t rely on the results. You can never be sure that any single medical test, or even a single battery of medical tests, is reliable. Reliable means you get consistent results over time or over tests or over people doing the tests. No test is 100% reliable, so you can get a false positive (showing you have something when you don’t) or a false negative (showing you don’t have something that you do).

What’s more reliable than medical tests?

     Because of this reliability problem, never regard a test as anything more than a means of confirming what can be observed clinically: your symptoms, the physical signs you exhibit, your family’s medical history and your health care practitioner’s impressions.

What if your medical tests don’t jibe with your symptoms?

     Avoid undergoing therapy or treatments if the tests don’t support clinical information, such as your symptoms, how you feel, etc. Never change your entire lifestyle based on the results of one test. Make sure you have the test repeated at least twice, and in different settings (another laboratory or another practitioner’s office that isn’t affiliated with your practitioner.

How reliable are medical laboratories?

     When medical laboratories were tested for accuracy, more than 1 out of every 7 tests results were found to be either in error or totally unreliable. That means millions of tests performed every day are inaccurate. Many of these inaccuracies occur because the testing chemicals are defective because they’re out of date, contaminated or mislabeled, according to the Food and Drug Administration.

     A study performed by the Centers for Disease Control found that only 5% of one test were accurate; 95% were inaccurate and gave the wrong diagnosis to the people having the test.

     A biochemist at Sloan Kettering Hospital sent slides to laboratories around the country. Fifty percent of the labs made a wrong diagnosis; that means every other person got the wrong diagnosis.

How valid are medical tests?

     Even when a test is preformed correctly, the results may not be valid. Every test can be evaluated based on its sensitivity (the ability to detect a disease). No tests are 100% sensitive. But even tests with 80% sensitivity mean 20% of people having the tests will get the wrong results. For example, the stress electrocardiogram fails to show potential abnormalities or identifying existing heart disease in more than half of all tests! This is worse than a guess, which is theoretically correct 50% of the time.

     The second criterion for evaluating lab tests is specificity. This percentage tells the test’s ability to show a negative or normal result when the condition does not exist in the person being tested. A test with an 80% specificity rating will give a false positive negative result 20% of the time; this means 20 out of every 100 people having the test will get a false positive results.

     There are other statistical ways to look at tests. It’s most important to remember that no test is 100% accurate, so don’t have surgery or take an experimental drug or one with many nasty side effects based on one test.

How reliable are blood pressure, electrocardiograph and X-ray machines?

     One study found that 1 out of every 2 blood pressure apparatuses gives the wrong reading, usually on the high side.  Similar studies found that thousands of electrocardiograph machines are improperly calibrated. The other problem with electrocardiograms is that they and fail to detect heart problems in a great many patients (poor sensitivity) and falsely indicates heart problems in many other people (poor specificity), so it has a very low predictive ability and low accuracy. X-ray machines are often operated by improperly trained technicians that produce faulty or ineffective pictures.

What are the dangers of medical tests?

     No medical test is without risk, be it some devastating side effect, such as an allergic reaction, an infection, or excruciating anxiety wondering how long you have to live based on a false-test death sentence.

    Many tests have insignificant results and may not point to specific diseases. This can cause a great deal of anxiety and even physical reactions if test results are accepts at face value. The more tests you have, the more potential for negative results. More importantly, treatment, even surgery, may be instituted for a condition that does not exist. This is the ultimate danger of medical testing.

Why are so many medical tests performed in the United States?

     So many tests are performed in the U.S. because we operate on a fee-for-service system. When compared to British physicians, U.S. doctors order 40 times more tests than their London colleagues.  This is because U.S. doctors are paid for each and every test they order, doctors where national health insurance exists, are not.

     Because physicians and medical centers buy expensive equipment for stress tests, X-rays, CAT scans, MRIs, etc., they must perform many tests to pay for that equipment, whether the test is valid or not.

     Medical tests are the largest single health cost item and account for the largest portion of a hospital bill. Medical tests provide the greatest source of income for hospitals, which is why many of them demand that every patient undergo a battery of tests upon admission, even though they may have been performed the day before in a doctor’s office or a laboratory. Medical tests are also a great source of income for physicians.

     Younger physicians are more apt to prescribe medical tests, substituting the results for the observations of experience. It used to be that doctors questioned and examined their patient far more carefully and applied testing only to confirm their suspicions. Today, the tests come first and results, not your complaints guide therapy.

     Up to 80% of physicians in the U.S. practice defensive medicine, ordering unnecessary tests to protect themselves from possible law suits.

What is the effect of unnecessary medical tests?

     One study showed that only 5 percent of all lab tests actually results in altered patient care or had any impact on a patient’s diagnosis or treatment. Several studies revealed that a great many doctors never even look at the reported results of medical tests after they have been recorded on the patient’s hospital chart.

     A major effect of unnecessary medical tests is the increased cost of medical care by hundreds of billions of dollars a year. If you have health insurance, you probably think it’s not costing you anything, so why not have the test? The answer is employer’s  payments for workers’ health care are reflected in the cost of merchandise. So, in reality, you are paying for the tests, even though they seem to be free.

What is iatrogenic disease?

     Iatrogenic disease means the cause of the disease or suffering came directly from the health care practitioner’s actions or words, not from any germ, improper living, or genetic defect. The actions could be unnecessary surgery, ordering the wrong drug or the wrong dosage of the drug, or giving improper counsel.

     For every 7 medical tests you have, you will receive at least one false-positive result, indicating the presence of a condition or disease when none exists.

Invasive vs. noninvasive medical tests

     Invasive tests penetrate the skin or body orifices (openings). It’s always more risky to have an invasive medical test. If your health care practitioner orders one, ask if you can have a noninvasive test instead.

     An invasive test itself is sufficient to produce a false-abnormal test result where no abnormality exists. This is strong evidence for choosing noninvasive tests.

Should you have medical tests offered at health fairs?

     Bear in mind that in one study, 2 out of every 5 tests (blood pressure, blood sugar, etc.) had at least one false-abnormal test result at health fairs. If you test positive, you can waste a lot of money trying to refute or validate that result with your physician or health care practitioner.

     Also remember that when you volunteer to take a medical test at a health fair, whoever administers the tests is under no obligation to warn you of related risks associated with the test(s).

What should you do if your health care practitioner suggests you have surgery or take medicine based on a medical test result?

     Don’t worry about the results of one test, especially if it doesn’t agree with your symptoms. Just have the test performed by another practitioner in another office and compare the two. If necessary, have a third opinion. Most health insurance programs will pay for at least one second opinion; some pay for two.

What are your legal rights regarding medical testing?

     Under the law, a mistake in medical testing is negligence on the part of the testing facility or health care practitioner.

     When you undergo a test, you the right to know it was conducted with absolute accuracy, what the test is supposed to detect, how well it should perform, any dangers, and what the results mean to you.

     When you health care practitioner orders a test, that amounts to implied warranty that the people and machines or chemicals used are correct. Any error, no matter how slight, is not to be tolerated. You should be compensated for any error monetarily.

     What if you were told you had high blood sugar and it turned out the lab technician left the tourniquet on your arm too long (causing erroneously high blood chemistry results), or what if the lab tech left your blood sample standing around too long and your blood-sugar level was report as low? Either result can cause extreme emotional and/or physical results in you.

     Remember: a clinical lab should repeat any test without charge if you feel the test does not reflect your symptoms or your health care practitioner’s suspicions.

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