Medical Test Results: Are You Normal, and Is That a Good Thing?
Last reviewed by Faculty of Harvard Medical School on January 13, 2011
By Robert H. Shmerling, M.D.
When doctors talk shop, they often use terms to describe an examination or test result by comparing it to "normal." While this might seem straightforward, health care professionals use several expressions that might confuse you if you aren't prepared. Read on to learn how to interpret what your doctor is saying when he or she sends you a note, calls you or talks with you in the office about the results of your evaluation.
Fortunately, in the majority of doctors' practices, the most frequent result of an examination or testing is "normal."
I recall having a throat culture performed at the college infirmary; when I stopped by to get the results, the physician simply pointed to the actual report from the laboratory: It read "Negative" in bold letters. That worried me, because I thought that "negative" meant something bad and that a positive result was a good thing.
In fact, when reading medical results, it's usually the opposite; with rare exception, "negative" is normal (because it means that an abnormal result is not present) and "positive" is abnormal or unusual (because it means that something out of the ordinary is present).
There are several ways health care professionals express normalcy. These include:
Frequently, when the results of an examination or a test are not normal, the abnormality is minor and has little or no bearing on your health. So, health care professionals have several ways to express a result that is not normal, but often provide descriptive detail to specify just how abnormal or concerning it is.
For some tests, such as blood counts, the result is high, low or normal. For others, such as an X-ray, results may show an abnormality of little importance, such as a speck of calcium in the lungs or scarring from past pneumonia. It is not rare that the importance of an abnormality is not known right away and that more testing or the passage of time is needed to know for sure how meaningful it is. Examples of ways an abnormal examination or test results might be expressed by a health care professional include:
There are times when a result that is out of the normal range is a good thing and what is usually considered "normal" is bad. For example, if you are taking the blood thinner warfarin (Coumadin), the test that measures blood clotting, (called the International Normalized Ratio, or INR) should be elevated; it indicates that clotting of the blood is less likely, a good thing for people who have had problems with blood clots. Getting the blood "thinner" and less likely to clot is the reason people take warfarin. While the urgency depends on the reason you are taking warfarin, a normal result is not a good result; it indicates that the medication is not thinning the blood enough. Another example is a pregnancy test; if you are trying to become pregnant, a "positive" result (indicating that you are pregnant) is a good thing and a negative result may be cause for disappointment.
A key part of understanding one's test results is knowing what the test is supposed to do. When I learned that my throat culture was "negative," that only meant I was less likely to have strep throat. There was still a small chance I had strep infection (because the test isn't perfect), and I could still have another cause of a sore throat, such as a viral infection or even a bacterial infection other than strep. The test did not mean I was healthy; it could only help to make one diagnosis (strep throat) more or less likely. Asking your doctor about the purpose of your tests may help you to understand their results.
The real significance of any particular test result depends on numerous factors, including why it was ordered, what is normal or usual for you, whether the test result is getting better or worse, whether your condition is getting better or worse, how abnormal it is, and whether it may even represent an error in the test (rather than a disease in you).
But, don't be disappointed if your examination is "unimpressive" or your test results are "unremarkable." When you are under medical evaluation, those findings are often the best you can have. On the other hand, if your results are abnormal, do not panic; your doctor cannot be positive that your positive results indicate a negative health outcome. Sometimes the most difficult part about getting your results is figuring out what your doctor is saying.
Robert H. Shmerling, M.D., is associate physician at Beth Israel Deaconess Medical Center and associate professor at Harvard Medical School. He has been a practicing rheumatologist for over 20 years at Beth Israel Deaconess Medical Center. He is an active teacher in the Internal Medicine Residency Program, serving as the Robinson Firm Chief. He is also a teacher in the Rheumatology Fellowship Program.