There are many medical tests used to assess an individual's health. Such tests, called biomarkers, are used to diagnose the presence of illness, monitor treatment and recovery, and even predict an individual's susceptibility to disease in the future.
Biomarkers can range from blood pressure or pulse rate measurements, to urine or blood samples. The role and value of such diagnostic tests are fundamental to establishing a wellness baseline. There are biomarkers that nearly everyone who visits a doctor's office will encounter, but others that are ordered only when symptoms, or family or personal medical history suggest they might be necessary. In all cases, however, the more that patients know about these medical tests, the better prepared they will be to understand their current health and make choices that will enhance their wellbeing.
TheVisualMD has compiled a Biomarker Library that will demystify medical tests and serve as an invaluable reference guide. Each biomarker has been categorized under the organ system it applies to (for example, heart, liver, bone or kidney health), as well as listed alphabetically.
We are so used to seeing (at least on TV) medical lab specialists in white coats holding samples in test tubes that it's easy to believe that for anything that could possibly go wrong with our health, "there's a test for that." But in fact it has taken more than a century for researchers to devise the current battery of tests used to probe the workings of our bodies.
Biomarkers include substances that are naturally eliminated from the body, like urine and feces, or that be collected non-invasively, such as saliva, sputum (produced by coughing), secretions from the nose or throat, semen and secretions from the female reproductive tract. Swabs are used, but in some cases, containers are given to patients in which they collect samples themselves.
A few tests can be interpreted in a doctor's office almost immediately (a rapid strep test, for example, can confirm in minutes the presence of streptococcus bacteria that cause sore throats). Results from tests performed in hospitals are usually available within hours; results from tests sent to large laboratories may take a few days.
Diagnostic tests are rarely painful (invasive sampling techniques, such as biopsies, are performed with local or general anesthetic), but they may cause discomfort or embarrassment for some patients. Preparation can help minimize such issues, especially when samples need to be taken from children, the elderly or patients with special needs.
The first step is to understand why tests are being performed. Knowing the purpose of the test and its importance to a patient's well being is essential; understanding what the biomarkers will measure and how this information will be used in diagnosis or treatment is also helpful. Most adults get through their tests with little stress, emotional or physical; it's even easier when tests are seen as the critical first step in taking charge of one's health and well being.
Young children and the elderly pose special considerations, but in general, the same guidelines apply. Step one is still to understand the basic purpose and importance of tests. Especially for these populations, knowing what to expect can alleviate the anxiety and helplessness that may accompany medical tests.
The time it takes to get lab results will vary, depending on the test and whether it is done in a hospital or sent to a lab (in total, more than 15 million lab tests are analyzed each day in the U.S.). Once test results are available, the challenge is to make sense of them.
Explaining the results of diagnostic tests (and putting them into context) is the job of a doctor, physician assistant or nurse practitioner. But that doesn't guarantee patients will given all the information they need; in too many cases, conversations about test results don't go beyond general reassurance that everything looks fine or general concern that some numbers are either too high or too low.
No matter how good a communicator a healthcare practitioner is, patients who more fully understand the meaning and importance of test results will be in a better position to put this information to effective use in making decisions about their health and well being.
Results for lab tests are expressed in metric units or SI units (an updated version of the metric system, SI is abbreviated from the French, Systeme international d'unites, or International System of Units.
U an IU (units or international units) are measurements that have been agreed upon and standardized by the scientific and medical communities. An enzyme unit, for example, is the quantity of enzyme needed to cause a reaction to process 1 micromole of substance per minute under specified conditions. Units are also used to measure the activity (that is, the effect) of many vitamins and drugs. For example, 1 IU of insulin is 45.5 micrograms and 1 IU of penicillin is 0.6 micrograms. With vitamins, 1 IU is 0.3 microgram for vitamin A, 50 micrograms for vitamin C, 25 nanograms for vitamin D, and 0.67 milligrams for vitamin E.
A biomarker measures a physiological variable. Biomarkers are used to diagnose disease and evaluate the progress of treatment. They are also used to measure wellness and can provide benchmarks for personal health goals.
When you think of biomarker, think of biography and biology. Biomarkers tell the personal story of your biological health. Learn to understand and read your medical bio!