Laboratory Tests: Definition, Reasons, and Procedures
What are laboratory tests?
Laboratory tests are medical procedures that are ordered by your doctor and involve the examination of small samples of urine, blood, or other bodily fluids, tissues or other substances found in the body.
A medical test is a procedure used by medical professionals to diagnose, detect or monitor diseases, a person’s susceptibility to diseases, disease processes and, most especially to find out what treatment is best suited for the patient. Most medical diagnostic tests are usually performed in a medical laboratory.
There are various types of medical tests based on what their test results will be used for, and these are diagnostic, screening, and evaluation. But for this article, we will be talking about diagnostic tests.
A laboratory test is a medical procedure that is used to confirm or determine the presence of a condition or disease in an individual. These tests are performed on the individual after having been suspected of having the condition, based on the symptoms he or she has shown, and can also be based on the results of previous related medical diagnostic tests.
Why does your doctor need lab tests?
Doctor's need the information they obtain from laboratory tests for many reasons. The results of these tests can help your doctor to:
- know if your health is changing, even before you have any symptoms
- diagnose a condition or a disease
- plan your treatment, for example, know what medication to prescribe for you
- find out if your condition is improving
- monitor your health over long periods of time
How are the tests analyzed?
After the specimen or sample is collected, it is sent to a lab. These laboratories run specific tests on your sample to measure its response, if any, to certain substances. Reactions or lack of a reaction may mean you do or do not have a specific disease or condition. In other cases, the lab will compare your current results to prior tests to detect a change.
What do the tests reveal?
In most cases, laboratory tests indicate if your results fall within a normal range, rather than providing a specific number. This is because "normal" for one person may not be "normal" for someone else. Some lab tests are very specific and precise, and others are used as a more general indicator of potential health concerns. Doctors often will order additional tests based on the results of lab tests, as more information is needed before a diagnosis can be made.
What factors affect lab test results?
There are many factors that can influence the result of lab tests. These may include:
- general health
- medical history
- medications you are taking
- specific foods
- differences in laboratory techniques and procedures
Types of Laboratory Tests
There are many types of medical diagnostic tests that a doctor can prescribe to a patient, depending on the symptoms being shown and the condition which is being suspected that the patient has. Some of the most common medical diagnostic tests, however, are listed below:
- CBC or Complete Blood Count – is a common blood test that is performed to diagnose a variety of different medical conditions such as an infection or anemia. The test is performed by a phlebotomist (a medical specialist) and is done by taking a blood specimen from your body through your finger, a vein in your arm, and in the case of infants, in the heel.
- MRI or Magnetic Resonance Imaging – is an imaging test that takes pictures of the insides of your body. The MRI can be compared to an X-ray but is much more detailed, including not only bones but muscles, nerves, bones and other organs.
- CAT or Computer Axial Tomography Scan- another imaging test that takes pictures inside your body, and can let doctors find out tumors, blood clots, and infections, as well as other diseases and conditions.
- Electrocardiogram or EKG
- Prothrombin time
- Prostate Specific Antigen
- Bone Density Study
Risks of Laboratory Tests
Believe it or not, even medical diagnostic tests that are used to aid the treatment of a condition can also pose risks to the patient. Some medical tests are associated with health risks, which sometimes require general anesthesia. An example of this medical test procedures is a mediastinoscopy, a procedure that can visualize the insides of your mediastinum or the central part of your torso that contains various vital organs.
Although most medical tests, especially the basic ones such as blood tests and pap smears. do not really pose any risks whatsoever. What most patients need to worry about when it comes to medical diagnostic test risks, are the indirect risks it poses such as the stress involved in testing, and the continual testing into riskier test procedures as a result of false positive results.