WHAT IS A LABORATORY TEST?
A laboratory test is a medical procedure that requires a sample of blood, urine, tissue or substance in the body to check for certain features, changes or critters (bacteria or viruses). Lab tests are typically used during routine checkups to identify possible changes in a patient's health status before any symptoms appear. They are also used to diagnose a condition while a patient is experiencing symptoms.
E.g. - This is why I always say you never just wake up with the flu because your body has been carrying around the virus before it manifested into full blown flu. This would have been revealed in a laboratory test.
A doctor will use your lab results to help plan your treatment, evaluate your response, monitor your treatment and the course of your condition over a period of time.
Laboratory test samples are analyzed to determine whether the results fall within normal ranges. They also may be checked for changes from any previous tests.
Keep in mind, normal test values are usually given as a range, rather than as a specific number, because normal values vary from person to person. What is normal for one person may not be normal for another person. Many factors including the patient’s sex, age, race, medical history and general health can affect test results. Sometimes, test results are affected by specific foods, any drugs the patient may be taking and how closely the patient follows pre-test instructions. That is why a you may be asked not to eat or drink for several hours before a test. It is also common for normal ranges to vary somewhat from laboratory to laboratory.
"A cup of coffee reduces iron absorption by 39 percent, and a cup of tea will reduce it by 64 percent. Drip coffee will lower iron absorption by 72 percent, while doubling coffee's strength will reduce it 91 percent! In comparison, orange juice with its vitamin C, may increase iron absorption in a meal by 250%!" Am. J. of Clinical Nutrition 37:416-420,1983; ibid 32:2484-2489,1979
E.g. - My girlfriend Julie and I went to give blood. Just before we left to give blood, we knew drinking liquid was important, so I drank 16 ounces of water and Julie drank 16 ounces of tea. Needless to say, Julie was turned down to give blood due to a low iron count, due to the affects of the tea. A couple of days later, she was cleared to give blood.
Some laboratory tests are precise, reliable indicators of specific health problems. Others provide more general information that will give a doctor clues to possible health problems. Information obtained from laboratory tests may help doctors decide whether other tests or procedures are needed to make a diagnosis. The information may also help the doctor develop or revise a patient’s treatment plan. All laboratory test results must be interpreted in the context of the overall health of the patient and are generally used along with other exams or tests. The doctor who is familiar with the patient’s medical history and current condition should explain the test results and their implications to the patient.
Laboratory tests are tools helpful in evaluating the health status of an individual. It is important to realize that laboratory results may be outside of the so-called "normal range" for many reasons. These variations may be due to such things as race, dietetic preference, age, sex, menstrual cycle, degree of physical activity, problems with collection and/or handling of the specimen, non-prescription drugs (aspirin, cold medications, vitamins, etc.), prescription drugs, alcohol intake and a number of non-illness-related factors. Any unusual or abnormal results should be discussed with your physician.
It is NOT possible to diagnose or treat any disease or problem with a blood test alone. Blood tests can help you learn more about your body and detect potential problems in the early stages when treatment or changes in personal habits can be most effective.
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**This web site's goal is to provide you with information that may be useful in attaining optimal health. Nothing in it is meant as a prescription or as medical advice. You should check with your physician before implementing any changes in your exercise or lifestyle habits, especially if you have physical problems or are taking medications of any kind.
