DIAGNOSIS AND TESTING|
Lyme Disease can be hard to diagnose. Less than one third of victims remembered having a tick bite and half of all people with Lyme Disease never had or do not recall, having a rash. You should have a complete history and physical exam by a doctor familiar with the disease and the blood tests needed to diagnose the disease.
The best time to have the blood test is six weeks after being bitten by the tick if there are no symptoms present. Your body takes about this long to form the antibodies to the disease that the test is looking for. If symptoms do exist this is a sign that your body is trying to combat the disease and the test can be done sooner.
There are several blood tests for Lyme Disease and they can be very difficult to interpret. The first test is a Lyme titer which looks for antibodies in the blood. These antibodies can mean that you have a current or past infection. The results can be positive, negative or equivocal, (which means borderline). An equivocal result should be repeated in two to four weeks to see if there is any change. Since antibodies to other infections may look similar to Lyme Disease antibodies a “false positive” result may occur. “False negative results may occur under the following conditions:
There can be no comparison from one test to a repeat test because the lab performs these tests against a “control” which changes from batch to batch. Therefore, you cannot see if the titers are rising or not. The only way they can be compared is if the same lab froze one of the samples and then ran both samples in the same batch. A Lyme titer may remain positive for a long time even after antibiotic therapy has been completed and this does not mean there is still active disease.
- The test may have been done before the body has had a chance to make antibodies.
- Antibiotics taken in the early stage of the disease may prevent a person from ever making antibodies.
- If the test is taken after a course of antibiotics there may be a decrease in the level of antibodies present.
This test looks at the specific parts of the bacteria to which antibodies attach. This test is more specific and less affected by antibiotic treatment. These are also reported as positive, negative or equivocal. An equivocal result should be repeated in two to four weeks. This test is done along with the Lyme titer since to detect a “false positive” result from the titer.
Joint fluid can also be tested and can be either positive, negative or equivocal. This is done for patients with arthritis to see if the arthritis is being caused by Lyme Disease.
Fluid obtained from a spinal tap can also be tested for Lyme Disease. The titer and the Western blot tests are performed on the fluid to see if neurological problems are caused by Lyme Disease.
POLYMERASE CHAIN REACTION (PCR) TESTING
This test identifies DNA found in Lyme bacteria and is a very sensitive test.
This test can be performed on blood, joint fluid, cerebrospinal fluid and urine. This is a new procedure and can cause false positive results if not done correctly. This test shows bacteria is or was in the sample but does not mean there is an active infection.
Remember: Testing for Lyme disease is very complex and needs interpretation by a physician familiar with the disease.
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