Diagnosis of Lyme Disease
To diagnose Lyme Disease the first indicator used is the bulls eye rash or erythema migrans. However less than 50% of patients with Lyme disease remember being bitten by a tick or having any rash. It is important to know that the bulls eye rash is a classic symptom of Lyme disease and no further testing is needed prior to starting an appropriate course of antibiotic therapy. Non presence of the rash should NOT be considered an indication that a patient does not have Lyme disease.
Official guidelines on diagnosing Lyme disease rely on a two stage testing. First an enzyme-linked immunosorbent assay (ELISA) test is done which looks for antibodies to the borrelia bacteria in the body. This test can show up negative during the first few weeks of infection until sufficient antibodies are produced. Chronic Lyme sufferers may also have a false negative result, due to the depleted immune system not being able to produce antibodies in sufficient numbers for the test to show positive. This poses a huge problem for patients who are infected by the disease but who get a falsely negative ELISA. If the ELISA shows a positive result then a 'Western Blot' test is done. This test also looks for antibodies but is much more sensitive than the ELISA test. If this is also positive then treatment will begin.
If you have been bitten by a tick, or if you think you have been bitten it is advisable to speak to your doctor as soon as possible. The key to treating this disease is an early diagnosis. If you are presenting any symptoms at all, seek medical advice!