Lyme disease - Diagnosing Lyme disease
- Introduction
- Symptoms of Lyme disease
- Causes of Lyme disease
- Diagnosing Lyme disease
- Treating Lyme disease
- Preventing Lyme disease
- See what the doctor sees with Map of Medicine
Lyme disease can be a difficult condition to diagnose, particularly in its latter stages. This is because its symptoms are also shared by more common conditions such as infections and arthritis.
A characteristic pink or red "bull’s-eye" rash of Lyme disease may develop, usually within 30 days of being bitten. However, in up to a third of cases of Lyme disease, there is no rash.
If you do not develop a rash, but develop later symptoms of Lyme disease, such as joint pain or flu-like symptoms, let your GP know if you've spent time in woodland or heath areas where ticks are known to live.
If it's possible or likely you were bitten by a tick, your GP should refer you for tests to confirm or rule out Lyme disease.
Testing
Tests for Lyme disease need to be carried out at least a few weeks after you were bitten by the tick because it can take this long for the infection to develop. You may need to be re-tested if Lyme disease is still suspected after a negative test result.
The tests used to help diagnose Lyme disease are:
- enzyme-linked immunosorbent assay (ELISA) test
- Western Blot test
These are described below.
ELISA test
The first test you will have is a type of blood test known as an enzyme-linked immunosorbent assay (ELISA) test. The ELISA test looks for specific antibodies produced by your immune system to kill the Borrelia burgdorferi bacteria.
The ELISA test is not 100% accurate as it can sometimes produce a positive result even when a person is not infected with Lyme disease (known as a false-positive result). This may happen if a different condition is causing your symptoms, such as syphilis, glandular fever or rheumatoid arthritis.
Because of this, a positive ELISA test is followed by a further test known as the Western Blot test.
Western Blot test
The Western Blot test involves taking a small blood sample. The proteins in the blood are separated and placed on a thin sheet of permeable material. The proteins can then be studied for antibodies used by the immune system to fight the bacteria Borrelia burgdorferi which causes Lyme disease.
If both the results of the ELISA test and the Western Blot test are positive, a confident diagnosis of Lyme disease can usually be made.
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