Dr. Bartley Cryan:

A positive result has been obtained but the relevance of the positive result is the issue. There are false positives and false negatives and the activated lymphocyte assay is not internationally standardised and is not recommended by the IDSA or the CDC in the United States. For these reasons we do not use it, because it is not an internationally approved assay.

To answer the question on antibiotics, if I phone a general practitioner with a strong positive result for somebody with a facial nerve palsy, which is one of the neurological manifestations which comes on reasonably early in Lyme disease, it will be sent to the reference laboratory. I know it will take three weeks to come back so I will suggest the patient is treated so the Lyme disease will be treated as early as possible. The result from the reference laboratory is likely to be positive and the person will have completed treatment by the time the result comes back. If the result is not confirmed then the facial palsy has another cause, although we would repeat the serology six weeks later to be sure. If it is Lyme disease, it will have been treated as early as possible, which reduces the long-term complications.

There is a suggestion that if someone with an infective illness is treated early, the antibody response can be blunted so the person does not develop as many antibodies as would be the case if he or she got the full disease. This is in theory, but in practice it does not really happen. Many people are well treated for infections but they still have many antibodies.