When is serologic testing indicated in the workup of Lyme disease?
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When is serologic testing indicated in the workup of Lyme disease?
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@habala Two-step testing is not indicated for patients with erythema migrans, because the rash may develop before the antibodies. Nor is it recommended for patients who have not been in endemic areas, because of the high false-positive rates in that setting. In addition, inadequate antibiotic therapy for early Lyme disease may fail to control the infection yet still suppress the antibody response, potentially yielding a false-negative result.
Western blot testing should be performed only in conjunction with antibody titer testing, and only as followup of a recent positive or equivocal ELISA titer. Ordering a “Lyme titer with reflex testing” ensures that two-step testing is performed properly.
In the United States, patients with extracutaneous involvement in the absence of treatment almost universally have positive titers. In Europe, negative serum titers have been reported in patients with neurologic Lyme disease that was confirmed by intrathecal antibody production.
The results of one study noted that differing sensitivity and specificity were found between various assays used to detect anti-Borrelia antibodies in patients suspected of having Lyme disease. False-positive results occurred in 7% of healthy controls in two of the eight ELISA assays tested. This variability makes it very difficult to compare results from different laboratories, both among different patients and in individual patients