Loading...
A positive antibody index (AI) differentiates intrathecal production of antibodies from extrathecal production with antibody diffusion into CSF. In this study, the diagnostic value of the AI was determined in 123 consecutive patients from a Lyme-endemic region of France with neurologic symptoms and Borrelia antibodies in CSF. Forty patients had clinically definite Lyme neuroborreliosis (LNB), 9 had clinically possible LNB, and 74 had other neurologic diagnoses (controls).
Thirty patients with definite LNB had positive AIs (sensitivity, 75%). Only two controls tested positive (specificity, 97%); both had previously had LNB. Five patients with possible LNB also tested positive. Twenty-two definite-LNB patients lacked CSF pleocytosis (55%; most…