Laboratory diagnosis of Lyme neuroborreliosis is influenced by the test used: comparison of two ELISAs, immunoblot and CXCL13 testing.

Purpose: To compare Borrelia-specific intrathecal antibodies by two different ELISAs, an immunoblot (IB) and CXCL13.

Methods: Twenty-seven adults and 23 children with clinical symptoms compatible with NB were tested for Borrelia-specific intrathecal antibodies by flagellum ELISA-AI (flELISA), a recombinant ELISA-AI (rELISA) and by IB. Patients were classified according to the European Federation of Neurological Societies (EFNS) criteria as definite NB, possible NB, or non-NB. CSF CXCL13 levels were measured by ELISA.

Results: Among 50 patients, definite NB was diagnosed with the rELISA-AI in 29 (58%) patients, confirmed by IB in 19/29 patients, with flELISA-AI in 17 (34%) patients, confirmed by IB in 15/17 patients, and with IB in 20 (40%) patients. CXCL13 was positive in 22 (44%) patients. In 4 of 8 patients with negative AI, IB showed many detectable bands both in the CSF and serum.

Conclusions: The diagnosis of NB strongly relies on the used test method. The rELISA-AI test appears to be the most sensitive while the flELISA-AI is the least sensitive. However when the ELISA-AIs were confirmed by IB, different patients were identified as NB, while only 26% were identified by all performed test methods. There is a demand for standardized test methods with well-defined sensitivity and specificity to establish validated diagnostic criteria for NB including the use of the IB assay and CXCL13 as an additional non-Borrelia specific determinant in early NB.