The purpose of this study was to evaluate the diagnostic sensitivity and specificity of a commercial C6 enzyme immuno assay, QuickC6, in acute
Lyme neuroborreliosis (LNB) in endemic areas. Paired sera and cerebral spinal fluids (CSFs) from 60 patients with definite LNB, eight patients with possible LNB, 18 patients with conditions mimicking LNB and 42 persons with noninfectious neurological
disease were examined. The case definition of LNB was based on strict criteria during a prospective 4-month follow-up. The sensitivity of QuickC6 was 98% both in sera and CSFs, and the diagnostic specificity was 61% in sera and 88% in CSFs. QuickC6 is a sensitive, simple and cost-effective screening test in serum and CSF in diagnosis of acute LNB. Specificity needs further evaluation.