Utility of serodiagnostics designed for use in the United States for detection of Lyme borreliosis acquired in Europe and vice versa.

Although two-tier testing is standard practice in both the United States and Europe for the serologic diagnosis of Lyme borreliosis (LB), the test kits generally differ. The purpose of this study was to determine if the testing used in the United States will detect LB acquired in Europe and vice versa. Testing was performed on a convenience sample of archived sera from 40 LB patients from Austria and 39 from the United States, using first- and second-tier test kits from both the United States and Europe. The sensitivity of four first-tier tests from Europe and two first-tier tests from the United States was similar. Thus, two-tier testing was compared to the C6 ELISA as the first-tier test, since it is licensed in both the United States and Europe. The sensitivity of C6 two-tier testing with US assays was 9/40 (22.5 % [95 % CI 10.8-38.5 %]) for detection of LB acquired in Europe, and just 20.0 % (95 % CI 2.5-55.6 %) in the ten European patients with neurologic involvement. These results differed significantly from the sensitivity of European C6 two-tier testing that was 70.0 % (95 % CI 53.5-83.4 %) overall (p < 0.001) and 90.0 % (95 % CI 55.5-99.7 %) for the European patients with neurologic manifestations specifically (p = 0.016). In contrast, the sensitivity of European and US C6 two-tier testing was similar for detection of LB acquired in the United States. Two-tier serologic testing with the US test kits may be unsatisfactory for detection of LB acquired in Europe. First-tier testing with an assay such as the C6 ELISA should be considered as a stand-alone diagnostic strategy in such cases.