Performance of United States Serologic Assays in the Diagnosis of Lyme Borreliosis Acquired in Europe

Background. Physicians in the United States sometimes need to evaluate a patient for suspected Lyme borreliosis (LB) who may have acquired the infection in Europe. Using serum samples from European LB patients, we compared the performance of European and US serodiagnostic tests, including newer-generation assays containing Vmp-like sequence, expressed or its C6 peptide. Methods. The sensitivity of each assay was determined using 64 serum samples from LB patients with early or late disease manifestations who acquired the infection in Europe. Specificity was measured using 100 sera from healthy subjects from a nonendemic area. Results. For the detection of European-acquired infection, conventional 2-tiered testing (enzyme-linked immunosorbent assay [ ELISA] followed by immunoblotting) using US assays had an overall sensitivity and specificity of 52% and 100%, compared with 81% (P = .0007) and 99% (P = 1.00) using analogous European tests. The sensitivity of a US C6 ELISA used as a stand-alone test (88% overall) was statistically comparable to that of conventional 2-tiered testing using European tests (P = .47) and was 100% specific. Similarly, an alternative 2-tiered algorithm using a standard US ELISA followed by a C6 ELISA was comparably sensitive (84% overall) compared with conventional 2-tiered testing using European assays (P = .82), and specificity remained 100%. Conclusions. European assays outperformed analogous US assays in a conventional 2-tiered testing algorithm. However, a C6 ELISA used as a stand-alone test or in the second tier of a 2-tiered algorithm performed comparably to conventional 2-tiered testing using European assays, and can be used for evaluation of any patient, regardless of travel history.