Interlaboratory Concordance of a Multiplex ELISA for Lyme and Lyme-like Illness Using Australian Samples and Commercial Reference Panels: A Proof-of-Concept Study

Tick bites acquired in the northern or southern hemisphere can transmit microbes that may cause illness. The most prevalent infection is Lyme borreliosis (LB), with all proven cases to date having been acquired in the northern hemisphere. The existence of endemic LB in Australia has not been proven explicitly, and there is uncertainty concerning the cause of "Lyme-like" disease (LLD) in Australia. As many tick-borne diseases (TBDs) are diagnosed by serology, validated assays for use in both the northern and southern hemispheres are required. Using a multiplex enzyme-linked immunosorbent assay (TICKPLEX^®), two independent laboratories tested a total of 53 well-characterized reference sera that consisted of 33 samples from northern hemisphere patients with confirmed tick-borne disease (TBD) and 20 randomly selected sera from Australian patients with suspected TBDs, presenting with or without LLD. Antibody responses to multiple microbial antigens from causative agents of TBDs were found. High concordance between laboratories was demonstrated on this small set of samples. The results obtained provide the basis for further evaluation of TICKPLEX^® on a larger number of samples from Australian patients with suspected TBDs. These findings should be considered preliminary, providing proof-of-concept evidence that warrants validation in larger, clinically diverse cohorts.