Comment; Polymerase Chain Reaction assay looks at the DNA directly instead of host antibodies to a pathogen. A test that can look at various tick-borne pathogens simultaneously–via DNA instead of antibodies, should help tremendously with accurate diagnosis to guide therapy.

Salika M. Shakir, Christopher R. Mansfield, Elizabeth D. Hays, Marc Roger Couturier, David R. HillyardDOI: 10.1128/JCM.01655-19


The incidence of tick-borne infections in the United States has risen significantly in the past decade. Ticks can transmit a variety of pathogens including bacteria, protozoan, and viruses that can cause serious illnesses. Therefore, the use of rapid, sensitive, and specific multiplex tests is important to identify the pathogen(s) in the acute phase and determine appropriate treatment to minimize the severity of the disease. The purpose of this study was to evaluate ChromaCode’s Research Use Only (RUO) nine target High-Definition PCR (HDPCR™) Tick-Borne Pathogen (TBP) panel using 379 retrospective, remnant whole blood and synovial fluid specimens previously submitted to ARUP laboratories and tested by clinically validated real-time PCR assays for Ehrlichia spp., Anaplasma phagocytophilumBabesia spp., or Lyme Borrelia spp. Performance characteristics evaluated included positive percent agreement (PPA) and negative percent agreement (NPA) with the ARUP laboratory developed tests (LDTs). All tested targets had an initial PPA greater than 97.0% except E. ewingii (88.9%). NPA for all targets was between 98.8% – 100%. The TBP panel detected three co-infections, two of B. microti and A. phagocytophilum, and one of B. microti and E. chaffeensis, which were confirmed by the LDTs. There were 16 samples with discordant results compared to the LDTs, five of which were resolved by repeat testing on the TBP Panel and bi-directional sequencing. Following discrepant resolution, the final PPA and NPA for the TBP panel was 97.7% (95% CI 95.2% – 99.0%) and 99.6% (95% CI 99.3% – 99.8%), respectively, with an overall agreement of 99.5% (95% CI 99.2% -99.7%) with the LDTs.

Dr. Raymond Oenbrink