The limit of detection of a Phytophthora agathidicida LAMP assay is higher under alternative laboratory conditions.

Surveillance of Phytophthora agathidicida , the causal agent of kauri dieback, has included soil baiting followed by loop-mediated isothermal amplification (LAMP)-based detection. This approved assay was reported to detect 1 fg of DNA using OptiGene Isothermal Master Mix on a BioRanger instrument. We evaluated its analytical robustness using the same master mix on an alternative platform (QuantStudio 3), and separately tested an alternative NEB master mix. Both assays yielded a reliable detection limit of 1,000 fg, with variable detection at 100 fg and none below. Diagnostic laboratories should verify assay performance under their operational conditions prior to implementation.