Suppressing Primer-Driven Nonspecific Amplification in LAMP Using TrueLAMP

Abstract

Loop-mediated isothermal amplification (LAMP) enables rapid nucleic acid detection but is vulnerable to primer-driven nonspecific amplification that can produce false-positive results. We developed TrueLAMP, a colorimetric LAMP formulation containing an inhibitor that suppresses nonspecific amplification while preserving target-dependent amplification. All 65 no-template controls across these studies remained negative, corresponding to 100% observed specificity. Using SARS-CoV-2 as a model and the Lamb primer set as a representative benchmark, TrueLAMP achieved a limit of detection of 250 copies per reaction with 95% detection probability. Endpoint color remained stable during extended incubation, reducing the need for time-critical readout. TrueLAMP was compatible with readily available heating devices, including a convection oven, water bath, and temperature-controlled smart mug. Independent evaluations in two external laboratories using additional primer-template systems, including DNA targets, further supported suppression of nonspecific amplification and sequence-dependent target detection. Together, these findings support TrueLAMP as a practical approach for improving the reliability of LAMP detection while retaining a simple isothermal workflow.