Blocking Nonspecific Primer Amplification in Loop-Mediated Isothermal Amplification with TrueLAMP

Loop-mediated isothermal amplification (LAMP) is a rapid and equipment-minimal nucleic acid amplification method, but its broader adoption has been hindered by nonspecific primer amplification that generates false positives in no-template controls and sample reactions. We developed TrueLAMP, a polymerase formulation containing a proprietary inhibitory component that selectively blocks primer-driven amplification while preserving target-specific amplification. Using SARS-CoV-2 RNA and virions as model systems, TrueLAMP was evaluated across multiple independent primer sets with both semi-real-time colorimetric imaging in a convection oven and endpoint colorimetric detection in a water bath. TrueLAMP achieved a limit of detection of 250 RNA copies per reaction with 96.9 % sensitivity and 100 % specificity. By eliminating false positives without increasing assay complexity, TrueLAMP enhances confidence in colorimetric LAMP assays and preserves their hallmark simplicity, enabling robust molecular detection using unmodified, off-the-shelf equipment suitable for decentralized, point-of-care, and resource-limited settings.