Determination of limit of detection (LOD) for loop-mediated isothermal amplification (LAMP) of human cytomegalovirus (hCMV) DNA

The importance of cytomegalovirus in clinical practice remains and samples are monitored for CMV DNA titers to predict the development of disease. LAMP assays have gained increasing interest in the diagnosis of many pathogens since they do not require thermocycling, reduce the complexity of the required instrumentation as well as providing sensitivity and rapidity. So far, very few studies on CMV detection by LAMP have been reported in the literature and therefore the performance of LAMP CMV assays needs to be further characterized. In a set-up for biometrological evaluation of the suitability of the LAMP assay for CMV diagnosis, a LAMP assay was performed on a total of 192 samples with 24 replicates of 8 different hCMV DNA concentrations. The LOD was calculated as 39.09 copy/reaction (25.33 copy/reaction to 65.84 copy/reaction) with 95 % confidence, representing a range that is suitable for qualitative detection. Furthermore, the lower limit of quantification was estimated at approximately 100 copy/reaction. The LOD and LLOQ values obtained in this first study to assess the biometrological relevance of LAMP CMV tests are consistent when compared to studies published before. However further study under different conditions is needed for the use of LAMP tests in clinical applications.