RESUMO
BACKGROUND: The -13910 C/T single nucleotide polymorphism located within the MCM6 gene, an enhancer region located upstream of the lactase-phlorizin hydrolase gene, is associated with lactase persistence/non-persistence traits among the Caucasian population. The performance of a new point-of-care CE-IVD (In Vitro Diagnostic) marked isothermal lab-on-phone lactose intolerance assay, using crude samples, was assessed in comparison with Sanger sequencing using purified DNA, as reference method. METHODS: The study was conducted following a non-probability sampling using direct buccal swab (n = 63) and capillary blood (n = 43) clinical samples from a total of 63 volunteers. A 3 × 3 confusion matrix/contingency table was used to evaluate the performance of the isothermal lab-on-phone lactose intolerance assay. RESULTS: The isothermal lab-on-phone lactose intolerance assay successfully detected the -13910 C/T variant with a limit of detection of 5 cells/assay and demonstrated an overall accuracy of 98.41% (95% CI, 91.47%-99.96%) for buccal swab samples and 100% (95% CI, 91.19%-100%) for capillary blood, taking just 90 min from sample to result, with only 2 min hands-on. CONCLUSIONS: The lab-on-phone pocket-sized assay displayed good performance when using direct buccal swab and capillary blood samples, enabling a low-cost, real-time, and accurate genotyping of the -13910 C/T region for the rapid diagnosis of primary lactose intolerance at point-of-care, which enables a prompt implementation of appropriate diet habits and/or intolerance therapies. To our knowledge, this is the first point-of-care genetic test for lactose intolerance to be made available on the market.
