The First Point-Of-Care Test For Lactose Intolerance

In a recent study published in The Journal of Applied Laboratory Medicine, researchers evaluated the performance of a compact diagnostic assay that can accurately and rapidly diagnose lactose intolerance using capillary blood and buccal swab samples, News Medical Net, reported.

A decrease or absence in the synthesis and activity of the lactase-phlorizin hydrolase enzyme (LHP), commonly known as lactase, results in lactose intolerance. Lactase, or LPH, is essential for breaking down lactose, and the expression of LPH is genetically programmed to be downregulated during adulthood.

The ancestral state in humans for the processing of lactose is the lactase non-persistence (LNP) phenotype, also know and adult-type hypolactasia, and individuals who have retained this ancestral phenotype experience bloating, intestinal cramps, flatulence, and diarrhea upon consuming lactose.

However, while most adults can tolerate small quantities of lactose without much discomfort, some can consume lactose without any symptoms of lactose intolerance.

The minichromosome maintenance complex component 6 (MCM6), an upstream transcriptional enhancer, regulates the expression of the LCT gene that codes for lactase. Single nucleotide polymorphisms (SNPs) or a single base-pair mutation in the MCM6 region have resulted in an alternate phenotype called lactose persistence or LP, which enables individuals to digest lactose throughout adulthood.

A quick and efficient method to diagnose lactose intolerance based on these two phenotypes would help lactose-intolerant individuals formulate or modify dietary strategies.

The entire process, from sample collection to obtaining the results, was completed in 90 minutes, with hands-on time being just 2 minutes. The detection limit obtained for the STAB VIDA Lda assay is comparable to the existing gold-standard methods of Sanger sequencing and PCR-based assays.

The study is titled: “A Genetic Lab-on Phone Test for Point-of-Care Diagnostic of Lactose Intolerant near Patient and in less than 90 minutes” was posted on The Journal of Applied Laboratory Medicine. From the study:

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-proballity sampling using direct buccal swab (n= 63) and capillary blood (n = 43) clinical samples from a total of 63 volunteers. A 3 x 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% Cl, 91.19% – 100%) for capillary blood, taking just 90 min from sample to result, with only 2 min hands-on.

Conclusions: The isothermal lab-on-phone lactose intolerance assay has been demonstrated to be a reliable pocket-sized portable system for point-of care diagnosis that can be easily used in the field, over-the-counter, or at-home testing for primary lactose intolerance diagnostic. The assay provides rapid real-time results to identify the genotype of a patient with suspected lactose intolerance, which can be a very important factor for the implementation of appropriate therapy an diet adjustments. To our knowledge, this is the first point-of-care genetic test for lactose intolerance available on the market.

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