Pharmacogenomics provides enormous potential for significantly improving the medication response and therapeutic outcomes in patients, but little clinical realization of that potential to date. One of the reasons for this is the lack of facile, rapid and cost-effective methods to perform the genotyping. State of the art facilities require enormous start-up funding, significant space, and multiple personnel. Many research-interested institutions do not have such a facility and so are limited in the ability to perform pharmacogenomics studies. Type 2 diabetes mellitus represents a significant burden to healthcare and is associated with high morbidity and mortality. Metformin, a common first line treatment for Type 2 diabetes, is processed by organic cation transporters (OCT). Previous study has shown that an inactivating mutation of OCT1, del420, has been linked to metformin response. Thus detection of this variant in patients may aid in their therapeutic drug management and enhance their treatment outcomes. We report here a facile, rapid and inexpensive method to detect this OCT1 del420 variant.