Polymorphisms associated with genes coding for a variety of drug-metabolizing enzymes （DMEs） and associated transport proteins can influence the drug metabolism rate of individuals, potentially affecting the efficacy of drug and the occurrence of adverse reactions. Single nucleotide polymorphisms （SNPs） are prevalent in all types of genetic variations. Reliable SNP genotyping provides excellent markers for detecting genetic polymolphisms, genetic disorders, and resistance of pathogen to drug, which are needed for the genetic diagnosis of disease and subtle genetic factors. With a large number of SNP genotyping studies being conducted, a lot of novel SNP identifying methods have been developed. Several SNP genotyping methods and techniques have been introduced for clinical test. These include TaqMan drug metabolism genotyping assays, pH-sensing semiconductor system, high-resolution melting curve analysis （HRM） of polymerase chain reaction （PCR） amplicons, novel multiplexed electrochemical biosensor with non-fouling surface, DNA hybridization detection using less than 10-nm gap silicon nanogap structure, tetra-primer ARMS-PCR method, acoustic detection of DNA conformation in genetic assays combined with PCR, microbeads-mass spectrometry （MEMS）-based approach, and liquid chromatography-electrospray ionization mass spectrometry. Personalized medicine has changed the conventional ways of using drugs according to experiences. It focuses on making the individualized pattern for each individual based on their own characteristics. Lots of researchers are using the analysis of clinical samples to explain the relationship between the drug adverse reactions and genetic polymorphisms. But it takes a long time from collecting the blood samples for DNA extraction and genotyping to getting results on the side effect of drug through clinical study. Therefore, it is desirable to develop improved in vitro methods to study the drug metabolizing-enzymes and transport protein genetic polymorphisms.
