​The Sequenom MassARRAY system was created based on the technology of MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectrometry. Given the system has flexibility of experimental design (design array by Sequenom software) and can generate accurate and most reproducible results, genotyping is a popular and effective way to screen for SNPs and structural variations. It is also appropriate and convenient for the detection of drug resistance gene and viral genotyping clinically.