FIGURE 1.

The mechanism and colorimetric results of an MTT test strip. (a) The mechanism of the sperm and MTT interaction. There is an abundance of mitochondria in the middle portion of the sperm cell, where succinate dehydrogenase (SDH) located on the mitochondria transforms yellow‐colored MTT into purple‐colored formazan. (b) The color of the MTT test strip before and after testing the semen sample. The colorimetric result is homogenously distributed over the testing zone of the MTT test strip and the result can be easily interpreted by visual observation or with a smartphone‐based recording and analytical system. MTT, 3‐(4,5‐Dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide