Fig. 2. (A) Trak Male Fertility Testing system components and operation. The system contents include a reusable engine, single-use test cartridges (Props), fluid transfer device, liquefaction cups. Photo shows a prop placed on the engine. To operate the system, the user collects a semen sample in an enzyme-coated collection cup that promotes liquefaction. Then, the user transfers 0.25 mL of semen to the Prop inlet chamber, attaches the Prop to the engine, and closes the lid to initiate the spin sequence, which runs for 6 minutes at 7,000 rpm. When the spin sequence is complete, the sperm cells form a visible, measurable white column that's proportional to the concentration of sperm. (B) Test results of samples with low (<15 million/mL), moderate (15–55 million/mL), and optimal (>55 million/mL) sperm concentrations.