The ability of the markers alpha-glucosidase, carnitine, and glycerylphosphorylcholine to indicate epididymal obstruction was studied. alpha-Glucosidase was found to be the best discriminant, with 93.4% correct classifications. The possible interrelationship between alpha-glucosidase activity, sperm ATP, and epididymal function was then studied. alpha-Glucosidase correlated positively with the percentage of motile sperm (p = 0.0212) and with the percentage of sperm with good forward progression (p = 0.0374), but correlated negatively with the sperm ATP (p < 0.0500). It was concluded that lower ATP and higher alpha-Glucosidase may be markers of efficient epididymal function. The possible epididymal origin of detached ciliary tufts (DCTs) was studied by determining ATP and alpha-glucosidase activity in patients with DCTs. The mean ATP in patients with DCTs was significantly higher (p = 0.009), but the alpha-glucosidase activity significantly lower (p = 0.0412) than in the control group. These results seem to support the epididymal origin of DCTs.