LDH-x in azoospermia: a new diagnostic alternative to vasography and testicular biopsy

Activities of different isozymes of lactate dehydrogenase were studied in semen samples from fertile, and different groups of infertile men. No isozyme except the sperm specific LDH-x or C4 showed any difference in activity with changes in sperm density. Activity of LDH-x exhibited a trend positive to changes in sperm density and became absent in obstructive and vasectomized azoospermia. Among other types of azoospermia, the activity became very high in maturation arrest but very low in patients with testicular biopsy showing germ cell aplasia, such as in SCOS and ghostlike tubules. Diagnostic usefulness of the estimation of LDH-x activity in semen is discussed.