Cysteine-rich secretory protein 1 in seminal plasma: potential biomarker for the distinction between obstructive and nonobstructive azoospermia.

To investigate the presence of cysteine-rich secretory protein 1 (CRISP1) in seminal plasma as a means of distinguishing between obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). Seminal plasma from normospermic donors (n = 45) and azoospermic donors (n = 80) was examined to determine CRISP1 levels. Neutral alpha-glucosidase (NAG) enzymatic activity was measured for comparison with CRISP1 levels. Research unit of an academic medical center. Normospermic and azoospermic donors from the clinical andrology laboratory of the centre hospitalier universitaire de Québec and from Mount Sinai Hospital. Seminal CRISP1 measurement by Western blot analysis. Neutral alpha-glucosidase activity was evaluated by a photometric method. Seminal plasma CRISP1 levels, NAG activity, cutoff value, sensitivity, and specificity. All seminal plasma samples from normospermic and nonobstructive azoospermic donors were CRISP1 positive, whereas CRISP1 was absent or present at low levels in samples from patients with OA. A significant correlation between seminal CRISP1 levels and NAG activity was found in azoospermic semen samples. The cutoff point to distinguish between donors with NOA or OA was established at 0.655 (relative intensity). At this threshold, specificity was 85% and sensitivity was 92%. Seminal CRISP1 combined with NAG activity can potentially distinguish between OA and NOA.