Seminal plasma characteristics as indicators of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in men with obstructive azoospermia

Objective: To determine the prognostic value of seminal plasma volume, pH, fructose, and α-glucosidase for the detection of cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. Design: Retrospective data analysis. Setting: University infertility clinic (referral center). Patient(s): Fifty-nine men with obstructive azoospermia. Intervention(s): Semen analysis including seminal plasma volume, pH, fructose, α-glucosidase, molecular genetic diagnosis of CFTR mutations and FSH measurement. Main Outcome Measure(s): Sensitivity and specificity of seminal plasma markers for the detection of CFTR mutations. Result(s): A CFTR mutation was detected in 26 of 59 patients with obstructive azoospermia. Patients carrying a mutation had significantly lower seminal plasma volume (mean ± SEM: 1.5 ± 1.4 mL vs. 2.8 ± 2.2 mL), lower pH levels (25th percentile, median, 75th percentile: 6.5, 6.8, 7.5 vs. 7.7, 7.9, 7.9) and lower fructose content (1.0, 1.1, 3.7 vs. 5.8, 20.0, 83.0 μmol/ejaculate) than those without mutations. Diagnostic efficacy for detection of mutations was best (pH 81.4%, fructose 81.8%) at a cutoff level for pH of 7.4 and fructose of 2 μmol/ejaculate. Conclusion(s): Seminal plasma markers provide an effective, noninvasive method to predict CFTR mutations in men with obstructive azoospermia.