Introduction: Fertility potential in adolescent boys with varicocele is best assessed with semen analysis (SA), however a SA can be difficult to obtain in some patients. Surrogates for abnormal SA, such as FSH and Inhibin B, have been investigated to potentially circumvent the barriers related to boys obtaining SA. Recent reports note the Inhibin B/FSH ratio may have good predictive value of testis health in adult varicoceles and infantile undescended testes. We hypothesize that Inhibin B/FSH ratio is a better predictor than FSH or Inhibin B alone in identifying abnormal SA in adolescent boys with left varicocele. Methods: We queried our IRB-approved varicocele registry to identify Tanner V boys with palpable varicocele, SA and serum hormonal labs (FSH, Inhibin B) within 12 months of the SA. Abnormal SA was defined as TMC <9 million. ROC analysis was used to determine how well hormone levels (FSH, Inhibin B and Inhibin B/FSH ratio) could predict abnormal SA. Optimal cutoffs were calculated using the Youden index (J). Results: Of 2158 patients in our registry, 192 Tanner V boys with palpable varicocele, SA, and hormone labs were included. Overall mean age was 17.2 years. Significant differences were noted in mean Inhibin B (226 vs 173; p=0.001), median FSH (3.3 vs 4.9; p=0.001), median TMC (37 vs 3.1; p=0.001), and median Inhibin B/FSH ratio (69 vs 32; p=0.001) between boys with normal and abnormal SA, respectively [Table 1]. ROC curves were generated to determine optimal cutoffs for FSH, Inhibin B, and Inhibin B/FSH ratio to predict abnormal SA [Figure 1]. Inhibin B/FSH ratio showed the highest AUC (0.66, sensitivity 71% specificity 61%.) overall at a cutoff of 53. Conclusions: In our analysis of adolescent patients with palpable varicocele, Inhibin B/FSH ratio does appear to be a better predictor of abnormal SA (TMC <9mil) than FSH or Inhibin B alone. Despite there being a clear correlation between all three markers and abnormal SA, the mediocre AUC’s of 0.65 – 0.66 for each respective cutoff, make clinical decision making solely on markers difficult. SOURCE OF Funding: -
