NGF and varicocele: NGF was significantly higher in men with varicocele or UGI compared with fertile men (2049.0 ± 750.8 pg/mL and 1673.0 ± 457.6 pg/mL vs. 763.3 ± 279.4 pg/mL; p = 0.015 and p = 0.02, respectively (image on the left).