ABSTRACT
<p><b>OBJECTIVE</b>To observe the changes of serum free testosterone (FT) and testosterone secreting index (TSI) in ED patients, and to assess the contribution of these two indexes to the diagnosis of ED caused by endocrine factors.</p><p><b>METHODS</b>We studied 120 ED patients and 30 healthy men undergoing pre-marital medical check-up in Jiangsu Province Hospital of TCM by analyzing the scores on erectile function and desire domain in IIEF, testing the serum total testosterone, luteinizing hormone by chemiluminescent enzyme immunoassay (CLIA), measuring free testosterone by radioimmunoassay( RIA), and calculating TSI.</p><p><b>RESULTS</b>Of the 120 ED patients, 5% and 1538% were below the reference norm of TT and FT values respectively. TT, FT and TSI decreased with age, with statistical with FT and TSI, but not with TT. FT and TSI statistically declined with lower IIEF score on ED domain, but this was not the case with TT. There were no significant differences in TI, FT and TSI among different sexual desire groups the ED patients.</p><p><b>CONCLUSION</b>FT is much more valuable than TF in the diagnosis of ED with hypogonadism. Both FT and TSI are important parameters in assessing the severity of ED.</p>