诊断PADAM血清游离睾酮测定方法和界限值的研究

目的比较推算法和酶免法测定血清游离睾酮（FT）的结果,探寻FT诊断中老年男子部分性雄激素缺乏综合征（PADAM）的界限值,并评估游离睾酮指数（FTI）。方法收集129例45岁以上健康男性的血清标本,酶标免疫法测定游离睾酮（aFT）,同时测定总睾酮（T）和性激素结合球蛋白（SHBG）并代入Vermeulen公式推算游离睾酮（cFT）,对两种方法的FT值进行比较。其中60例,根据视听性刺激（AVSS）时阴茎勃起监测结果分组,计算勃起正常组cFT的参考范围。以此值为依据,对FTI进行有效性检验。结果1.cFT和FTI与年龄相关性较好,而cFT与aFT值相差有统计学意义。2.cFT：勃起正常组0.37（0.20～0.52）nmol/L,异常组0.25（0.12～0.40）nmol/L。3.FTI：cFT异常组0.15,正常组0.51。FTI敏感性97.78%,特异性58.33%。结论推算法测定血清FT较酶免法科学、准确。0.20nmol/L是cFT诊断PADAM的界限值。FTI可作为PADAM病人治疗反应的随访。

Validation of serum free testosterone level in diagnosis of PADAM

Objective To compare serum free testosterone (FT) level obtained by calculation method or direct measurement, define a threshold value of FT for the diagnosis of partial androgen deficiency in the aging male (PADAM) and critically evaluate free testosterone index (FTI) with this criterion. Methods FT levels obtained by direct enzyme linked immunosorbent assay (aFT) and by calculation with the Vermeulen's formula (cFT) after determining the total testosterone (T)and sex-hormone-binding globulin (SHBG) were compared in 129 healthy males over 45 years. Of them, 60 men were divided into normal or abnormal groups according to the results of the erection function in audio-visual sexual stimulation (AVSS) test,where the reference range of cFT natural level was calculated, and the validity of FTI with the threshold value was evaluated extensively. Results 1. Both cFT and FTI correlated well with age, while cFT values varied considerably with aFT; 2. The reference value of cFT in normal and abnormal erection groups was 0.37(0.20～0.52 percentile) nmol/L and 0.25(0.12～0.40percentile) nmol/L respectively; 3. Using the threshold value of cFT 0.20nmol/L as the criterion, FTI value was 0.15 in abnormal erection group and 0.51in normal group. The seusitivity of FTI was 97.78% and the specificity of FTI was 58.33%. Conclusions cFT seems to be more scientific and accurate than aFT. This study supports the use of cFT with the threshold value 0.20nmol/L as an acceptable parameter for diagnosing PADAM. FTI could be used as an index for after-treatment follow-up of patients with hypogonadism.