Carlson G D, Calvanese C B, Childs S J
DIANON Systems, Stratford, Connecticut 06615, USA.
Urology. 1998 Sep;52(3):450-4. doi: 10.1016/s0090-4295(98)00214-3.
The ability of percent free prostate-specific antigen (PSA) to distinguish benign from malignant prostate disease has been established within the 4.0 to 20.0 ng/mL total PSA range, but its utility within the less than 4.0 ng/mL total PSA range has not been clearly defined. We undertook this study to determine the lower limit for the percent free PSA reflex range.
Four hundred seventy-nine men (mean age [+/-SD] 63.2 +/- 9.68 years) met the following criteria: (1) a measurable total serum PSA level of 4.0 ng/mL or less (mean 2.64 +/- 0.050); (2) concurrently measured free PSA and percent free PSA calculated (mean 19.3% +/- 0.59%); (3) a sextant biopsy diagnosed benign (B) (n = 376) or malignant (M) (n = 103), at one institution, within 90 days of serum collection; and (4) no prior history of prostate cancer. We defined the lower limit to be the lowest total PSA value at which (1) percent free PSA distributions differed between benign and malignant cases; and (2) percent free PSA could predict malignant disease. We compared age, total PSA, and percent free PSA differences with the Mann-Whitney U test and analysis of variance, and used univariate logistic regression to determine each variable's predictive value. Other statistical analysis was performed with contingency tables, Fisher's exact test, and linear regression.
The lowest total PSA value at which percent free PSA both differed between benign and malignant cases and predicted prostate cancer was 4.0 ng/mL.
The lower limit for the percent free PSA reflex range should be 4.0 ng/mL.
游离前列腺特异性抗原（PSA）百分比在总PSA浓度范围为4.0至20.0 ng/mL时，已被证实具有区分前列腺良性疾病与恶性疾病的能力，但其在总PSA浓度低于4.0 ng/mL时的效用尚未明确界定。我们开展这项研究以确定游离PSA反射范围的下限。
479名男性（平均年龄[±标准差]63.2±9.68岁）符合以下标准：（1）可测量的血清总PSA水平为4.0 ng/mL或更低（平均2.64±0.050）；（2）同时检测游离PSA并计算游离PSA百分比（平均19.3%±0.59%）；（3）在一家机构，于血清采集后90天内进行的六分区活检诊断为良性（B）（n = 376）或恶性（M）（n = 103）；（4）无前列腺癌既往史。我们将下限定义为满足以下条件的最低总PSA值：（1）良性和恶性病例的游离PSA百分比分布存在差异；（2）游离PSA百分比可预测恶性疾病。我们采用Mann-Whitney U检验和方差分析比较年龄、总PSA和游离PSA百分比差异，并使用单因素逻辑回归确定每个变量的预测价值。其他统计分析采用列联表、Fisher精确检验和线性回归。
游离PSA百分比在良性和恶性病例之间存在差异且可预测前列腺癌的最低总PSA值为4.0 ng/mL。
游离PSA反射范围的下限应为4.0 ng/mL。
