梅毒螺旋体特异性抗体检测灰区范围分析

Analysis of grey area of Treponema pallidum specific antibody detection

目的探讨化学发光法检测梅毒螺旋体特异性抗体的灰区范围,提高梅毒实验室检测的有效性和准确性。方法收集解放军总医院第五医学中心2016年2月~2018年5月采用化学发光法检测梅毒螺旋体特异性抗体,样品吸光度与临界值的比值(S/CO)为1~9(拟定灰区)的患者,以梅毒实验室逆向检测流程及免疫印迹法结果为金标准,评价化学发光法检测灰区的假阳性率。结果采用化学发光法检测梅毒螺旋体抗体患者25 190例,灰区患者462例(1.83%)。其中S/CO值1~3患者234例,假阳性率为0.74%;S/CO值>3~6患者109例,假阳性率0.27%;S/CO值>6~9患者119例,假阳性率0.12%,三组比较差异有统计学意义(P <0.05)。选取假阳性率较低的S/CO值>6~9组患者比较,S/CO值>6~7时假阳性率为0.072%,S/CO值>7~8时假阳性率为0.024%,S/CO值>8~9时假阳性率为0.020%,三组比较差异有统计学意义(P <0.05)。结论化学发光法检测梅毒螺旋体特异性抗体,在拟定灰区范围内,假阳性率随S/CO值升高呈现降低趋势。灰区范围宜设定为S/CO值1~7。

Objective To investigate the grey area of Treponema pallidum specific antibody detected by chemiluminescent immunoassay, and improve the validity and accuracy of syphilis laboratory diagnosis. Methods The patients with cut-off (S/CO) value 1 to 9 (assumed grey area) of Treponema pallidum specific antibody detected by chemiluminescent immunoassay from February 2016 to May 2018 were collected from the Fifth Medical Center in General Hospital of PLA. The false positive rate of chemiluminescent immunoassay in grey area was evaluated by using the methods of reverse detection process of syphilis laboratory and the results of immunoblotting as gold standard. Results A total of 25 190 cases were detected by chemiluminescent immunoassay, and 462 cases (1.83%) were observed within grey area. The false positive rate was 0.74% in 234 cases with S/CO values ranging from 1 to 3, 0.27% in 109 patients with S/CO values ranging from greater than 3 to 6, and 0.12% in 119 patients with S/CO values ranging from greater than 6 to 9. There was a significant difference among three groups (P < 0.05). Comparison of S/CO values in greater than 6 to 9 patients with lower false positive rate, the false positive rate of S/CO value greater than 6 to 7 was 0.072%, the false positive rate of S/CO value greater than 7 to 8 was 0.024%, the false positive rate of S/CO value greater than 8 to 9 was 0.020%, and the difference between three groups was statistically significant (P < 0.05). Conclusion In the assumed grey area, when the specific antibody of Treponema pallidum is detected by chemiluminescent immunoassay, the false positive rate showes a decreasing trend with the increase of S/CO value. The gray area should be set to S/CO value of 1 to 7.