实时荧光PCR和六胺银染色对肺孢子菌肺炎诊断价值的分析评价

Evaluation of Real-time PCR and Gomori-Methenamine Silver Stain for Diagnosing of Pneumocystis Pneumonia

目的比较实时荧光PCR和六胺银染色对肺孢子菌肺炎(PCP)的诊断价值。方法收集2014年1～12月北京协和医院疑似PCP患者非重复送检标本共2 525例,其中2 492例标本用六胺银染色法对肺孢子菌孢囊进行检测,33例标本用实时荧光PCR法对PCP-DNA进行检测,429份标本同时用六胺银染色法和实时荧光PCR法进行检测,以临床诊断为标准,分析两种方法的阳性率、敏感度、特异度、阳性预测值和阴性预测值。结果六胺银染色法的阳性率为1.2%(30/2 492),其中痰、气管插管支气管吸取物和肺泡灌洗液的阳性率分别为0.70%(13/1 845),4.00%(10/250)和2.72%(7/257)。实时荧光PCR法的阳性率为34.20%(158/462),痰和肺泡灌洗液的阳性率分别为30.61%(105/343)和44.54%(53/119)。六胺银染色法和实时荧光PCR法的敏感度13.97%vs 72.07%(χ~2=68.625,P<0.01),特异度100%vs94.24%(χ~2=4.296,P<0.05),阳性预测值100%vs 92.14%(χ~2=6.380,P<0.01),阴性预测值55.36%vs 78.26%(χ~2=11.873,P<0.01),差异均具有统计学意义。结论实时荧光PCR敏感度高,相对干扰因素少,临床诊断价值高,但标本送检率明显低于六胺银染色,建议临床提高其送检率,提高PCP的早期诊断。

Objective To compare real-time PCR and gomori methenamine silver stain in the diagnosis of pneumocystis peumonia （PCP）. Methods 2 525 unrepeated specimens from suspected PCP patient admitted in Peaking Union Medical College Hospital were collected in 2014.2 492 samples were detected by gomori-methenamine silver stain,33 samples were detected by real-time PCR,and 429 samples were detected by both methods at the meanwhile. With clinical diagnosis as reference standard,the sensitivity,specificity, positive predictive value and negative predictive value of the two methods were analy sised. Results Positive rate of gomori-methenamine silver stain was 1.2% （30/2 492）. The first three specimen types were sputum, tracheal intubation suction and bronchoalveolar lavage fluid, the positive rate was 0.70 % （13/1 845）, 4.00 % （ 10/ 250） and 2.72% （7/257） respectively. Positive rate of realtime PCR was 34.20% （158/462） ,and the positive rate of spu turn and bronchoalveolar lavage fluid was 30.61% （105/343） and 44.54% （53/119） respectively. The sensitivity were 13.97% vs 72.07% ,specificity were 100% vs 94. 24% ,positive predictive value were 100% vs 92. 14% and negative predictive value were 55.36% vs 78.26% for gomori-methenamine silver stain and real time PCR respectively. All of which were statistically significant analysed by Z2 test for paired data. The Z2 value and P alue were Х^2 = 68. 625,P〈0.01;Zz = 4.296,P〈0.05;Z2 6. 380,P〈0. 01 and Х^2=11.873,P%0.01.Conclusion The real-time PCR had higher sensitivity,fe wer interference factors and more clinical diagnostic value,so clinicians should make more use of real-time PCR to diagnose PCP earlier.