Evaluation of Real-time PCR and Gomori-Methenamine Silver Stain for Diagnosing of Pneumocystis Pneumonia / 现代检验医学杂志

ABSTRACT

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 analysised.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 sputum 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 x2 test for paired data.The x2 value and P alue were x2 =68.625,P＜0.01;x2 =4.296,P＜0.05;x2 =6.380,P＜0.01 and x2 =11.873,P＜0.01.Conclusion The real-time PCR had higher sensitivity,fewer interference factors and more clinical diagnostic value,so clinicians should make more use of real-time PCR to diagnose PCP earlier.