不同方法检测流行性感冒样病例鼻咽和口咽拭子标本诊断甲型流行性感冒的评价

Evaluation of nucleic acid amplification assay and rapid antigen assay of nasopharynx swabs and oropharynx swabs from flu-like patients in diagnosis of flu A

目的．用两种不同方法检测流行性感冒（流感）样病例鼻咽拭子和口咽拭子标本，比较其检测甲型流感的结果。方法选择2009年9月至10月间在佑安医院门诊就诊的170例有流感样症状的病例，同时采集其鼻咽拭子和口咽拭子标本。用实时荧光定量RT—PCR法和快速抗原法同时检测甲型流感病毒核酸或甲型流感病毒抗原。数据行卡方检验。结果鼻咽拭子标本用核酸方法检测甲型流感病毒的阳性率为74．1％（126／170），抗原方法检测的阳性率为65．9％（112／170）（X^2=2．75，P〉0．05）；而口咽拭子标本核酸方法检测甲型流感病毒的阳性率为62．9％（107／170），抗原方法检测的阳性率为38．8％（66／170）（X^2=19．78，P〈0．01）。核酸方法检测鼻咽拭子标本的阳性率高于口咽拭子（X^2=4．90，P〈0．05），且抗原方法检测鼻咽拭子标本的阳性率也高于口咽拭子（X^2=24．95，P〈0．01）。以鼻咽拭子核酸方法检测甲型流感为参照，口咽拭子核酸方法、口咽拭子抗原方法、鼻咽拭子抗原方法检测的敏感度分别是81．7％、50．0％和94．8％；特异度分别是90．9％、93．2％和95．5％；阳性预测值分别为96．3％、95．5％和98．2％；阴性预测值分别为63．5％、39．4％和72．4％；Kappa系数分别是0．64、0．30和0．75；总符合率分别为84．1％、61．2％和89．4％。结论鼻咽拭子标本检测甲型流感敏感度高于相应的口咽拭子，且核酸方法检测甲型流感的敏感度高于抗原方法。

Objective To compare the detection of flu A by nucleic acid amplification assay and rapid antigen assay in nasopharynx swabs and oropharynx swabs of flu-like patients. Methods A total of 170 flu-like patients were recruited in out-patient of Youan Hospital from September to October in 2009. Both nasopharynx swabs and oropharynx swabs were collected. Flu A virus was detected by both real-time reverse transcriptation polymerase chain reaction （RT-PCR） and rapid antigen assay. The data were analyzed by chi square test. Results For nasopharynx swabs, the positive rate of nucleic acid amplification assay was 74.1% （126/170）, while that of rapid antigen assay was 65.9% （112/170） （X2=2.75, P〉0.05）. However, for oropharynx swabs, the positive rate of nucleic acid amplification assay was much higher than that of rapid antigen assay （62.9% vs 38.8%） （X^2=19.78, P〈0.01）. Moreover, for nucleic acid amplification assay, the positive rate of nasopharynx swabs were higher than that of oropharynx swabs （X^2 =4. 90, P〈0. 05）. For rapid antigen assay, the positive rate of nasopharynx swabs was also higher than that of oropharynx swabs （X^2 = 24.95, P〈0.01）. Based on the outcome of flu A detected with nasopharynx swabs by the nucleic acid amplification assay, the sensitivities of oropharynx swabs by nucleic acid amplification assay, oropharynx swabs by rapid antigen assay, nasopharynx swabs by rapid antigen assay were 81.7%, 50.0% and 94.8%, respectively; the specificities were 90.9%, 93.2% and 95.5%, respectively; the positive predictive values were 96. 3%, 95. 5% and 98. 2%, respectively; the negative predictive values were 63.5%, 39.4% and 72.4%, respectively; Kappa coefficients were 0.64, 0.30 and 0.75, respectively; the total coincidences were 84.1%, 61.2% and 89.4%, respectively. Conclusions The detection of flu A with nasopharynx swabs is more sensitive than oropharynx swabs, and nucleic acid amplification assay is more sensitive than rapid antigen assay.