Reliability of a Newly-Developed Immunochromatography Diagnostic Kit for Pandemic Influenza A/H1N1pdm Virus: Implications for Drug Administration

BackgroundFor the diagnosis of seasonal influenza, clinicians rely on point-of-care testing (POCT) using commercially available kits developed against seasonal influenza viruses. However, POCT has not yet been established for the diagnosis of pandemic influenza A virus (H1N1pdm) infection due to the low sensitivity of the existing kits for H1N1pdm. Methodology/Principal FindingsAn immunochromatography (IC) test kit was developed based on a monoclonal antibody against H1N1pdm, which does not cross-react with seasonal influenza A or B viruses. The efficacy of this kit (PDM-IC kit) for the diagnosis of H1N1pdm infection was compared with that of an existing kit for the detection of seasonal influenza viruses (SEA-IC kit). Nasal swabs (n = 542) were obtained from patients with flu-like syndrome at 13 clinics in Osaka, Japan during the winter of 2010/2011. Among the 542 samples, randomly selected 332 were further evaluated for viral presence by reverse transcriptase polymerase chain reaction (RT-PCR). The PDM-IC kit versus the SEA-IC kit showed higher sensitivity to and specificity for H1N1pdm, despite several inconsistencies between the two kits or between the kits and RT-PCR. Consequently, greater numbers of false-negative and false-positive cases were documented when the SEA-IC kit was employed. Significant correlation coefficients for sensitivity, specificity, and negative prediction values between the two kits were observed at individual clinics, indicating that the results could be affected by clinic-related techniques for sampling and kit handling. Importantly, many patients (especially influenza-negative cases) were prescribed anti-influenza drugs that were incongruous with their condition, largely due to physician preference for patient responses to questionnaires and patient symptomology, as opposed to actual viral presence. Conclusions/SignificanceConcomitant use of SEA-IC and PDM-IC kits increased the likelihood of correct influenza diagnosis. Increasing the credibility of POCT is anticipated to decrease the inappropriate dispensing of anti-influenza drugs, thereby minimizing the emergence of drug-resistant H1N1pdm strains.背景： 针对季节性流感的临床诊断，临床医师通常依赖针对季节性流感病毒开发的市售试剂盒开展床旁检测（point-of-care testing, POCT）。然而，现有试剂盒对甲型流感大流行病毒（H1N1pdm）的检测灵敏度偏低，因此尚未建立针对该病毒感染的标准化床旁检测方法。 研究方法与主要结果： 本研究基于抗H1N1pdm的单克隆抗体制备了一款免疫层析（immunochromatography, IC）检测试剂盒，该试剂盒不会与季节性甲型或乙型流感病毒发生交叉反应。将本试剂盒（PDM-IC试剂盒）用于H1N1pdm感染诊断的效能，与现有的季节性流感病毒检测试剂盒（SEA-IC试剂盒）进行了对比。2010/2011年冬季，我们从日本大阪13家诊所的流感样综合征患者中采集了鼻拭子样本（n=542）。在全部542份样本中，随机选取332份（n=332）通过逆转录聚合酶链反应（reverse transcriptase polymerase chain reaction, RT-PCR）进一步检测病毒存在情况。结果显示，尽管两种试剂盒之间、或试剂盒与RT-PCR结果之间存在若干不一致之处，但PDM-IC试剂盒对H1N1pdm的检测灵敏度和特异性均优于SEA-IC试剂盒。使用SEA-IC试剂盒时，假阴性与假阳性病例的数量更多。两家试剂盒在各诊所的灵敏度、特异性及阴性预测值均呈现显著相关性，表明检测结果可能受到各诊所采样与试剂盒操作相关技术的影响。值得注意的是，由于医师更倾向于参考患者的问卷反馈与症状表现，而非实际的病毒感染状态，诸多患者（尤其是流感检测阴性者）被开具了与病情不符的抗流感药物。 结论与意义： 联合使用SEA-IC与PDM-IC试剂盒可提升流感诊断的准确性。提升床旁检测的可信度，有望减少抗流感药物的不合理开具，从而最大限度降低耐药性H1N1pdm毒株的出现概率。