三种商业性 II 期 IgM ELISA 试剂盒用于急性 Q 热血清筛查时的可靠性。
Unreliability of three commercial phase II IgM ELISA kits for the seroscreening of acute Q fever in human cases.
机构信息
Department of Microbiology, Mahatma Gandhi Medical College & Research Institute, Puducherry, India.
Department of General Medicine, Indira Gandhi Government General Hospital & Post Graduate Institute, Puducherry, India.
出版信息
Indian J Med Res. 2017 Sep;146(3):386-391. doi: 10.4103/ijmr.IJMR_1815_15.
BACKGROUND & OBJECTIVES: Seroprevalence of Q fever (QF) caused by Coxiella burnetii has been reported from different parts of India. Usually serological/molecular tests are employed for detection of infection. The present study was undertaken to verify the validity of three different QF phase II IgM ELISA kits for acute QF diagnosis by comparing with the gold standard indirect fluorescent antibody assay (IFA).
METHODS
Fifty eight serum samples collected from 42 patients (26 patients provided acute sample only and 16 both acute and convalescent samples) which were examined by all three commercial kits, were cross-checked with QF Phase II IgM IFA for confirmation.
RESULTS
Eleven patients were positive for C. burnetii antibodies by IFA in acute and/or convalescent serum samples. Taking IFA as a reference, percentages of sensitivity, specificity, positive predictive value and negative predictive value for Virion-Serion/Vircell/NovaTec were 36.36, 61.29, 25.00, 73.08; 81.82, 35.48, 31.03, 84.62 and 100, 25.81, 32.35, 100 per cent, respectively.
INTERPRETATION & CONCLUSIONS: The three different ELISA kits exhibited poor agreement amongst them and unacceptable level of false positivity. IFA remains to be the only option for diagnosing acute QF. Discrepancy between the clinical findings and IFA/ELISA results needs confirmation by C. burnetii DNA detection in real-time polymerase chain reaction.
背景与目的
在印度的不同地区均有报道称，由贝氏柯克斯体引起的 Q 热（QF）血清流行率。通常采用血清学/分子检测来检测感染。本研究旨在通过与金标准间接荧光抗体检测（IFA）比较，验证三种不同的 QF 二期 IgM ELISA 试剂盒在急性 QF 诊断中的有效性。
方法
对 42 例患者的 58 份血清样本（26 例患者仅提供急性期样本，16 例患者同时提供急性期和恢复期样本）进行了检测，采用三种商业试剂盒进行检测，并用 QF 二期 IgM IFA 交叉检查进行确认。
结果
IFA 在急性和/或恢复期血清样本中检测到 11 例患者的 C. burnetii 抗体阳性。以 IFA 为参考，Virion-Serion/Vircell/NovaTec 的灵敏度、特异性、阳性预测值和阴性预测值分别为 36.36%、61.29%、25.00%、73.08%；81.82%、35.48%、31.03%、84.62%和 100%、25.81%、32.35%、100%。
结论与解释
三种不同的 ELISA 试剂盒之间的一致性较差，假阳性率也不能接受。IFA 仍然是诊断急性 QF 的唯一选择。临床发现与 IFA/ELISA 结果之间的差异需要通过实时聚合酶链反应检测 C. burnetii DNA 来确认。
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