Saravanan R, Saradhai P, Rani E, Rajasekar V
Department of Biotechnology, Biomedical Engineering and Research Foundation, Periyar University, Salem, Tamil Nadu, India.
Indian J Med Microbiol. 2014 Jan-Mar;32(1):26-30. doi: 10.4103/0255-0857.124291.
Leptospirosis is a potentially fatal bacterial disease that mimics many diseases; therefore, laboratory confirmation is pivotal. Though microscopic agglutination test (MAT) is accepted as World Health Organisation (WHO) reference test, it has got many pitfalls such as being hazardous, tedious, cumbersome and expensive. Counterimmunoelectrophoresis (CIE) is popularly used for diagnosing many infectious diseases but rarely for Leptospirosis. The aim of this study is to find suitability of CIE for the routine laboratory diagnostic purposes.
Repeat sampling (paired sera) was possible from 401 subjects of which 181 were in-patients of Salem Government General and Private Hospitals and the remaining 220 MAT negative healthy College students gave their consent for the study. All the 802 sera samples were collected from January 2009 to November 2012 and subjected to the present study. After carrying out MAT and CIE on the suspected and control samples, a comparative evaluation was conducted. McNemars test method was used to find out the significant difference between the two tests in the early diagnosis.
The sensitivity, specificity, Positive Predictive value (PPV), Negative Predictive value (NPV) and Efficiency test for CIE were 96.80%, 89.28%, 95.23%, 92.59% and 94.47%, respectively. The corresponding values for MAT were 95.90%, 89.83%, 95.08%, 91.37% and 93.92%, respectively. There was no significant difference between MAT and CIE at 95% and 99% confidence intervals according to McNemars test. P value in the early stage of illness was greater for CIE than MAT when Polymerase Chain Reaction (PCR) was used as Gold Standard of diagnosis.
It was concluded that the CIE could be advantageous over MAT due to its safety, rapidity, simplicity, economic and easy for large number of samples. It can answer little earlier than MAT and found as reliable as that of MAT. Since both the tests had shown similar efficacies in the later stage of the illness, the importance could be given to CIE due to early diagnosis.
钩端螺旋体病是一种潜在致命的细菌性疾病，症状与多种疾病相似，因此实验室确诊至关重要。虽然显微镜凝集试验（MAT）被世界卫生组织（WHO）认可为参考检测方法，但它存在诸多缺陷，如具有危险性、操作繁琐、耗时且成本高昂。对流免疫电泳（CIE）广泛应用于多种传染病的诊断，但很少用于钩端螺旋体病的诊断。本研究旨在探讨CIE用于常规实验室诊断的适用性。
对401名受试者进行重复采样（配对血清），其中181名是塞勒姆政府综合医院和私立医院的住院患者，其余220名MAT检测阴性的健康大学生同意参与研究。所有802份血清样本于2009年1月至2012年11月采集，并进行本研究。对疑似样本和对照样本进行MAT和CIE检测后，进行比较评估。采用McNemars检验方法来找出两种检测方法在早期诊断中的显著差异。
CIE的敏感性、特异性、阳性预测值（PPV）、阴性预测值（NPV）和效能分别为96.80%、89.28%、95.23%、92.59%和94.47%。MAT的相应值分别为95.90%、89.83%、95.08%、91.37%和93.92%。根据McNemars检验，在95%和99%置信区间内，MAT和CIE之间无显著差异。当以聚合酶链反应（PCR）作为诊断金标准时，疾病早期CIE的P值大于MAT。
得出结论，CIE因其安全性、快速性、简便性、经济性以及适用于大量样本，可能比MAT更具优势。它比MAT能更早得出结果，且与MAT一样可靠。由于两种检测方法在疾病后期显示出相似的效能，鉴于能早期诊断，CIE更具重要性。
