Department of Immunology, University of Ibadan.
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Niger J Physiol Sci. 2020 Dec 31;35(2):117-121.
The challenges associated with adequate deployment of nucleic acid amplification tests (NAATs) in developing countries underscores the important role of simple but sensitive and specific serological testing kits in COVID-19 diagnosis. Presently, there are a number of point-of-care tests for Severe Acute Respiratory Syndrome Corona Virus-2 (SARS-CoV-2) screening. However, the reliability of these test kits is poorly documented and hence, needs to be ascertained. This study was therefore designed to determine the sensitivity and specificity of two serological test kits for COVID-19 screening with the view to providing necessary information on the suitability of their deployment as routine test kits for SARS-CoV-2 in Nigeria. Forty-seven (47) asymptomatic adults who had been tested for SARS-CoV-2 with the real-time reverse-transcriptase polymerase-chain reaction (RT-PCR) were enrolled into this study. Blood samples were obtained for qualitative determination of serum IgM and IgG antibodies to the S-antigen of SARS-CoV-2 using a commercially available IgM and IgG Rapid Diagnostic Test (RDT) and enzyme linked immunosorbent assay (ELISA). The association between the test kits (ELISA and RDT) and PCR in diagnosing COVID-19 was determined using the Fisher's Exact test at P<0.05. The sensitivity and specificity of the test kits were determined using ROC while the Positive Predictive Value (PPV), Negative Predictive Value (NPV), Positive Likelihood Ratio (PLR), Negative Likelihood Ratio (NLR), Diagnostic Odds Ratio (DOR) and accuracy were calculated as appropriate. Twenty-eight (59.6%) of the study participants had positive PCR result. ELISA and RDT identified 20 (42.6%) and 13 (27.7%) participants respectively as having anti- SARS COV-2 specific antibodies. ELISA had a better sensitivity performance, NPV, PLR, DOR and accuracy than the RDT while the RDT had a better specificity performance than ELISA. The proportion of participants with anti-SARS-CoV-2 IgM antibody identified using ELISA was significantly higher compared with RDT. In contrast, the proportion of participants with positive anti- SARS COV-2 IgG antibody identified using RDT was significantly higher compared with ELISA. ELISA has a better sensitivity for detecting anti-SARS-CoV-2 Spike-protein specific antibodies than the RDT. However, combination of RDT and ELISA for the detection of anti-SARS-COV-2 antibodies might be useful for population COVID-19 screening.
在发展中国家充分部署核酸扩增检测（NAATs）面临的挑战突显了简单但敏感和特异的血清学检测试剂盒在 COVID-19 诊断中的重要作用。目前，有许多用于严重急性呼吸系统综合征冠状病毒 2（SARS-CoV-2）筛查的即时检测（POC）。然而，这些检测试剂盒的可靠性记录很差，因此需要确定。本研究旨在确定两种用于 COVID-19 筛查的血清学检测试剂盒的敏感性和特异性，以期为其在尼日利亚作为 SARS-CoV-2 常规检测试剂盒的适用性提供必要信息。本研究纳入了 47 名无症状成年人，他们已通过实时逆转录酶聚合酶链反应（RT-PCR）检测 SARS-CoV-2。采集血液样本，使用市售的 IgM 和 IgG 快速诊断检测（RDT）和酶联免疫吸附试验（ELISA）定性测定血清中针对 SARS-CoV-2 S 抗原的 IgM 和 IgG 抗体。使用 Fisher's 精确检验确定检测试剂盒（ELISA 和 RDT）与 PCR 诊断 COVID-19 的相关性（P<0.05）。使用 ROC 确定检测试剂盒的敏感性和特异性，同时计算阳性预测值（PPV）、阴性预测值（NPV）、阳性似然比（PLR）、阴性似然比（NLR）、诊断比值比（DOR）和准确性。研究参与者中有 28 人（59.6%）的 PCR 结果为阳性。ELISA 和 RDT 分别识别出 20 名（42.6%）和 13 名（27.7%）参与者具有针对 SARS COV-2 的特异性抗体。与 RDT 相比，ELISA 的敏感性、NPV、PLR、DOR 和准确性表现更好，而 RDT 的特异性表现优于 ELISA。与 RDT 相比，使用 ELISA 检测到的 SARS-CoV-2 IgM 抗体的参与者比例显著更高。相比之下，使用 RDT 检测到的 SARS-CoV-2 IgG 抗体阳性的参与者比例显著高于 ELISA。ELISA 检测 SARS-CoV-2 刺突蛋白特异性抗体的敏感性优于 RDT。然而，RDT 和 ELISA 联合检测抗 SARS-COV-2 抗体可能有助于人群 COVID-19 筛查。
