Kutima Bernadette, Kagucia Eunice Wageci, Mwai Kennedy, Kimani Makobu, Sigilai Antipa, Mugo Daisy, Karanja Henry, Gitonga John N, Karani Angela, Akech Donald, Toroitich Monica, Karia Boniface, Tuju James, Ziraba Abdhalah K, Bigogo Godfrey, Ochieng Caroline, Onyango Clayton, Lidechi Shirley, Munywoki Patrick K, Uyoga Sophie, Adetifa Ifedayo M O, Oyier Lynette I Ochola, Bejon Philip, Scott J Anthony G, Agweyu Ambrose, Warimwe George M, Nyagwange James
KEMRI-Wellcome Trust Research Programme, Center for Geographic Medicine Research, Coast, Kilifi, Kilifi County, P.O Box 230-80108, Kenya.
African Population and Health Research Center, Nairobi, Nairobi County, P.O. Box 10787, 00100, Kenya.
Wellcome Open Res. 2025 Jul 28;9:349. doi: 10.12688/wellcomeopenres.20240.2. eCollection 2024.
The InBios SCoV-2 Detect™ IgG ELISA (InBios) and the in-house KWTRP ELISA (KWTRP) have both been used in the estimation of SARS-CoV-2 seroprevalence in Kenya. Whereas the latter has been validated extensively using local samples, the former has not. Such validation is important for informing the comparability of data across the sites and populations where seroprevalence has been reported.
We compared the assays directly using pre-pandemic serum/plasma collected in 2018 from 454 blood donors and 173 malaria cross-sectional survey participants, designated gold standard negatives. As gold standard SARS-CoV-2 positive samples: we assayed serum/plasma from 159 SARS-CoV-2 PCR-positive patients and 166 vaccination-confirmed participants.
The overall agreement on correctly classified samples was >0.87 for both assays. The overall specificity was 0.89 (95% CI, 0.87-0.91) for InBios and 0.99 (95% CI, 0.97-0.99) for KWTRP among the gold standard negative samples while the overall sensitivity was 0.97 (95% CI, 0.94-0.98) and 0.93 (95% CI, 0.90- 0.95) for InBios and KWTRP ELISAs respectively, among the gold standard positive samples. In all, the positive predictive value for InBios was 0.83 (95% CI, 0.79-0.87) and 0.98 (95% CI, 0.96-0.99) for KWTRP while the negative predictive value was 0.98 (95% CI, 0.97- 0.99) and 0.97 (95% CI, 0.95-0.98) for InBios and KWTRP respectively.
Overall, both assays showed sufficient sensitivity and specificity to estimate SARS-CoV-2 antibodies in different populations in Kenya.
InBios SCoV-2 Detect™ IgG酶联免疫吸附测定法（InBios）和内部KWTRP酶联免疫吸附测定法（KWTRP）均已用于估算肯尼亚的新冠病毒血清流行率。尽管后者已使用当地样本进行了广泛验证，但前者尚未进行。这种验证对于了解不同地点和人群中已报告血清流行率的数据可比性非常重要。
我们直接比较了这两种检测方法，使用了2018年从454名献血者和173名疟疾横断面调查参与者中采集的疫情前血清/血浆，将其指定为金标准阴性样本。作为金标准新冠病毒阳性样本：我们检测了159名新冠病毒PCR检测呈阳性患者和166名疫苗接种确认参与者的血清/血浆。
两种检测方法对正确分类样本的总体一致性均>0.87。在金标准阴性样本中，InBios的总体特异性为0.89（95%可信区间，0.87-0.91），KWTRP为0.99（95%可信区间，0.97-0.99）；而在金标准阳性样本中，InBios和KWTRP酶联免疫吸附测定法的总体敏感性分别为0.97（95%可信区间，0.94-0.98）和0.93（95%可信区间，0.90-0.95）。总体而言，InBios的阳性预测值为0.83（95%可信区间，0.79-0.87），KWTRP为0.98（95%可信区间，0.96-0.99）；而InBios和KWTRP的阴性预测值分别为0.98（95%可信区间，0.97-0.99）和0.97（95%可信区间，0.95-0.98）。
总体而言，两种检测方法均显示出足够的敏感性和特异性，可用于估算肯尼亚不同人群中的新冠病毒抗体。
