Department of Medicine, University of Lagos, Idi-Araba, Lagos, Nigeria.
Department of Medicine, Lagos University Teaching Hospital, Lagos, Nigeria.
Niger Postgrad Med J. 2022 Apr-Jun;29(2):96-101. doi: 10.4103/npmj.npmj_779_21.
The use of reverse transcription-polymerase chain reaction (RT-PCR) is the gold standard laboratory test for diagnosing SARS-CoV-2 infection. However, it has the disadvantage of a long turnaround time and cost. The Nigeria Centre for Disease Control (NCDC) formulated a case definition for COVID-19. We sought to determine the utility of a 14-item, point-weighted clinical screening questionnaire adapted from the NCDC case definition in identifying patients more likely to have the disease. This was to aid prompt clinical decision-making.
We retrospectively reviewed the data of 113 non-surgical patients presenting to the Accident and Emergency Department (A and E) of Lagos University Teaching Hospital, Lagos, Nigeria. Patients were stratified based on screening scores into low (0-2), moderate (3-5) and high (6) pre-test categories. Patients with low and high scores ≥6 were admitted to the A and E and the COVID-19 holding ward, respectively, while the moderate group had chest computed tomography scans to aid further decision-making, pending the outcome of their RT-PCR results. The validity of the triage score as compared to the RT-PCR test result was calculated and the kappa score of agreement was utilised to evaluate the concordance between two triage scores. The optimum cut-off score was also obtained based on the maximal Younden's index.
The frequencies of low, moderate and high pre-test scores were 34 (30%), 43 (38.1%) and 36 (31.9%), respectively. Overall, 38.1% (43/113) were RT-PCR positive. RT-PCR was positive in 26.5% (9/34) with low screening scores, 55.8% (24/43) with moderate scores and 27.8% (10/36) with high scores. The sensitivity and specificity of a high score of 6 were 25% and 92.86%, while the lower score of 3 had sensitivity and specificity of 62.5% and 58.6%, respectively.
The screening tool showed a high specificity in its initial design, which suggests that anyone with a low score using this tool has a high probability of testing negative. We recommend a cut-off score of 4 (score A) or 6 (score B) of the current screening tool be used to increase the chances of identifying persons with COVID-19 for RT-PCR testing.
本研究旨在确定一种从尼日利亚疾病控制中心（NCDC）COVID-19 病例定义改编而来的 14 项、点加权临床筛查问卷，用于识别更可能患有该病的患者，以辅助及时的临床决策。
我们回顾性分析了 113 例非手术患者在拉各斯大学教学医院急诊科就诊的数据。根据筛查评分，患者分为低（0-2）、中（3-5）和高（6）预测试分类。低和高评分≥6 的患者分别被收入急诊科和 COVID-19 暂存病房，而中评分组则进行胸部计算机断层扫描，以辅助进一步决策，同时等待 RT-PCR 结果。计算了分诊评分与 RT-PCR 检测结果的有效性，并使用kappa 评分评估了两种分诊评分的一致性。还根据最大 Younden 指数获得了最佳截断评分。
低、中、高预测试评分的频率分别为 34（30%）、43（38.1%）和 36（31.9%）。总体而言，38.1%（43/113）的 RT-PCR 阳性。低评分组中 RT-PCR 阳性率为 26.5%（9/34），中评分组为 55.8%（24/43），高评分组为 27.8%（10/36）。评分≥6 的敏感性和特异性分别为 25%和 92.86%，而评分≤3 的敏感性和特异性分别为 62.5%和 58.6%。
该筛查工具在最初设计时具有较高的特异性，这表明使用该工具的低评分者检测结果呈阴性的可能性较高。我们建议将目前筛查工具的截断评分设为 4（评分 A）或 6（评分 B），以提高识别 COVID-19 患者进行 RT-PCR 检测的机会。
