Sample-Pooling Strategy for SARS-CoV-2 Detection among Students and Staff of the University of Sannio

Evaluation of FAST COVID-19 SARS-CoV-2 Antigen Rapid Test Kit for Detection of SARS-CoV-2 in Respiratory Samples from Mildly Symptomatic or Asymptomatic Patients

Molecular tests are the gold standard to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection but are associated with a diagnostic delay, while antigen detection tests can generate results within 20 min even outside a laboratory. In order to evaluate the accuracy and reliability of the FAST COVID-19 SARS-CoV-2 Antigen Rapid Test Kit (Ag-RDT), two respiratory swabs were collected simultaneously from 501 patients, with mild or no coronavirus disease 2019 (COVID-19)-related symptoms, and analyzed with both the Reverse Transcriptase-quantitative Polymerase Chain Reaction (RT-qPCR) and the FAST COVID-19 SARS-CoV-2 Antigen Rapid Test. Results were then compared to determine clinical performance in a screening setting. We measured a precision of 97.41% (95% CI 92.42–99.15%) and a recall of 98.26% (95% CI 93.88–99.25%), with a specificity of 99.22% (95% CI 97.74–99.74%), a negative predictive value of 99.48% (95% CI 97.98–99.87%), and an overall accuracy of 99.00% (95% CI 97.69–99.68%). Concordance was described by a Kappa coefficient of 0.971 (95% CI 0.947–0.996). Considering short lead times, low cost, and opportunities for decentralized testing, the Ag-RDT test can enhance the efforts to control SARS-CoV-2 spread in several settings.

Recent advances in methods for the diagnosis of Corona Virus Disease 2019

Since the beginning of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic, it has been clear that effective methods for the diagnosis of Corona Virus Disease 2019 (COVID-19) are the key tools to control its epidemic. The current gold standard for diagnosing COVID-19 is the real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR), which is a sensitive and specific method to detect SARS-CoV-2. Other RNA-based methods include RNA sequencing (RNA-seq), droplet digital reverse transcription-polymerase chain reaction (ddRT-PCR), reverse transcription loop-mediated isothermal amplification (RT-LAMP), and clustered regularly interspaced short palindromic repeats (CRISPR). The serological testing of antibodies (IgM and IgG), nanoparticle-based lateral-flow assay, and enzyme-linked immunosorbent assay (ELISA) can be used to enhance the detection sensitivity and accuracy. Because antibodies are usually detected a week after the onset of symptoms, these tests are used to assess the overall infection rate in the community. Sine the fact that healthcare varies from country to country across the world, different types of diagnosing COVID-19 imaging technologies including chest computed tomography (CT), chest radiography, and lung ultrasound are used in different degrees. Besides, the pooling test is an important public health tool to reduce cost and increase testing capacity in low-risk area, while artificial intelligence (AI) may aid to increase the diagnostic efficiency of imaging-based methods. Finally, depending on the type of samples and stages of the disease, a combination of information on patient demographics and histories, clinical symptoms, results of molecular and serological diagnostic tests, and imaging information is highly recommended to achieve adequate diagnosis of patients with COVID-19.

Prospective evaluation of specimen pooling strategy for detection of SARS-CoV-2 using pools of five and six specimens

The increased demand for SARS-CoV-2 molecular testing during the COVID-19 pandemic resulted in shortage of reagents and consumables. Pooling of specimens could be an alternative strategy to overcome these problems. Initial evaluation of the pooling strategy was performed using known positive specimens, previously tested individually, and their respective pools of plus four (5X), five (6X) and nine (10X) known negative specimens. Subsequently, 35 positive 5X and 35 positive 6X pools containing only one positive specimen per pool were analyzed prospectively regarding the difference in Ct values in pooled versus individual specimens. When the number of samples in the pool were five or six, the average deviation of Ct differences was < 1; therefore, this strategy was followed in the prospective study. Significant difference in Ct values was observed in positive specimens when tested individually and in 5X pools (p = 0.006), while the difference was not significant when positive specimens were tested individually and in 6X pools (p = 0.07). The difference in Ct values was not significant between the 5X and 6X pools. Testing in pools of five or six specimens is a reliable option for SARS-CoV-2 RNA detection when mass testing is needed.