Sensitivity of Rapid Diagnostic Test Compared to qRT-PCR in the COVID-19 Management Strategy in Tunisia

The objective of this chapter isto investigatethe benefit of the rapid antigenic detection of SARS-CoV-2 and to demonstrate the contribution of this technique compared to real-time RT-PCR.

In this study, the SARS-CoV-2 nucleocapsid N antigen rapid diagnostic test (Standard Covid-19 Ag Test, SD Biosensor) was performed. The sample size of the study was49 patients. Real-time RT-PCR testing was performed only in 12 patients. Extraction kit (Model: VDR-B096V) was used for the extraction of nucleic acids from various cell types. The extracted nucleic acids are applicable to PCR, real-time PCR, enzymatic reactions and others.

Nasopharayngeal swabs were taken from subjects whose mean age was 35 years (range 23-68 years) and who presented one of the following symptoms: dry cough (30.61%), chest tightness (28%), fever (28%), headache (24.48%), asthenia (22.44%) and diarrhea in only 14.28%. The time between the onset of symptoms and the completion of the test ranged from 0 to 2 days. In the chosen sample14 (28.57%) were positive and 35 (71.42%) were negative for all rapid tests performed. Of the samples tested, 44 came from different IMKO departments. RT-PCR was performed in 8 patients whose rapid tests were negative and gave a positive result in 2 cases. Considering the significance of the global public health emergency during the pandemic, it was necessary to carry out large studies to better understand the issue of potential SARS-CoV-2 recurrence in COVID-19 patients.

Due to the limited proportion of patients with prolonged SARS-Cov-2 RNA conversion and the high false negative rate of viral test results, recurrence of positive SARS-Cov-2 may experience from false negative RT-PCR results.

SARS-Cov-2 reactivation or re-infection will be a persistent and vexing problem.

It has been observed that the detection of SARS-CoV-2 needs to be evaluated and compared to the standard RT-PCR technique, which often offers significantly better sensitivity.