Improvement of SARS-COV-2 screening using pooled sampling testing in limited RT-qPCR resources

Abstract

Background COVID-19 is a worldwide pandemic representing the most challenging global health crisis currently. Screening tests availability are a problematic task due to resource-limited abilities of some countries using RT-qPCR technique for SARS-COV-2 detection. Objective To cope with these health emergencies, in particular with this COVID-19 pandemic, states with low molecular diagnostic resources must optimize their capacity in molecular tests. We aimed to design a simple and effective strategy to improve inputs in the RT-qPCR tests as we attempted to check the financial advisability of using such an approach by calculating reduction rate of the test unit cost. Methods The used RNA was taken from suspected Covid-19 positive people. Nasopharyngeal swabs were collected at Pasteur Institute Diagnostic Center, Constantine, Algeria, 2020. We have optimized a screening strategy by grouping 16 individuals per pool, without reducing the sensitivity of RT-qPCR. Results A 1/16 dilution of a positive sample was a practical limit that does not require the use of robotic systems or mathematical modeling to construct the pools. The financial analysis of our strategy has shown that the costs can be reduced to 90%. The pooled testing strategy that was proven in this study could be recommended to help COVID-19 containment in countries with low potential screening infrastructures using RT-qPCR technique by reducing the number of tests required to identify all positive subjects.

Statistical modeling and evaluation of the impact of multiplicity classification thresholds on the COVID-19 pool testing accuracy

“…A main objective of prior research was to improve the efficiency of pool testing by minimizing the number of required tests which consequently reduces the cost of the testing process [ 21 ]. Bish et al [ 22 ] develop a robust model based on the Dorfman pool testing method to determine optimal pool size assuming that the perfect test specificity with the objective of reducing the total number of tests.…”

Optimization of Screening Strategies for COVID-19: Scoping Review

“…In the PCR test, the sensitivity would decrease and the specificity would increase in a pooled sample test owing to the dilution effect [61], which needs to be considered in the calculation of the optimal pool size [62]. The maximum pool size recommended in previous studies varies from 8 to 30 [63][64][65]. The sensitivity of the individual test and the influence of the dilution effect of pooling on sensitivity are related to the specific techniques of sampling and testing (such as sampling tools, sample processing reagents, detection instruments, and standardization of operation); therefore, test accuracy is an important determinant for the selection of pool size.…”