Re-testing as a method of implementing external quality assessment program for COVID-19 real time PCR testing in...

Area of Science:

• Molecular diagnostics
• Public health
• Infectious disease surveillance

Background:

• COVID-19 diagnostics have seen significant advancements.
• The Uganda Virus Research Institute (UVRI) was tasked with ensuring diagnostic quality.
• Re-testing of samples was implemented by UVRI for external quality assessment of COVID-19 molecular diagnostics.

Purpose of the Study:

• To assess the performance agreement of COVID-19 molecular diagnostics in Ugandan laboratories.
• To evaluate the accuracy of primary testing laboratories against the national reference laboratory.
• To identify discrepancies in COVID-19 testing and inform quality improvement strategies.

Main Methods:

• Participating laboratories submitted archived nasopharyngeal samples and metadata to UVRI.
• Samples were re-tested at UVRI using the WHO Berlin protocol.
• Results were compared to primary laboratories, with analysis using Ms Excel and GraphPad Prism.

Main Results:

• 45% of primary laboratories showed 100% performance agreement with UVRI for final test results.
• Differences in Cycle Threshold (CT) values were observed even with concordant results.
• False positives were detected in 55% of laboratories, originating from public, private not-for-profit, and private sectors.

Conclusions:

• False positives were found across different types of testing laboratories in Uganda.
• There is a critical need for standardization of molecular testing platforms nationwide.
• Improvements in laboratory quality management systems are essential to reduce testing discrepancies.