Sample pooling on the Cepheid Xpert® Xpress SARS-CoV-2 assay

Area of Science:

• Clinical diagnostics
• Molecular biology
• Infectious disease research

Background:

• The COVID-19 pandemic created a significant global demand for laboratory testing supplies.
• Sample pooling emerged as a strategy to conserve resources and maintain testing capacity.

Purpose of the Study:

• To evaluate the performance of the Cepheid Xpert® Xpress SARS-CoV-2 RT-PCR assay for detecting SARS-CoV-2 in pooled samples.
• To determine the feasibility of pooling samples in groups of 4 and 6 for COVID-19 testing.

Main Methods:

• Clinical samples, both positive and negative for SARS-CoV-2, were used to create sample pools.
• The Cepheid Xpert® Xpress SARS-CoV-2 RT-PCR assay was employed to test these pooled samples.
• Cycle threshold (Ct) values of positive samples in neat and pooled formats were analyzed.

Main Results:

• All clinical samples containing SARS-CoV-2 were qualitatively detected when tested in pools of 4 or 6.
• The median change in cycle threshold (Ct) values for positive samples was 2.0 in pools of 4 and 2.9 in pools of 6.
• The assay demonstrated reliable detection of SARS-CoV-2 in pooled samples.

Conclusions:

• Pooling samples in groups of 4 or 6 is a potentially effective strategy to enhance COVID-19 testing capacity.
• The Cepheid Xpert® Xpress SARS-CoV-2 RT-PCR assay performs well with pooled samples.
• This approach can help laboratories manage high testing demands efficiently.