New technique could massively boost testing capacity
One of the most pressing challenges in the fight against COVID-19 is the need for nearly all affected countries to dramatically increase their capacity to test for the disease.
The large proportion of asymptomatic carriers of SARS-COV-2 makes it vitally important to test as many members of an affected population as possible, both to quarantine individuals and to know which containment measures are appropriate.
Mass manufacturing of the necessary number of test kits is difficult due to the exhaustive quality control required, and also the reagents used which must be produced organically and then purified. However, researchers at the Stanford Health Care Clinical Virology Laboratory may have helped prove one method of making existing kits go further.
The team’s retrospective study conducted pooled sample tests of nasopharyngeal and bronchoalveolar lavage samples collected in the San Francisco Bay Area from 1-26 January 2020, before individual SARS-COV-2 testing commenced.
The 2,888 samples were grouped into pools of 9-10. Three of the pools tested positive, of which two were reproducible by testing individual samples.
The efficiency of this technique, combined with the only slight loss of sensitivity and maintenance of specificity, makes this a successful first test of sample pooling for detection of early community transmission of SARS-COV-2.
The authors point out that their results require more data to validate their approach, but their study is not the first to test sample pooling. A German research team recently demonstrated a similar method so successfully that the Science Ministry of the German State of Hessen has stated it could potentially increase Germany’s testing capacity up to tenfold without loss of diagnostic quality. An Israeli team has claimed to successfully test over 60 samples at a time, although they are yet to publish their results.
Hogan CA, Sahoo MK, Pinsky BA. Sample Pooling as a Strategy to Detect Community Transmission of SARS-CoV-2. JAMA. 2020 Apr 6. DOI: 10.1001/jama.2020.5445 [e-pub ahead of print]