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You may have heard that the Abbott IDNow rapid assay is not working as well as others (see here: https://www.biorxiv.org/content/10.1101/2020.05.11.089896v1)
The analysis is flawed
My opinion - it actually worked very well!
The failures owed almost entirely to sample collection technique - not assay.
1/n
The analysis is flawed
My opinion - it actually worked very well!
The failures owed almost entirely to sample collection technique - not assay.
1/n
In the first comparison, swabs were placed in solution (VTM). Per Abbott, the swabs should go directly into the IDNow instrument by design
Even with VTM, IDNow mostly missed those with very low viral copies that might be deemed negative on any other instrument too (ct >40)
2/n
Even with VTM, IDNow mostly missed those with very low viral copies that might be deemed negative on any other instrument too (ct >40)
2/n
On second comparison - comparison was between NP swabs on cepheid v anterior nare swab on Abbott.
This is a poor comparison. If comparing #COVID19 assays, keep the sampling the same. Don't collect a known poorer sample type and blame loss of sensitivity on assay.
#ClinPath101
This is a poor comparison. If comparing #COVID19 assays, keep the sampling the same. Don't collect a known poorer sample type and blame loss of sensitivity on assay.
#ClinPath101
On a different note - I'm surprised and impressed that Cepheid reports positives above a Ct of 40. It provides a terrific sensitivity.
Reporting Cts >40 takes massive trust in knowing you're free of non-specific amplification.
40 cycles amplifies a single hit 1 trillion times.
Reporting Cts >40 takes massive trust in knowing you're free of non-specific amplification.
40 cycles amplifies a single hit 1 trillion times.
