Laboratory Medicine

As COVID-19 continues to strain public health systems and vaccination programmes race
against new variants that might be more transmissible or capable of evading immune
responses, the urgent need for simple, accessible, and frequent testing remains. Inexpensive,
scalable, and sustainable strategies that allow easily repeatable testing over time
need to be made widely available. This is possible by testing saliva.

Stites et al. discuss the interpretation of Covid-19 testing, highlighting probabilistic
interpretation with timely examples. As Covid-19 testing is rapidly changing and as
information on test performance is still being acquired, this perspective highlights
an approach that can adapt to new information and to new testing environments.

IDSA Guidelines on Antigen Testing for the Diagnosis of COVID-19 now available. These evidence-based rapid guidelines will address pressing clinical questions related to optimal use of SARS-CoV-2 Antigen tests in both medical and non-medical settings.

A new technology for COVID-19 detection has become available that is much simpler and faster to perform that currently-recommended nucleic acid amplification tests (NAAT), like PCR. This method relies on direct detection of SARS-CoV-2 viral proteins in nasal swabs and other respiratory secretions using a lateral flow immunoassay (also called an RDT) that gives results in < 30 minutes. Though these antigen detection RDTs (Ag-RDTs) are substantially less sensitive than NAAT, they offer the possibility of rapid, inexpensive and early detection of the most infectious COVID cases in appropriate settings. Acknowledging the inadequacy of current data on the performance and operational utility of these tests, this document seeks to provide guidance to countries on considerations for integration into COVID outbreak management programs.