The US Food and Drug Administration on Monday granted Emergency Use Authorization to two lab-developed real-time RT-PCR tests for SARS-CoV-2, the virus that causes coronavirus disease COVID-19. The authorized tests are performed at Knoxville, Tennessee-based Integrity Laboratories, and in the pathology laboratory of Florida-based Baptist Hospital Miami, part of Baptist Health South Florida.

The authorizations mark the 11th and 12th high-complexity molecular-based LDTs to be granted EUA by the FDA.

The test from Integrity Labs detects SARS-CoV-2 in nasal, nasopharyngeal, and oropharyngeal swabs. It detects the N1 and N2 targets from the EUA Centers for Disease Control and Prevention assay kit using primers and probes from IDT. The probe-based test is adapted for automated extraction using the Applied Biosystems MagMax, using Twist Biosciences control reagents and Thermo Fisher Scientific TaqPath 1-step RT-qPCR Master Mix. It runs on the Applied Biosystems QuantStudio 12K Flex RealTime PCR System.

The Integrity Labs test has a limit of detection of 10 viral copies per microliter. It was also assessed using 65 negative patient samples and 13 SARS-CoV-2 positive samples collected from four different institutions in Tennessee, and demonstrated 100 percent positive and negative percent agreement compared to results from other reference labs.

The lab has also performed a bridging study to show Amies medium would be a suitable substitute for viral transport media.

As per FDA guidelines issued February 29, high-complexity commercial, academic, or government labs are allowed to develop and begin using validated COVID-19 tests before the agency has completed review of their EUA requests. According to its website, Integrity Laboratories began testing for SARS-CoV-2 on March 23.

The test from Baptist Hospital Miami is also a probe-based real-time RT-PCR assay. It is validated for nasopharyngeal and oropharyngeal swabs and uses primers and probes for the CDC N2 target supplied by IDT. It relies on Promega Maxwell viral nucleic acid extraction, and uses the SeraCare AccuPlex SARS-CoV-2 Reference Material Kit, the TaqPath 1-Step RT-qPCR Master Mix, and the Applied Biosystems QuantStudio 7 Flex. 

The Baptist Hospital Miami test has a limit of detection of 2 viral copies per microliter. The test was compared to results obtained using the Abbott RealTime SARS-CoV2 assay on the M2000 platform for 60 patient samples, with a 93 percent positive agreement and 97 percent negative agreement.