Performance of an automated chemiluminescence SARS-COV-2 IG-G Assay.

ABSTRACT: INTRODUCTION:We describe our evaluation of the Abbott SARS-CoV-2 IgG assay on the Architect immunoassay analyser. METHODS:We assessed assay precision, sensitivity, specificity, positive/negative predictive values (PPV/NPV), cross-reactivity (influenza/dengue/hepatitis B and C/rheumatoid factor/anti-nuclear/double-stranded DNA/syphilis) and sample throughput in samples from real-time polymerase chain reaction (RT-PCR) positive patients/healthcare workers (HCWs)/pre-pandemic samples. We compared the cut-off indexes (COIs) between all control samples (HCWs and pre-pandemic) to generate an optimised COI limit for reactivity. RESULTS:The assay specificity was 99.8% (n=980) and sensitivity was 45.9-96.7% (n=279). When tested ?14 days post-positive RT-PCR (POS), the PPV/NPV was 96.4%/99.8%. The difference between the COIs of HCWs/pre-pandemic samples was small (0.01, p<0.0001). There was minimal cross-reactivity with other antibodies. A lower COI limit for reactivity (?0.55, using the 99th percentile COI of our controls and ROC analysis) improved diagnostic sensitivity, especially at 0-6 days POS (45.9% to 55.8%), with a small decrease in specificity (98.9%). The assay throughput was 100 samples in 70 min. CONCLUSION:The Abbott SARS-CoV-2 IgG assay shows excellent performance in patients ?14 days POS. The difference between the COIs of HCWs and pre-pandemic samples was numerically small. A lower COI limit improves assay sensitivity with a slight decrease in specificity.

SUBMITTER: Lau CS 

PROVIDER: S-EPMC7476884 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature