Comparative evaluation of SARS-CoV-2 laboratory testing data sources for U.S. COVID-19 public health surveillance,...

SARS-CoV-2 laboratory testing data were collected by the U.S. Centers for Disease Control and Prevention for surveillance during the COVID-19 pandemic response. Understanding how these existing data correlate and diverge can help guide their use and interpretation.

We evaluated COVID-19 Electronic Laboratory Reporting (CELR), the National Respiratory and Enteric Virus Surveillance System (NREVSS), Increasing Community Access to Testing, Treatment and Response (ICATT) program, and commercial laboratory data from 2020 to 2024. SARS-CoV-2 testing volume, viral activity, and viral activity trends were calculated for each source during periods marked by key events. Key events included Delta and Omicron variant emergence, at-home testing availability, and public health emergency conclusion. Viral activity was characterized by percent positivity, the median percent of tests positive for SARS-CoV-2. Viral activity trends were measured using Spearman's correlation coefficients of normalized percent positivity between NREVSS and each of the data sources, along with match rates between the two sources from weekly trajectory categorization (increasing, stable, decreasing) comparisons.

SARS-CoV-2 testing volume decreased across time, most notably since January 2022. Viral activity measures showed that CELR (8.4%) and NREVSS (7.7%) had lower median weekly percent positivity compared to ICATT (18.5%) and commercial laboratories (11.0%). Viral activity trends between NREVSS and CELR (ρ = 0.93) and NREVSS and commercial laboratory (ρ = 0.85) were highly correlated, and less correlated between NREVSS and ICATT (ρ = 0.58). Week-to-week trajectory match rates indicated concordant viral trends across data sources with 89% for CELR, 79% for commercial laboratories, and 67% for ICATT when compared to NREVSS.

ICATT and commercial laboratory data sources consistently reported higher activity levels than CELR and NREVSS, suggesting differences in testing and care-seeking among the underlying populations represented, and the effects of varying reporting practices over time. However, trend correlations with NREVSS were high and few differences were observed in week-to-week trajectories. While these findings may be in part due to overlap in data sources, they also suggest that viral activity trends were relatively consistent across sources. A broad set of laboratory-based surveillance data sources effectively captured trends in SARS-CoV-2 circulation despite the evolving nature of testing and reporting during and after the COVID-19 pandemic.