Harmonization of Real-World Data for Vaccine-Preventable Infectious Diseases: Integration of SARS-CoV-2 Diagnostic and Serologic Data from Multiple Sources

BackgroundThe COVID-19 Real World Data infrastructure (CRWDi) was established to study the impact of COVID-19 on patients with immunocompromising conditions. A key challenge was harmonizing SARS-CoV-2 molecular and serologic laboratory test results. Methods. There were 27 different test names for SARS-CoV-2 nucleic acid amplification tests (NAAT); and 34 and 26 for SARS-CoV-2 qualitative and semi-quantitative serologic tests, respectively. We validated a recoding strategy to eliminate the multiplicity of test names and results, and harmonized SARS-CoV-2 semi-quantitative serology test results by target antigen and antibody; published conversion factors were used to report data on a uniform Binding Arbitrary Units (BAU) scale. ResultsFor 5 200 000 patients, the number of unique SARS-CoV-2 test events were: 4 865 431 NAAT; 3 092 198 qualitative; and 834 487 semi-quantitative serology tests, of which 378 522 were anti-spike (S) semi-quantitative serology. In achieving harmonization of semi-quantitative serologic results, semilog cumulative ordinal plots demonstrated that test results from patients with transplantation exhibited a higher proportion of negative-and-submaximal SARS-CoV-2 anti-S BAU values, when compared to patients with cancer or systemic autoimmune or rheumatic diseases (SARDs), or to a general non-immunocompromised population. ConclusionsComplex and heterogeneous test name and result conventions represent a significant barrier to understanding real-world laboratory data for SARS-CoV-2. The generalizable methodology described herein permits successful harmonization of test data from multiple laboratory sources with administrative claims data, vital status data, and structured data on cancer diagnostics and treatment. This methodology supports exploration of the utility of semi-quantitative serologic data in all patients, especially those with immunocompromising conditions. SummaryWe present a strategy for harmonizing real-world laboratory test results, based on the COVID-19 Real World Data infrastructure (CRWDi). By successfully addressing this barrier, this strategy is of general value for studying the clinical utility of laboratory testing.