A-236 Rapid multiplexed PCR (polymerase chain reaction) tests for respiratory disease improve process and time to diagnosis versus laboratory-based molecular testing
Authors: Chase J , Beaubrun A , Stockl K , Tucker J , Certa J , Becker L 
Published: October 2024

Abstract

Background
The Infectious Disease Society of America recommends molecular testing for symptomatic patients suspected of having COVID-19. Molecular tests can be performed at the point of care or in a centralized laboratory, using different methodologies, and can be singleplex or multiplex. Limited data are available examining the use of these tests in clinical practice and impact of different test types on patient outcomes; however, common antiviral treatments for both COVID-19 and influenza are more effective when taken earlier and are not indicated for use more than 5 and 2 days after symptom onset, respectively. The aim of this study was to describe the diagnostic journey for non-inpatients who received molecular testing for respiratory pathogens in the laboratory versus those who received testing using a rapid, multiplexed real-time RT-PCR test that can be performed at the point of care.

Methods
De-identified administrative claims were analyzed from July 1, 2020 through September 30, 2022 for commercially insured and Medicare Advantage enrollees in the Optum Labs Data Warehouse. Patients with ≥1 medical claim for a non-inpatient visit with a procedure code for testing for SARS-CoV-2 were identified; patients who received antigen testing at index were excluded. Patients were followed for up to 90 days. Two patient groups were selected for the final study sample: 1) Patients with ≥1 claim with CPT code 0240U or 0241U with a point-of-care or laboratory place of service on the index date (proprietary laboratory analyses codes for Xpert® Xpress CoV-2/Flu/RSV, or “Xpert Xpress”); and 2) Patients with other laboratory-based molecular testing on the index date. Standardized difference of &gt;0.10 or &lt;-0.10 was considered a significant imbalance in proportions or means.

Results
In total, 51,602 patients received testing with Xpert Xpress while 317,192 received laboratory testing. Patients who were tested with Xpert Xpress were significantly older (mean 49.82 vs 42.19, SD 0.3), had a higher Charlson Comorbidity Index (mean 0.7 vs 0.35, SD 0.29), and were more likely to have a respiratory risk factor (6.09% vs 2.38%, SD 0.19). On average, patients who were tested with Xpert Xpress had significantly fewer tests for SARS-CoV-2 on the index date (mean 1.2 vs 1.58, SD -0.55), and fewer tests for SARS-CoV-2, influenza, or RSV on the index date and through the end of the 90-day fixed follow-up period (mean 1.64 vs 2.57, SD -0.45). They were also significantly more likely to be diagnosed with COVID-19 on the index date (23.31% vs 16.53%, SD 0.17). Among patients with a diagnosis for COVID-19, mean time to diagnosis was significantly shorter among patients tested with Xpert Xpress (4.85 vs 8.86 days, SD -0.27; median 0 vs 4 days). This finding was also consistent for influenza (4.05 vs 20.28 days, SD -0.74; median 0 vs 5 days).

Conclusions
Testing with Xpert Xpress at index resulted in fewer total tests and faster diagnosis compared to testing in the laboratory. Rapid, multiplex PCR testing provides a faster time to diagnosis and may support more appropriate and effective treatment.