Clinical Outcome of PCR-Negative COVID-19 Patients: A Retrospective Study.

Objective: To evaluate the clinical features and outcomes of patients who were admitted with a diagnosis of coronavirus disease 2019 (COVID-19) but who were not confirmed with polymerase chain reaction (PCR) positivity.

Material and methods: This is a retrospective analysis of all patients admitted to two tertiary care centers between March 15 and May 15, 2020, with a diagnosis of COVID-19. From a common database prepared for COVID-19, we retrieved the relevant data and compared the clinical findings and outcomes of PCR-positive patients with those of PCR-negative cases who had been diagnosed on the basis of typical clinical and radiographic findings.

Results: A total of 349 patients were included in the analysis, of which 126 (36.1%) were PCR-negative. PCR-negative patients were younger (54.6 ± 20.8 vs. 60.8 ± 18.9 years, P = .009) but were similar to PCR-positive patients in terms of demographics, comorbidities, and presenting symptoms. They had higher lymphocyte counts (1519 ± 868 vs. 1331 ± 737/mm3, P = .02) and less frequently presented with bilateral radiographic findings (68.3% vs. 79.4%, P = .046) than PCR-positive patients. Besides, they had less severe disease and better clinical outcomes regarding admission to the intensive care unit (9.6% vs. 20.6%, P = .023), oxygen therapy (21.4% vs. 43.5%, P < .001), ventilatory support (3.2% vs. 11.2%, P = .03) and length of hospital stay (5.0 ± 5.0 vs. 9.7 ± 5.9 days, P < .001).

Conclusion: This study confirms that about one-third of the COVID-19 patients are PCR-negative and diagnosed based on clinical and radiographic findings. These patients have a more favorable clinical course, shorter hospital stays, and are less frequently admitted to the intensive care unit.