The Ability of Serum Amyloid A to Discriminate Coronavirus Disease 2019 ( COVID ‐19) Patients Who Stay Moderately Ill Versus Patients Who Become Severely Ill

ABSTRACT Background As the disease course of coronavirus disease 2019 (COVID‐19) can change rapidly, clinically relevant prognostic biomarkers could facilitate clinical‐decision making. Prior research has shown that Serum Amyloid A (SAA) might serve as a prognostic biomarker in patients with COVID‐19. The aim of this study was to determine the discriminative ability of SAA, C‐reactive protein (CRP), ferritin, and procalcitonin (PCT) in patients with COVID‐19 to differentiate between those who remain moderately ill from patients who become severely ill within 7 days of hospitalization. Methods Blood samples and disease severity assessment were collected at day 1 (day of hospitalization), 3, 5, and 7 in a Dutch cohort of patients who were hospitalized for COVID‐19. Blood was analyzed for concentrations of SAA, CRP, ferritin, and PCT. Results 133 patients were included in this study. No differences in concentration of SAA, CRP, ferritin, and PCT at time of hospitalization were observed in patients who remained moderately ill compared to patients who progressed to severe COVID‐19 within 7 days of hospitalization. ROC curve analysis revealed that SAA, CRP, ferritin, and PCT failed to discriminate patients who progressed to severe illness from those who remained moderately ill, with areas under the curve (AUC) of 0.461 for SAA, 0.500 for CRP, 0.528 for PCT, and 0.550 for ferritin. Conclusion Our study demonstrates that SAA, CRP, ferritin, and PCT levels at the time of hospitalization failed to discriminate between COVID‐19 patients who remain moderately ill and those who progress to severe disease within 7 days.