Urinary orosomucoid: a novel, early biomarker of sepsis with promising diagnostic performance

Background: In order to help clinical decision making, we investigated the diagnostic and prognostic ability of urinary orosomucoid (u-ORM) as a new sepsis biomarker, and compared its performance to classical inflammatory parameters. Methods: We monitored u-ORM in septic (n = 43) and SIRS (n = 13) patients in a 5-day follow-up study vs. control patients (n = 30). U-ORM was measured by a newly developed turbidimetric assay. U-ORM values were referred to urinary creatinine and expressed as u-ORM/u-CREAT (mg/mmol). Results: Significantly higher (p < 0.001) u-ORM/u-CREAT levels were found in sepsis than in SIRS. Both intensive care unit (ICU) groups showed strongly elevated values compared to controls (p < 0.001). The medians of admission u-ORM/u-CREAT levels were 19.2 in sepsis, 2.1 in SIRS and 0.2 mg/mmol in controls. The area under the receiver operating characteristic curve for distinguishing SIRS from sepsis was found to be 0.954 for u-ORM/u-CREAT, superior to serum ORM and hsCRP. U-ORM levels did not change during the 5-day follow-up and were independent of the severity of sepsis however, we found extremely elevated u-ORM/u-CREAT values in dialyzed septic patients (52.2 mg/mmol as median). Conclusions: The early and relevant increase of u-ORM in sepsis suggests that it might be a promising novel marker of sepsis and could be a valuable part of routine laboratory and clinical practice.