Combining qSOFA criteria with initial lactate levels: Improved screening of septic patients for critical illness

Objective: To determine if the addition of lactate to Quick Sequential Organ Failure Assessment (qSOFA) scoring improves emergency department (ED) screening of septic patients for critical illness. Methods: This was a multicenter retrospective cohort study of consecutive adult patients admitted to the hospital from the ED with infectious disease-related illnesses. We recorded qSOFA criteria and initial lactate levels in the first 6 h of ED stay. Our primary outcome was a composite of hospital death, vasopressor use, and intensive care unit stay ≤72 h of presentation. Diagnostic test characteristics were determined for: 1) lactate levels ≥2 and ≥4; 2) qSOFA scores ≥1, ≥2, and =3; and 3) combinations of these. Results: Of 3743 patients, 2584 had a lactate drawn ≤6 h of ED stay and 18% met the primary outcome. The qSOFA scores were ≥1, ≥2, and =3 in 59.2%, 22.0%, and 5.3% of patients, respectively, and 34.4% had a lactate level ≥2 and 7.9% had a lactate level ≥4. The combination of qSOFA ≥1 OR Lactate ≥2 had the highest sensitivity, 94.0% (95% CI: 91.3–95.9). Conclusions: The combination of qSOFA ≥1 OR Lactate ≥2 provides substantially improved sensitivity for the screening of critical illness compared to isolated lactate and qSOFA thresholds.