Lactate Testing in Suspected Sepsis: Trends and Predictors of Failure to Measure Levels

Objectives: Serum lactate monitoring is central to risk stratification and management of sepsis and is now part of a potential quality measure. We examined 11-year trends in lactate testing and predictors of failure to measure lactates in patients with severe sepsis. Design: Retrospective cohort study. Setting: Two U.S. academic hospitals. Patients: Adult patients admitted from 2003 to 2013. Interventions: Annual rates of lactate measurement were assessed in patients who had blood cultures ordered and patients with severe sepsis, as defined by concomitant International Classification of Diseases, Ninth Revision codes for infection and organ dysfunction. The approximate time of suspected sepsis was determined by the first blood culture order with concurrent antibiotic initiation. Multivariate analysis was performed to identify predictors of failure to measure lactates in severe sepsis cases in 2013. Measurements and Main Results: Among hospitalizations with blood culture orders, rates of lactate measurement increased from 11% in 2003 to 48% in 2013 (p < 0.001 for linear trend). Rates of repeat lactate measurement within 6 hours after lactate levels greater than or equal to 4.0 mmol/L increased from 23% to 69% (p < 0.001). Patients were progressively less likely to be on vasopressors at the time of first lactate measurement (49% in 2003 vs 21% in 2013; p < 0.001). Despite these trends, lactates were measured at the time of suspected sepsis in only 65% of patients with severe sepsis in 2013. On multivariate analysis, hospital-onset sepsis and hospitalization on a nonmedical service were significant predictors of failure to measure lactates (adjusted odds ratio, 7.56; 95% CI, 6.31-9.06 and adjusted odds ratio, 2.08; 95% CI, 1.76-2.24, respectively). Conclusions: Lactate testing has increased dramatically over time and is being extended to patients without overt shock. However, rates of serial lactate testing are still suboptimal, and lactates are not being measured in many patients with severe sepsis. Hospital-onset sepsis and nonmedical units may be high-yield targets for quality improvement initiatives.