A Pilot Study of the Performance Characteristics of the D-dimer in Presumed Sepsis

Abstract

Objectives: To determine if a sensitive D-dimer assay can exclude progression to organ dysfunction, death, and intensive care unit (ICU) admission in patients presenting to the emergency department (ED) with suspected infection, and if increasing levels of D-dimer are predictive of those end points.

Methods: The study took place at two academic EDs, both located in tertiary care hospitals. This was a prospective convenience sample of adult patients presenting with an infective process and at least two of four criteria for the Systemic Inflammatory Response Syndrome. We measured D-dimer levels in the participants and abstracted their records for the end points. Sensitivity and specificity were calculated and receiver operating characteristic analysis was performed to determine if a higher cutoff would have a greater specificity for our end points.

Results: We enrolled 134 patients. Twelve were excluded from analysis (10 for lack of a D-dimer, one for recent surgery, and one for complete loss to follow up). Using the cutoff of 0.4 established by our laboratories as positive, the D-dimer had a sensitivity of 94% (CI95; 76-99) for organ dysfunction in the ED, 93% (72-99) for organ dysfunction at 48 hours, 93% (81-98) for ICU admission, and 100% (63-100) for 30-day mortality. However, at this cutoff, specificity was not statistically significant. Significantly raising the cutoff for a positive resulted in a decrease in sensitivity but improved specificity.

Conclusion: This study was limited by its nonconsecutive patient recruitment and sample size. A normal D-dimer may exclude progression to organ dysfunction, ICU admission, and death and, at higher cutoff levels, could help risk stratify patients presenting to the ED with signs of sepsis.

Figure 1.

Outcomes for all enrolled patients.

Figure 2.

Outcomes for all admitted patients.

Figure 3.

Receiver operator characteristic curve for intensive care unit admission. D-dimer area under the curve 0.79 (95% CI 0.69–0.89) Lactate area under the curve 0.65 (95% CI 0.52–0.78).

Figure 4.

Receiver operator characteristic curve for Organ Dysfunction at 48 hours. D-dimer area under the curve 0.74 (95% CI 0.56–0.92). Lactate area under the curve 0.78 (95% CI 0.63–0.94).

Figure 5.

Receiver operator characteristic curve for 30-days mortality. D-dimer area under the curve 0.72 (95% CI 0.55–0.89). Lactate area under the curve 0.65 (95% CI 0.37–0.74).