Rationale: The diagnosis of ventilator-associated pneumonia (VAP) can be difficult. Soluble triggering receptor expressed on myeloid cell-1 (sTREM-1) has been reported to be elevated in BAL fluid from patients with VAP.

Objective: To evaluate the utility of sTREM-1 in the diagnosis of VAP in BAL fluid and the fluid collected in the expiratory trap from the ventilator, the exhaled ventilator condensate (EVC).

Methods: We prospectively collected BAL fluid and EVC from 23 patients clinically suspected of having VAP. A sensitive enzyme-linked immunosorbent assay was developed to measure sTREM-1. The results derived from this assay were confirmed using an immunoblot technique. The presence of VAP was clinically determined using a modified clinical pulmonary infection score of > 6.

Results: VAP was diagnosed in 14 of 23 patients. sTREM-1 was detected in the EVC from 11 of 14 subjects with VAP, but from only 1 of 9 subjects without VAP, and was significantly higher in the pneumonia patients and when expressed as picograms per milliliter or picograms per microgram protein (p = 0.005, both comparisons). In contrast, sTREM-1 was detected in the BAL fluid of all 14 VAP subjects but also in 8 of 9 subjects with no pneumonia, and did not differ in the VAP subjects compared to the nonpneumonia subjects when expressed as picrograms per milliliter or picograms per microgram protein (p > 0.05 both comparisons).