Is plasma cell-free DNA really a useful marker for diagnosis and treatment of trauma patients?

INTRODUCTION: Plasma cell-free DNA (cfDNA) of trauma patients has been widely investigated, but it has not been resolved whether cfDNA can be used as a non-invasive, rapid and sensitive marker of injury. Here we evaluated serum cfDNA in patients after injury and assessed the relationship between cfDNA levels and clinical prognosis.
METHODS: Fifty-six trauma patients formed three groups (minor, moderate and severe) according to Injury Severity Score (ISS), 33 of these cases were also divided according to microbiological and clinical evidence of infection. Plasma cfDNA and other indices were measured 1-6h, 24-36 h and 60-90 h after injury.
RESULTS: The severe and moderate injury groups showed significantly higher positive percentage cfDNA than in the control (p<0.001, p=0.004). Positive plasma cfDNA samples were higher 1-6 h after injury than 24-48 h and 60-90 h, and the mean plasma cfDNA concentrations at 60-90 h were higher than that at the earlier two time points but not significantly. The ISS of the infected group was significantly higher than in the non-infected group (p=0.02). cfDNA was found in 48.5% penetrating trauma samples, significantly higher than that in blunt injury (17.4%) (p=0.024).
CONCLUSIONS: Plasma cfDNA is a potential marker for trauma prognosis especially death, after severe injury, but its sensitivity presents limitations for clinical use. No evidence was found to relate plasma cfDNA to infection. Circulating cfDNA seems to be connected with injury type and mode, open wounds and surgical operations, which may be the primary reasons for plasma cfDNA increase.