C-reactive protein to transthyretin ratio for the early diagnosis and follow-up of postoperative infection

The clinical usefulness of Creactive protein (CRP) and of transthyretin (TTR) for the early diagnosis and follow up of infection after an open fracture was prospectively investigated (cohort A). It was complemented by a retrospective study of trauma patients admitted to an intensive care unit (cohort B). Serial determinations of serum CRP and TTR concentrations were first performed in uninfected patients from cohort A to define reference profile during the early postoperative period. It showed a concomitant increase in CRP and decrease in TTR concentrations, followed by progressive return to initial values in patients free from bacterial infection. Variations of the CRP/TTR ratio were analyzed. Recovery phase was defined by an exponential evolution of the two plasma proteins and of their ratio value. The CRP and TTR concentrations were independent of sex and severity of the trauma. In the case of postoperative infection, patients of cohort A revealed amplified CRP and TTR responses usually preceding the occurrence of clinical signs. During successful antibiotic therapy, their recovery response became superimposable to that of the reference group. The same profiles were recorded in cohort B patients admitted with lower limb fractures or various types of trauma. This suggests that observations made on cohort A can be extrapolated to other trauma patients. We recommend that serial measurements of CRP and TTR and of their ratio should be performed every 2 days to appropriately followup these patients.