EXPRESS: Reference values for C-reactive protein and procalcitonin at term pregnancy and in the early postnatal period.

Joyce, Caroline; Deasy, Shane; Abu, Hala; Yin Lim, Yoke; O'Shea, Paula; O'Donoghue, Keelin

BACKGROUND Early recognition of sepsis and prompt treatment improves patient outcome. C-reactive protein (CRP) is a sensitive marker for tissue damage and inflammation but Procalcitonin (PCT) has greater specificity for bacterial infection. Limited research exists regarding the use of CRP and PCT at term pregnancy and the immediate postpartum period. AIM This study sought to define reference values for CRP and PCT at term and the early postnatal period. METHODS A prospective cross-sectional study was performed in a university teaching hospital. Venous blood was collected from healthy women (n=196), aged between 19-45 years with an uncomplicated singleton pregnancy, at term (37-40 weeksâ gestation) and on day 1 and day 3 postpartum for the measurement of CRP and PCT. RESULTS The reference population comprised of 189 participants: term pregnancy (n=51), postpartum day 1 vaginal delivery (VD, n=70) and caesarean section (CS, n=38) and day 3 (CS, n=30). The maximum PCT value at term pregnancy was 0.1µg/L. On day 1 postpartum, 90% and 86.8% of PCT results for VD and CS respectively were below the decision-threshold of 0.25 µg/L. The specificity of PCT to rule out infection in the reference population was 91.5%. CONCLUSIONS Reference values for PCT were established in a well-characterised population of healthy pregnant women at term and immediately postpartum. The variability of CRP limits its clinical utility in the assessment of systemic sepsis. Application of the PCT cut-off of 0.25 µg/L in this population will be a valuable adjunct to clinicians ruling out infection in pregnancy and postpartum.