Procalcitonin for accurate detection of infection in haemodialysis

Background. Infection results in considerable morbidity and mortality in haemodialysis patients. Diagnosis of infection can be difficult because currently applied laboratory parameters may be non-specifically altered due to uraemia or haemodialysis (HD). This study investigated the diagnostic value and kinetics of serum procalcitonin (PCT), a low-molecular-weight protein, in patients receiving intermittent HD. Methods. Sixty-eight patients receiving intermittent HD for end-stage renal disease (n = 48) or acute renal failure (n=20) were prospectively studied, 47 treated with high-flux and 21 with low-flux membranes. Of 36 patients with severe infections or sepsis, 27 were treated with high-flux and nine with low-flux membranes. WBC, serum PCT and C-reactive protein (CRP) concentrations were measured immediately before HD, and PCT repeatedly during the following 48 h. Results. When determined immediately before HD, PCT demonstrated a sensitivity of 89%, a specificity of 81%, and positive and negative predictive values of 84 and 87%, indicating severe infection or sepsis. These levels were higher than the respective values for CRP (89, 48, 68 and 78%) and WBC (58, 75, 71 and 59%). After 4 h of HD with high-flux membranes, PCT decreased significantly to 83 ± 25% and did not return to predialysis concentrations before 48 h. This decrease in serum PCT resulted in markedly reduced sensitivity (65%) and negative predictive value (54%). In contrast, no marked change in PCT concentration occurred during or after HD with low-flux membranes. Conclusion. Serum PCT is an accurate indicator of severe infection and sepsis in patients receiving intermittent HD. High-flux membranes substantially decrease PCT. When utilizing high flux membranes, serum PCT concentrations should be determined prior to the start of HD.