The role of CRP, PCT, IL-6 and presepsin in early diagnosis of bacterial infectious complications in paediatric haemato-oncological patients.

Bacterial infection is the most common complication in paediatric oncological patients during cancer treatment. A suitable tool for early prediction of unfavourable course of infection is still needed. We performed a prospective longitudinal observational study to evaluate of the role of serum biomarkers (C-reactive protein, procalcitonin, interleukin-6, presepsin) in the early diagnosis of bacteraemia (gram-negative versus gram-positive) in patients with haematological malignancies. We observed 69 febrile episodes in 33 patients (17 male, 16 female; 1.5-18.9 years, mean 7.31 years, median 5 years). Within this sample, there were 22 cases of positive blood cultures, 16 cases of sepsis, 38 cases of fever with no signs or symptoms of sepsis, and two deaths from infectious complications. All markers tested had good negative predictive value (73% - 93%). CRP was characterized by good specificity for registration bacteraemia (96%, 95% CI: 85% - 99%), but other results were inconclusive. We identified comparably balanced sensitivity (64% - 81%) and specificity (61% - 88%) for interleukin-6 and procalcitonin, and we proved their quality to predict positive blood culture and clinical signs of sepsis as well. Patients with gram-negative bacteraemia had significantly elevated levels of PCT and IL-6 in comparison with a group of patients with gram-positive bacteraemia (p = 0.04 for PCT and p = 0.005 for IL-6). Presepsin was characterized by poor specificity (27%, 95% CI: 15% - 43%) and positive predictive value (24%, 95% CI: 12 - 39%) for predicting bacteraemia, and by better sensitivity (84%, 95% CI: 55% - 98%) and specificity (58%, 95% CI: 42% - 73%) for predicting clinical signs of sepsis.