Combination of C-Reactive Protein and Procalcitonin in Distinguishing Fungal from Bacterial Infections Early in Immunocompromised Children

Invasive fungal infection (IFI) is life-threatening in children with cancer and hematology disorders, especially when diagnosis and treatment are delayed. Conventional beta-D-glucan and galactomannan tests have poor positive predictive values in the diagnosis of IFI in children with cancer. This study aims to access the diagnostic performance of C-reactive protein (CRP) and procalcitonin (PCT) in differentiating IFI from bacterial bloodstream infections in children with malignant and hematology disorders. CRP and PCT levels were measured in samples taken from patients between 12 and 24 h after fever onset, of which 24 and 102 were in the IFI and bacterial groups, respectively. We found that the CRP levels were much higher in the IFI group than the bacterial group (100.57 versus 40.04 mg/L, median, p < 0.001), while the PCT levels remained significantly lower (0.45 versus 1.29 mu g/L, median, p = 0.007). Both CRP and PCT showed significant diagnostic utilities with an area under the curve (AUC) of 0.780 (95% CI, 0.664-0.896, p < 0.001) and 0.731 (95% CI, 0.634-0.828, p < 0.001) when using the cut-off values of 94.93 mg/L and 2.00 mu g/L, respectively. However, the combined biomarker of CRP and PCT yielded a better diagnostic performance with an AUC of 0.934 (95% confidential interval (CI), 0.881-0.987, p < 0.001), which was significantly higher than that of CRP or PCT (both p < 0.001), with a sensitivity of 87.5% and a specificity of 87.3%. Our study demonstrates high levels of CRP combined with low PCT could differentiate IFI from bacterial bloodstream infections in immunocompromised children.