title: Markers of bacteremia in febrile neutropenic patients with hematological malignancies: procalcitonin and IL-6 are more reliable than C-reactive protein.
abstract: Since neutropenic patients with hematological malignancies are at high risk of contracting life-threatening infections, specific markers of infection are needed in cases of febrile neutropenia. The study presented here assessed serum concentrations of C-reactive protein (CRP), procalcitonin (PCT) and interleukin-6 (IL-6) in samples obtained from 31 febrile neutropenic patients. A total of 53 episodes were evaluated, and 18 of these were associated with positive blood culture results. Procalcitonin and IL-6 concentrations differed significantly between bacteremic and non-bacteremic episodes. Procalcitonin values were 0.22 ng/ml [interquartile range (IR), 0.15-1.9] for patients with pneumonia without bacteremia, 0.22 ng/ml (IR, 0.16-0.55) for patients with fever of unknown origin, 0.2 ng/ml (IR, 0.13-0.57) for patients with non-microbial fever and 1.8 ng/ml (IR, 0.35-5.3) for patients with bacteremia. The differences between bacteremic and non-bacteremic episodes had a P-value of 0.003 using the Mann-Whitney test. For IL-6 the median values were 301 pg/ml (IR, 152-1,879) for patients with pneumonia without bacteremia, 207 pg/ml (IR, 94-445) for patients with fever of unknown origin, 177 pg/ml (IR, 142-208) for patients with non-microbial fever and 942 pg/ml (IR, 181-2,807) for patients with bacteremia. Using the Mann-Whitney test, the differences between bacteremic and non-bacteremic episodes were P=0.006. No differences were found in CRP concentrations. Cutoff levels to distinguish between bacteremic and non-bacteremic episodes were chosen using receiver operating characteristic curves: 0.62 ng/ml for PCT and 297 pg/ml for IL-6. Negative predictive values were 84% for PCT and 70% for IL-6. The results indicate that PCT and IL-6 are more reliable markers than CRP for predicting bacteremia in patients with febrile neutropenia.
authors.affiliation: Medizinische Klinik und Poliklinik I, Universitätsklinikum Bonn, Sigmund Freud Strasse 25, 53105 Bonn, Germany. m.lilienfeld.toal@uni-bonn.de
authors.forename: M
authors.initials: M
authors.lastname: von Lilienfeld-Toal
authors.forename: M P
authors.initials: MP
authors.lastname: Dietrich
authors.forename: A
authors.initials: A
authors.lastname: Glasmacher
authors.forename: L
authors.initials: L
authors.lastname: Lehmann
authors.forename: P
authors.initials: P
authors.lastname: Breig
authors.forename: C
authors.initials: C
authors.lastname: Hahn
authors.forename: I G H
authors.initials: IG
authors.lastname: Schmidt-Wolf
authors.forename: G
authors.initials: G
authors.lastname: Marklein
authors.forename: S
authors.initials: S
authors.lastname: Schroeder
authors.forename: F
authors.initials: F
authors.lastname: Stuber
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016470:Bacteremia / Q000175:diagnosis* / Q000209:etiology; D015415:Biomarkers; D002097:C-Reactive Protein / Q000032:analysis / Q000378:metabolism*; D002116:Calcitonin / Q000032:analysis / Q000378:metabolism*; D015740:Calcitonin Gene-Related Peptide; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005334:Fever / Q000150:complications / Q000175:diagnosis; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis; D019337:Hematologic Neoplasms / Q000150:complications / Q000175:diagnosis; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009503:Neutropenia / Q000150:complications / Q000175:diagnosis; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011498:Protein Precursors / Q000032:analysis / Q000378:metabolism*; D012372:ROC Curve; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; D015850:Interleukin-6; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide