The sensitivity of neutrophil CD64 expression as a biomarker of bacterial infection is low in critically ill patients
- 584 Downloads
CD64 expression on the surface of neutrophils has recently been proposed as an early marker of bacterial infection. The goal of this study was to determine whether the CD64 index allows differentiation of bacterial sepsis from viral and fungal sepsis and other inflammatory states in a critical-care setting.
This was an observational prospective study conducted in a medical ICU of a university hospital. All patients admitted between September 2009 and March 2010 with at least two criteria for systemic inflammatory response syndrome (SIRS) were eligible for inclusion. Upon admission, hematological exams were conducted by flow cytometry, allowing quantification of CD64 expression (Leuko64™ kit, Trillium Diagnostics LLC, USA). ROC curve analysis was performed to evaluate the utility of the CD64 index in the diagnosis of bacterial infection. Patients with suspected infection were excluded when infection could not be microbiologically confirmed.
Our study included 293 patients with a SAPS II score of 45 (31–59). Bacterial infection was found in 148 patients and SIRS or non-bacterial infection was documented in 145 patients. A CD64 index greater than 2.2 predicted bacterial infection with a sensitivity and specificity of 63% (55–71%) and 89% (83–94%), respectively. The area under the ROC curve was 0.8 (0.75–0.84). Positive and negative likelihood ratios were 5.7 (5.0–6.5) and 0.4 (0.3–0.7), respectively.
The CD64 index is specific for bacterial infection among ICU patients. As a result of its weak sensitivity, the CD64 index may not be practically recommended, but it may be useful in combination with a more sensitive biological marker.
KeywordsNeutrophil CD64 Sepsis Critically ill patients Bacterial infection Diagnostic accuracy SIRS
The authors thank BH Davis (Trillium Diagnostics, Brewer, ME, USA) for supplying reagents.
Conflicts of interest
- 2.Kumar A, Roberts D, Wood KE, Light B, Parrillo JE, Sharma S, Suppes R, Feinstein D, Zanotti S, Taiberg L, Gurka D, Cheang M (2006) Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med 34:1589–1596PubMedCrossRefGoogle Scholar
- 10.Groselj-Grenc M, Ihan A, Pavcnik-Arnol M, Kopitar AN, Gmeiner-Stopar T, Derganc M (2009) Neutrophil and monocyte CD64 indexes, lipopolysaccharide-binding protein, procalcitonin and C-reactive protein in sepsis of critically ill neonates and children. Intensive Care Med 35:1950–1958PubMedCrossRefGoogle Scholar
- 19.Gamez-Diaz LY, Enriquez LE, Matute JD, Velasquez S, Gomez ID, Toro F, Ospina S, Bedoya V, Arango CM, Valencia ML, De La Rosa G, Gomez CI, Garcia A, Patino PJ, Jaimes FA (2011) Diagnostic accuracy of HMGB-1, sTREM-1, and CD64 as markers of sepsis in patients recently admitted to the emergency department. Acad Emerg Med 18:807–815PubMedCrossRefGoogle Scholar
- 21.Livaditi O, Kotanidou A, Psarra A, Dimopoulou I, Sotiropoulou C, Augustatou K, Papasteriades C, Armaganidis A, Roussos C, Orfanos SE, Douzinas EE (2006) Neutrophil CD64 expression and serum IL-8: sensitive early markers of severity and outcome in sepsis. Cytokine 36:283–290PubMedCrossRefGoogle Scholar