title: What should be the optimal cut-off of serum 1,3-β-D-glucan for the detection of invasive pulmonary aspergillosis in patients with haematological malignancies?
abstract: BACKGROUND
  The detection of 1,3-β-d-glucan (BDG), a cell wall component of several medically important fungi, is a promising tool for the diagnosis of invasive pulmonary aspergillosis. The aim of this study was to evaluate the diagnostic accuracy of the BDG test in invasive pulmonary aspergillosis (IPA) by focusing on the optimal cut-off value.
  
  
  METHODS
  The records of the Infection Control Committee were reviewed to identify patients with haematological malignancies and stem cell transplantation who had at least 1 BDG (Fungitell kit) measurement during the period January 2008 through April 2011. The European Organization for Research and Treatment of Cancer and the Mycoses Study Group (EORTC/MSG) criteria (independent of BDG results) were used to categorize the patients with IPA. Patients with possible IPA were not included in the study.
  
  
  RESULTS
  A total of 128 patients (50 with proven or probable IPA) were included in the study. At the manufacturer's recommended cut-off value of 80 pg/ml, the sensitivity of BDG was 66% (95% CI 51.2-78.7), specificity 75.6% (95% CI 64.6-84.5), positive predictive value (PPV) 63.4%, and negative predictive value (NPV) 77.6%. A receiver operating characteristic (ROC) curve was constructed to define the optimum serum BDG cut-off for the diagnosis of IPA. At a cut-off value of 181 pg/ml, the sensitivity was 52% (95% CI 37.4-66.3), specificity 94.8% (95% CI 87.4-98.6), PPV 86.7%, and NPV 75.5%.
  
  
  CONCLUSIONS
  Although higher cut-off levels increased the specificity of the BDG test, sensitivity decreased to an unacceptable level; the commercially recommended cut-off value appears to be appropriate for screening purposes.
authors.affiliation: Department of Infectious Diseases, Faculty of Medicine, Erciyes University, Kayseri, Turkey. gokhanmetan@gmail.com
authors.forename: Gökhan
authors.initials: G
authors.lastname: Metan
authors.forename: A Nedret
authors.initials: AN
authors.lastname: Koç
authors.forename: Altay
authors.initials: A
authors.lastname: Atalay
authors.forename: Leyla Gül
authors.initials: LG
authors.lastname: Kaynar
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ozturk
authors.forename: Emine
authors.initials: E
authors.lastname: Alp
authors.forename: Bülent
authors.initials: B
authors.lastname: Eser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000946:Antigens, Fungal / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D019337:Hematologic Neoplasms / Q000150:complications*; D006801:Humans; D007223:Infant; D055744:Invasive Pulmonary Aspergillosis / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011509:Proteoglycans; D012372:ROC Curve; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012680:Sensitivity and Specificity; D055815:Young Adult; D047071:beta-Glucans / Q000097:blood* / Q000592:standards*
chemical_list: D000946:Antigens, Fungal; D011509:Proteoglycans; D011933:Reagent Kits, Diagnostic; D047071:beta-Glucans; C010770:polysaccharide-K