title: Prospective evaluation of automatized PF4/heparin immunoassays HemosIL HIT-ab (PF4-H) for the diagnosis of heparin-induced thrombocytopenia.
abstract: BACKGROUND
  Recently, rapid immunoassays have been developed to allow the detection of antibodies anti-PF4/heparin. In this prospective study, we evaluated the performances of a automatized immunoassay (HemosIL HIT-Ab) in comparison with an ELISA (Zymutest HIA IgG) used for the diagnosis of heparin-induced thrombocytopenia (HIT) in association with the 4T's score.
  
  
  METHODS
  According to the 4T's score, samples with score ≤3 had no further analysis. Two immunological assays Zymutest HIA IgG and HemosIL HIT-Ab were performed in samples with score ≥4. In patients with at least one positive immunological assay or two negative immunological assays but with high-pretest probability (4T's score ≥6), HIT was screened by one functional assay using washed platelets.
  
  
  RESULTS
  The sensitivities of both assays were excellent and comparable (100%). The specificity was 92.3% for ELISA and 91.2% for HemosIL HIT-Ab. The analysis of the operating characteristics showed that both assays have almost identical ROCs (AUROC, 0.9951 and 0.9853, respectively, for ELISA and HemosIL HIT-Ab) and the calculating of the κ coefficient revealed a good agreement (0.67).
  
  
  CONCLUSIONS
  Performance characteristics of the HemosIL HIT-Ab are comparable to the Zymutest HIA IgG. The HemosIL HIT-Ab can be used in association with the 4T's score to rule out HIT.
authors.affiliation: Hemostasis Laboratory, Edouard Herriot Hospital, Lyon, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Jourdy
authors.forename: C
authors.initials: C
authors.lastname: Nougier
authors.forename: L
authors.initials: L
authors.lastname: Rugeri
authors.forename: J C
authors.initials: JC
authors.lastname: Bordet
authors.forename: F
authors.initials: F
authors.lastname: Sobas
authors.forename: C
authors.initials: C
authors.lastname: Negrier
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000906:Antibodies / Q000097:blood / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006493:Heparin / Q000009:adverse effects* / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D010978:Platelet Factor 4 / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013921:Thrombocytopenia / Q000175:diagnosis* / Q000209:etiology*; D055815:Young Adult
chemical_list: D000906:Antibodies; D010978:Platelet Factor 4; D006493:Heparin
keywords: ELISA; HIT antibodies; Heparin-induced thrombocytopenia; immunoassay