title: Usefulness of UniCAP-Tryptase fluoroimmunoassay in the diagnosis of anaphylaxis.
abstract: BACKGROUND
  Serum tryptase level measured by RIA is the main in vitro tool to confirm the diagnosis of anaphylaxis.
  
  
  METHODS
  Serum tryptase levels were determined by UniCAP-Tryptase fluoroimmunoassay (Pharmacia & Upjohn, Uppsala, Sweden), in 30 consecutive patients who presented at the emergency room with a clinical allergic reaction of less than 6-h duration to assess the value of this method in the diagnosis of anaphylaxis. Anaphylaxis was established by clinical criteria and by immunoallergic study. Baseline tryptase levels were determined 1 month later in 21 patients. The receiver operating curve (ROC) was used to establish the best cutoff point of tryptase levels to confirm the diagnosis of anaphylaxis.
  
  
  RESULTS
  Seventeen patients were diagnosed with anaphylaxis. In this group, tryptase levels were higher than in the nonanaphylaxis group, composed mostly of patients with urticaria or angioedema (P<0.001). ROC established the best cutoff of tryptase levels at 8.23 ng/ml with a 94.12% sensitivity and 92.31% specificity, whereas the 13.5 ng/ml cutoff recommended by the manufacturers showed 35.29% sensitivity and 92.31% specificity. The reaction-tryptase/baseline-tryptase ratio was 2.85 in the anaphylaxis group and 1.29 in the nonanaphylaxis group.
  
  
  CONCLUSIONS
  Serum tryptase levels of >8.23 ng/ml by UniCAP-Tryptase fluoroimmunoassay identify anaphylaxis in patients with symptoms of less than 6-h duration. The usefulness of this determination is higher if baseline tryptase levels are available.
authors.affiliation: Department of Internal Medicine, Hospital Joan XXIII, Universitat Rovira i Virgili, Tarragona, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Enrique
authors.forename: P
authors.initials: P
authors.lastname: García-Ortega
authors.forename: O
authors.initials: O
authors.lastname: Sotorra
authors.forename: P
authors.initials: P
authors.lastname: Gaig
authors.forename: C
authors.initials: C
authors.lastname: Richart
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000707:Anaphylaxis / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D015415:Biomarkers; D053818:Chymases; D005069:Evaluation Studies as Topic; D005260:Female; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012697:Serine Endopeptidases / Q000032:analysis* / Q000097:blood; D053802:Tryptases
chemical_list: D015415:Biomarkers; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; D053802:Tryptases