title: Usefulness and limitations of sequential serum tryptase for the diagnosis of anaphylaxis in 102 patients.
abstract: BACKGROUND
  The diagnosis of anaphylaxis is based on clinical history since no reliable biological marker is currently available to confirm the diagnosis.
  
  
  OBJECTIVE
  It was the aim of this study to determine sequential serum tryptase concentrations during anaphylaxis and to evaluate its potential as a diagnostic marker.
  
  
  METHODS
  We performed a prospective study including patients with acute anaphylaxis (according to the National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network criteria) attending the emergency department. Demographic characteristics, anaphylactic triggers, specific risk factors, clinical characteristics and management of anaphylaxis were recorded. Serum tryptase was measured at 1-2 h (T1), 4-6 h (T2) and 12-24 h (T3) following onset of the episode and at basal conditions (TB).
  
  
  RESULTS
  A total of 102 patients were included (63 females, mean age 47.4 ± 19.1 years). Tryptase concentration at T1 (19.3 ± 15.4 µg/l) was significantly higher than at T2, T3 and TB (all <11.4 µg/l; p < 0.0001). Importantly, tryptase was not raised in 36.3% of cases; furthermore, in 60.6% of these patients, no changes were observed in tryptase levels comparing T1 and TB (ΔT1-TB = 0). Tryptase was more frequently elevated in more severe anaphylaxis (p < 0.0001) and positively correlated with the grades of severity (p < 0.001, r = 0.49). Anaphylaxis was more severe and tryptase concentration higher when the causative agent was a drug compared to food, both at T1 (p = 0.045) and at TB (p = 0.019). Age and coronary risk factors were associated with more severe anaphylaxis (p = 0.001).
  
  
  CONCLUSIONS
  Tryptase is a biomarker related to the severity of anaphylaxis. However, since its concentration remains unaltered in a considerable number of patients during acute anaphylaxis, there is a need for more reliable diagnostic biological tests.
authors.affiliation: Allergy Section, Internal Medicine Department, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain. annasala7@gmail.com
authors.forename: Anna
authors.initials: A
authors.lastname: Sala-Cunill
authors.forename: Victoria
authors.initials: V
authors.lastname: Cardona
authors.forename: Moises
authors.initials: M
authors.lastname: Labrador-Horrillo
authors.forename: Olga
authors.initials: O
authors.lastname: Luengo
authors.forename: Olga
authors.initials: O
authors.lastname: Esteso
authors.forename: Teresa
authors.initials: T
authors.lastname: Garriga
authors.forename: Maria
authors.initials: M
authors.lastname: Vicario
authors.forename: Mar
authors.initials: M
authors.lastname: Guilarte
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000707:Anaphylaxis / Q000097:blood* / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053802:Tryptases / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D053802:Tryptases