title: The diagnostic value of basophil activation test in patients with an immediate hypersensitivity reaction to radiocontrast media.
abstract: BACKGROUND
  No available test diagnoses allergic reactions to radiocontrast media (RCM). The basophil activation test (BAT) has been introduced for the diagnosis of both immunoglobulin (Ig) E and non-IgE-dependent mast cell degranulation, but its value to diagnose immediate RCM reactions is still unknown.
  
  
  OBJECTIVE
  This study aims to evaluate the diagnostic value of BAT in immediate RCM hypersensitivity.
  
  
  METHODS
  The BATs were performed in 26 patients with immediate RCM reactions and in 43 specimens from healthy volunteers. The sample's whole blood was incubated with the responsible RCM and % activated (CD63+/CCR3+) basophils were analyzed by flow cytometry. Receiver operating characteristics (ROC) curve analysis was performed to calculate the optimal cutoff value of activated basophils to diagnose patients with RCM hypersensitivity.
  
  
  RESULTS
  The incubation of blood with RCM yielded significantly higher activated basophil percentages in patients with a history of immediate RCM reactions than in normal controls with both 1:100 and 1:10 dilutions (13.11% vs. 2.71%, P value = .01; and 19.23% vs. 3.73%, P = .001, respectively). Both % activated basophils and stimulation index (SI) had acceptable discrimination powers to diagnose RCM hypersensitivity. The area under the curve was 0.79 (95% CI 0.67-0.91, P = .000) by using SI as the diagnostic criteria with 1:100 dilution of RCM. The specificity of the test ranged from 88.4% to 100%.
  
  
  CONCLUSIONS
  Our study demonstrated the potential of BAT as a diagnostic tool for an immediate RCM hypersensitivity, particularly as a confirmation test. Further studies are required to confirm the test accuracy and identify a patient's predisposing factors.
authors.affiliation: Medical Microbiology, Interdisciplinary Program, Graduate School Chulalongkorn University, Bangkok, Thailand.
authors.forename: Panwas
authors.initials: P
authors.lastname: Pinnobphun
authors.forename: Supranee
authors.initials: S
authors.lastname: Buranapraditkun
authors.forename: Thatchai
authors.initials: T
authors.lastname: Kampitak
authors.forename: Nattiya
authors.initials: N
authors.lastname: Hirankarn
authors.forename: Jettanong
authors.initials: J
authors.lastname: Klaewsongkram
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D015549:Basophil Degranulation Test; D001491:Basophils / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D001769:Blood / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D003287:Contrast Media / Q000009:adverse effects* / Q000494:pharmacology; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D005260:Female; D006636:Histamine Release / Q000187:drug effects / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D017455:Receptors, IgE / Q000276:immunology; D012882:Skin Tests
chemical_list: D000911:Antibodies, Monoclonal; D003287:Contrast Media; D017455:Receptors, IgE