title: European and Mexican vs US diagnostic extracts of Bermuda grass and cat in skin testing.
abstract: BACKGROUND
  Laboratory testing of various diagnostic extracts has shown lower potencies for several European and Mexican extracts relative to the US Food and Drug Administration (FDA) reference (10,000 BAU/mL). Quantitative skin prick testing (QSPT) with Dermatophagoides pteronyssinus extracts have previously shown a similar picture.
  
  
  OBJECTIVE
  To compare European and Mexican Bermuda grass (BG) and cat diagnostic extracts against an FDA-validated extract using QSPT.
  
  
  METHODS
  Six diagnostic BG and cat extracts (1 reference FDA extract, 3 European extracts, 1 imported nonstandardized extract from the United States, and 1 Mexican extract) were tested with quadruplicate QSPT, as a concentrate and as 2 serial 2-fold dilutions, in cat and BG allergic individuals.
  
  
  RESULTS
  BG showed good dose response in wheal size for the concentrate (1:2-1:4 dilutions; steep part of the curve). Cat showed poorer dose response. The Wilcoxon test for linked random samples was used to investigate whether the distribution of the reference differed from each of the test extracts to a statistically significant degree (2-sided asymptotic significance, α = .05). All BG and 2 cat extracts were statistically less potent than the 10,000 BAU/mL US reference. European BG extracts were 7,700, 4,100, and 1,600 BAU/mL, and cat extracts were 12,500, 4,400, and 5,100 BAU/mL.
  
  
  CONCLUSIONS
  The potency of some diagnostic extracts of BG and cat used in Europe, Mexico, and the United States differs, with the US extracts being generally more potent. On the basis of provocation tests, optimal diagnostic concentrations should be determined. Similar comparisons using other manufacturers and therapeutic extracts might be interesting.
authors.affiliation: Hospital Médica Sur, Mexico City, Mexico. marlar1@prodigy.net.mx
authors.forename: Désirée
authors.initials: D
authors.lastname: Larenas-Linnemann
authors.forename: Alfredo Arias
authors.initials: AA
authors.lastname: Cruz
authors.forename: Isabel Rojo
authors.initials: IR
authors.lastname: Gutierrez
authors.forename: Pablo
authors.initials: P
authors.lastname: Rodriguez
authors.forename: Kijawasch
authors.initials: K
authors.lastname: Shah-Hosseini
authors.forename: Alexandra
authors.initials: A
authors.lastname: Michels
authors.forename: Ralph
authors.initials: R
authors.lastname: Mösges
mesh_terms: D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D000818:Animals; D002415:Cats; D031744:Cynodon / Q000737:chemistry / Q000276:immunology*; D004311:Double-Blind Method; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D012221:Rhinitis, Allergic, Perennial / Q000175:diagnosis* / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis* / Q000276:immunology; D012882:Skin Tests / Q000009:adverse effects; D013810:Therapeutic Equivalency; D014481:United States; D055815:Young Adult
chemical_list: D000485:Allergens