title: Pitfalls in the diagnosis of latex allergy.
abstract: BACKGROUND
  Screening patients for latex allergy prior to surgery is an important but intensive procedure. The appropriate testing strategy for diagnosing latex (Hevea brasiliensis) allergy involves in-vitro specific IgE or skin prick testing. The sensitivity and specificity of both tests are influenced by patient-specific factors or manufacturing processes that alter the clinically relevant allergens in skin testing solutions.
  
  
  METHODS
  Total IgE and latex-specific IgE testing was introduced as a screening test. Skin prick testing was done on patients with a high probability of latex allergy and negative specific IgE with total IgE <100 kU/L. SDS-PAGE was done on the non-ammoniated latex (NAL) and newly introduced ammoniated latex (AL) reagents for the clinically relevant allergens.
  
  
  RESULTS
  51 patients had a total IgE <100 (range, 2.8-99.0 kU/L), and 10% had a positive skin test. 60% of positive skin tests would have been missed with lower total IgE cut-offs of 50 kU/L (6% of referrals). SDS-PAGE of the NAL solution showed 3 prominent bands with molecular weights of approximately 20, 24 and 42 kDa that correlated with Hev b 6, Hev b 3 and Hev b 7/13, respectively. In contrast, the AL solution showed 3 very faint higher molecular weights bands that did not correlate with clinically relevant antigens.
  
  
  CONCLUSIONS
  Increasing the cut-off value of total IgE for allergen-specific IgE testing increased the sensitivity of the specific IgE test. The NAL reagent had a greater number of clinically significant allergens at higher concentrations than AL, which may have implications for the clinical sensitivity of the newer AL reagent.
authors.affiliation: Path Links Immunology, Scunthorpe General Hospital, Scunthorpe, United Kingdom; Department of Immunology, Hull Royal Infirmary, University of Hull, Hull, United Kingdom. Electronic address: sujoykhan@gmail.com.
authors.forename: Sujoy
authors.initials: S
authors.lastname: Khan
authors.affiliation: Department of Immunology, Hull Royal Infirmary, University of Hull, Hull, United Kingdom; Post graduate Medical Institute, University of Hull, Hull, United Kingdom.
authors.forename: Steve
authors.initials: S
authors.lastname: Holding
authors.affiliation: Department of Immunology, Hull Royal Infirmary, University of Hull, Hull, United Kingdom; Hull York Medical School, University of Hull, Hull, United Kingdom.
authors.forename: Philip
authors.initials: P
authors.lastname: Doré
authors.affiliation: Path Links Immunology, Scunthorpe General Hospital, Scunthorpe, United Kingdom; Hull York Medical School, University of Hull, Hull, United Kingdom.
authors.forename: Carrock
authors.initials: C
authors.lastname: Sewell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000276:immunology / Q000378:metabolism / Q000627:therapeutic use; D052179:Antigens, Plant / Q000276:immunology / Q000378:metabolism / Q000627:therapeutic use; D003951:Diagnostic Errors / Q000517:prevention & control; D028482:Hevea; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism*; D007167:Immunotherapy; D020315:Latex Hypersensitivity / Q000175:diagnosis* / Q000276:immunology / Q000628:therapy; D008875:Middle Aged; D010940:Plant Proteins / Q000276:immunology / Q000378:metabolism / Q000627:therapeutic use; D012015:Reference Standards; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000592:standards; D012882:Skin Tests
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C097982:Hev b 6.01 protein, Hevea brasiliensis; D010940:Plant Proteins; C113002:allergen Hev b 7; C061477:REF protein, Hevea brasiliensis; D007073:Immunoglobulin E