title: An enzyme linked immunosorbent assay (ELISA) for the determination of the human haptoglobin phenotype.
abstract: BACKGROUND
  Haptoglobin (Hp) is an abundant serum protein which binds extracorpuscular hemoglobin (Hb). Two alleles exist in humans for the Hp gene, denoted 1 and 2. Diabetic individuals with the Hp 2-2 genotype are at increased risk of developing vascular complications including heart attack, stroke, and kidney disease. Recent evidence shows that treatment with vitamin E can reduce the risk of diabetic vascular complications by as much as 50% in Hp 2-2 individuals. We sought to develop a rapid and accurate test for Hp phenotype (which is 100% concordant with the three major Hp genotypes) to facilitate widespread diagnostic testing as well as prospective clinical trials.
  
  
  METHODS
  A monoclonal antibody raised against human Hp was shown to distinguish between the three Hp phenotypes in an enzyme linked immunosorbent assay (ELISA). Hp phenotypes obtained in over 8000 patient samples using this ELISA method were compared with those obtained by polyacrylamide gel electrophoresis or the TaqMan PCR method.
  
  
  RESULTS
  Our analysis showed that the sensitivity and specificity of the ELISA test for Hp 2-2 phenotype is 99.0% and 98.1%, respectively. The positive predictive value and the negative predictive value for Hp 2-2 phenotype is 97.5% and 99.3%, respectively. Similar results were obtained for Hp 2-1 and Hp 1-1 phenotypes. In addition, the ELISA was determined to be more sensitive and specific than the TaqMan method.
  
  
  CONCLUSIONS
  The Hp ELISA represents a user-friendly, rapid and highly accurate diagnostic tool for determining Hp phenotypes. This test will greatly facilitate the typing of thousands of samples in ongoing clinical studies.
authors.affiliation: Technion-Institute of Technology, The Ruth and Bruce Rappaport Faculty of Medicine, Haifa, Israel.
authors.forename: Nina S
authors.initials: NS
authors.lastname: Levy
authors.forename: Moshe
authors.initials: M
authors.lastname: Vardi
authors.forename: Shany
authors.initials: S
authors.lastname: Blum
authors.forename: Rachel
authors.initials: R
authors.lastname: Miller-Lotan
authors.forename: Yefim
authors.initials: Y
authors.lastname: Afinbinder
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Cleary
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Paterson
authors.forename: Bhupinder
authors.initials: B
authors.lastname: Bharaj
authors.forename: Janet K
authors.initials: JK
authors.lastname: Snell-Bergeon
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Rewers
authors.forename: Orit
authors.initials: O
authors.lastname: Lache
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Levy
mesh_terms: D000483:Alleles; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006242:Haptoglobins / Q000235:genetics* / Q000276:immunology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D010641:Phenotype; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D006242:Haptoglobins