title: Hemoglobin H identification by high-performance liquid chromatography in confirmed hemoglobin H disease.
abstract: BACKGROUND
  Among hemoglobin (Hb) H disease cases diagnosed by DNA testing in our hemoglobinopathy laboratory, we have noted instances of unreported Hb H from high-performance liquid chromatography (HPLC) results of referring laboratories.
  
  
  METHODS
  To characterize these issues, we identified all cases of genotypic Hb H disease diagnosed in our laboratory. HPLC chromatograms were reviewed to determine the presence and retention time of the Hb H peak.
  
  
  RESULTS
  Hemoglobin H was not reported in 24.2% of patients (23 of 95) with genotypic Hb H disease. The characteristic prerun peak of Hb H was present on review of all eight Variant or Variant II β-thalassemia short-program chromatograms. Elevated Hb F (≥3%) was reported in 14 cases. The Hb H peak was found in the Hb F window in 11 dual program cases. The incorrect identification of Hb H as elevated Hb F resulted in two testing referrals for 'δβ-thalassemia'.
  
  
  CONCLUSIONS
  Hemoglobin H may go unreported due to failure to examine for or recognize its peak on Variant or Variant II β-thalassemia short-program chromatograms. Elution of Hb H in the Hb F window resulted in misidentification of Hb H for Hb F and may indicate a Variant II HbA2 /HbA1C program software error. Our findings highlight the need for careful chromatogram inspection and clinical correlation in the diagnosis of Hb H disease.
authors.affiliation: Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
authors.forename: E
authors.initials: E
authors.lastname: Turley
authors.affiliation: Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: McFarlane
authors.affiliation: Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Halchuk
authors.affiliation: Hamilton Regional Laboratory Medicine Program, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Verhovsek
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004909:Erythrocyte Indices; D005260:Female; D005319:Fetal Hemoglobin / Q000737:chemistry; D005838:Genotype; D006447:Hemoglobin H / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult; D055542:alpha-Globins / Q000737:chemistry / Q000235:genetics; D017085:alpha-Thalassemia / Q000097:blood / Q000175:diagnosis* / Q000235:genetics
chemical_list: D055542:alpha-Globins; D005319:Fetal Hemoglobin; D006447:Hemoglobin H
keywords: Hemoglobin H disease; hemoglobinopathy; high-performance liquid chromatography; laboratory practice; thalassemia