title: Hemoglobin A1c: a reliable and accurate test for diabetes care? A prospective study in Mexico.
abstract: OBJECTIVE
  To compare the concordance correlation coefficient for HbA1c results in an in-field experience.
  
  
  METHODS
  A prospective study in Monterrey, Mexico from April to August 2012 was conducted to evaluate the day-to-day clinical situation when measuring HbA1c. Blood samples from 38 consecutive patients were sent to seven local laboratories and one international reference laboratory.
  
  
  RESULTS
  Poor concordance was found in 4 out of 7 laboratories, moderate in 2 out of 7, and significant in just one. HbA1c values from three laboratories fluctuated more than 1% above or below the reference laboratory in more than 30% of cases, and more than 2% in 10%-20% of subjects.
  
  
  CONCLUSIONS
  Standardized HbA1c measurement has not occurred worldwide. Physicians should be aware of this issue and be cautious of HbA1c guidelines on diabetes diagnosis or management until proper standardization programs are implemented.
authors.affiliation: Servicio de Endocrinología, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: José Gerardo
authors.initials: JG
authors.lastname: González-González
authors.affiliation: Servicio de Medicina Interna, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: René
authors.initials: R
authors.lastname: Rodríguez-Gutiérrez
authors.affiliation: Servicio de Endocrinología, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: Fernando Javier
authors.initials: FJ
authors.lastname: Lavalle-González
authors.affiliation: Servicio de Endocrinología, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: Arnulfo
authors.initials: A
authors.lastname: González-Cantú
authors.affiliation: Servicio de Endocrinología, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: Héctor Eloy
authors.initials: HE
authors.lastname: Taméz-Pérez
authors.affiliation: Servicio de Medicina Interna, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: Gerardo
authors.initials: G
authors.lastname: González-Saldívar
authors.affiliation: Servicio de Endocrinología, Hospital Universitario Dr. José E. González, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México.
authors.forename: Jesús Zacarías
authors.initials: JZ
authors.lastname: Villarreal-Pérez
mesh_terms: D000328:Adult; D000368:Aged; D003920:Diabetes Mellitus / Q000097:blood* / Q000628:therapy*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis*; D006403:Hematologic Tests; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D006442:Glycated Hemoglobin