title: There are considerable drawbacks to oral anticoagulant for monitoring patients at home which should lead family physicians to discuss alternative or enhanced solutions: a cross-sectional study.
abstract: BACKGROUND
  INR (International Normalized Ratio) is the biological reference test for the monitoring of vitamin K antagonist (VKA) therapy. Overdosage of VKAs causes about 17,000 hospitalizations and 5,000 deaths each year in France. To avoid these complications, monitoring and blood sampling conditions must be rigorous. In France, more than half of INRs are carried out at home. The aim was to determine blood-sampling conditions at home, transit time and the quality of the laboratory reagents used.
  
  
  METHODS
  Questionnaire-based, descriptive epidemiological cross-sectional prevalence study involving home care nurses, family physicians (FPs) and clinical laboratories.
  
  
  METHODS
  Brittany, France, 2008. Study of the pre-analytical phase of INRs sampled at home and its influence on INR results.
  
  
  RESULTS
  The study included 291 FPs, 249 home care nurses, and 49 laboratories. 32.5% of reported INRs were outside the therapeutic range. Samples were drawn into unsuitable tubes in 5.5% of cases and delivered in a chilled condition in 9% of cases. In urban areas 50% of the tubes took more than 2 hours to reach the laboratory compared with 71% from rural areas. The average International Sensitivity Index (ISI) of the thromboplastin was 1.62. The INRs provided by the laboratories were not analyzable in 64.7% of cases where blood samples had been taken at home.
  
  
  CONCLUSIONS
  Blood sample quality, transit time and the reagents used are currently inadequate. The majority of INRs taken at home are not reliable. FPs should consider these drawbacks in comparison with alternative solutions to increase patient safety.
authors.affiliation: Département de médecine générale - UFR Brest, Rue Camille Desmoulins, 29200 Brest, France. lereste@univ-brest.fr.
authors.forename: Jean Yves
authors.initials: JY
authors.lastname: Le Reste
authors.forename: Benoit
authors.initials: B
authors.lastname: Chiron
authors.forename: Bernard
authors.initials: B
authors.lastname: Le Floch
authors.forename: Patrice
authors.initials: P
authors.lastname: Nabbe
authors.forename: Marie
authors.initials: M
authors.lastname: Barrais
authors.forename: Jacques
authors.initials: J
authors.lastname: Mansourati
authors.forename: Sébastien
authors.initials: S
authors.lastname: Cadier
authors.forename: Pierre
authors.initials: P
authors.lastname: Barraine
authors.forename: Claire
authors.initials: C
authors.lastname: Lietard
mesh_terms: D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage* / Q000097:blood*; D003430:Cross-Sectional Studies; D005602:France / Q000453:epidemiology; D006699:Home Care Services / Q000592:standards*; D006801:Humans; D019934:International Normalized Ratio / Q000379:methods / Q000592:standards; D018670:Monitoring, Ambulatory / Q000379:methods / Q000592:standards*; D064691:Nurses, Community Health / Q000592:standards; D010821:Physicians, Family / Q000592:standards*; D011795:Surveys and Questionnaires
chemical_list: D000925:Anticoagulants
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