International Normalized Ratio
The International Normalized Ratio (INR) is a "system established by the World Health Organization and the International Committee on Thrombosis and Hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the International Sensitivity Index for the particular test reagent/instrument combination used.[1]
It is a computation based on the prothrombin time (PT) and partial thromboplastin time (PTT).
Point-of-care testing
Point-of-care testing of the INR with a sample of blood obtained by fingerstick may[2] or may not[3] be as reliable as an INR measured by a central laboratory. Clinical practice guidelines by the American College of Chest Physicians state "where possible, we suggest that personnel using POC office-based testing participate in proficiency schemes available through professional or national quality assurance organizations".[4]
References
- ↑ Anonymous (2024), International Normalized Ratio (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Bussey HI, Chiquette E, Bianco TM, Lowder-Bender K, Kraynak MA, Linn WD et al. (1997). "A statistical and clinical evaluation of fingerstick and routine laboratory prothrombin time measurements.". Pharmacotherapy 17 (5): 861-6. PMID 9324174. [e]
- ↑ Poller L, Keown M, Chauhan N, van den Besselaar AM, Tripodi A, Shiach C et al. (2003). "Reliability of international normalised ratios from two point of care test systems: comparison with conventional methods.". BMJ 327 (7405): 30. DOI:10.1136/bmj.327.7405.30. PMID 12842954. PMC PMC164241. Research Blogging.
- ↑ Ansell J, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G et al. (2008). "Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition).". Chest 133 (6 Suppl): 160S-198S. DOI:10.1378/chest.08-0670. PMID 18574265. Research Blogging.