Thanks to Vadim Kostousov for his comments appended to the September 28, 2013 post, Accuracy of an INR of 10.0. Here are the guidelines from the latest edition of the ACCP guidelines Chest 2012 Exec Summary:
9.1 Vitamin K for Patients Taking VKAs With High INRs Without Bleeding
(a) For patients taking VKAs with INRs between 4.5 and 10 and with no evidence of bleeding, we suggest against the routine use of vitamin K (Grade 2B).
(b) For patients taking VKAs with INRs greater than 10.0 and with no evidence of bleeding, we suggest that oral vitamin K be administered (Grade 2C).
9.2 Clinical Prediction Rules for Bleeding While Taking VKA: For patients initiating VKA therapy, we suggest against the routine use of clinical prediction rules for bleeding as the sole criterion to withhold VKA therapy (Grade 2C).
9.3 Treatment of Anticoagulant-Related Bleeding: For patients with VKA-associated major bleeding, we suggest rapid reversal of anticoagulation with four-factor prothrombin complex concentrate rather than with plasma. (Grade 2C). We suggest the additional use of vitamin K 5 to 10 mg administered by slow IV injection rather than reversal with coagulation factors alone (Grade 2C).
These guidelines are relatively unchanged from earlier ACCP guidelines, and they rest on the assumption that an INR of 10.0 achieves statistical and clinical validity. Given ACCP is regarded as a national guideline, we are expected to be able to report an INR of 10.0, however given the data in the McGlasson article, we know there is really no analytical difference between a 5.0 and 10.0. I invite further comments.