OBJECTIVES:  Measures used to make clinical decisions are assessed by quality assurance (QA) programs.  Our group’s research suggests standard QA analyses can fail to provide relevant clinical information and may be misleading.  We compared a novel clinically-based QA analysis to previously conducted standard QA analysis of INR measures by point-of-care (POC) devices in our anticoagulation clinics. METHODS: Previously analyzed QA data, collected January, 2006 through June, 2008 were obtained.   Two INR samples were obtained from each patient at the same anticoagulation clinic visit: one venous sample analyzed by our core laboratory (considered the reference measure) and one fingerstick analyzed by the Hemochron POC device.  Consistent with published FDA recommendations, the previous standard QA analysis included linear regression, correlation and Bland Altman analysis.  The novel QA analysis features thorough descriptive analysis and a validated method to estimate when INR measures lead to the same clinical decision. RESULTS: 1,666 paired INRs were collected.  Standard QA analysis deemed the Hemochron device acceptable.  Notably, the correlation between the Hemochron and laboratory was 0.9.  Our novel analysis revealed the Hemochron never reported seven INR values: 2.1, 2.7, 3.1, 3.5, 3.8, 4.1, and 4.4.  Furthermore, the Hemochron systematically inflated lower INRs and deflated higher values.  Consequently, 30% (503 / 1,666) of clinical decisions were predicted to differ using the Hemochron.  The laboratory was nearly twice as likely to report an INR below the target range (RR: 1.9, 95% CI: 1.7 – 2.1) than the Hemochron. CONCLUSIONS: Standard QA analysis missed clinically important deficiencies in the Hemochron device.  Our novel analysis revealed the Hemochron does not report all INR values and leads to incorrect clinical decisions an unacceptably large proportion of times.  The Hemochron device has been replaced in our institution.  QA analyses should be reported in explicitly clinical terms so decision-makers understand the implications to patient care.