Agreement between Coaguchek XS and STA-R Evolution (Hepato Quick) INR results depends on the level of INR

• Published in: Thrombosis research Vol. 136; no. 3; pp. 652 - 657
• Main Authors: Biedermann, Joseph S, Leebeek, Frank W.G, Buhre, Peter N, de Lathouder, Sacha, Barends, Jan P.F, de Maat, Moniek P.M, van der Meer, Felix J.M, Kruip, Marieke J.H.A
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01-09-2015
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Anticoagulants; Anticoagulants - administration & dosage; Blood Coagulation Tests; Coumarin; Drug Monitoring - methods; Female; Hematology, Oncology and Palliative Medicine; Humans; International Normalized Ratio; International Normalized Ratio - methods; Male; Middle Aged; Point-of-Care Systems; Point-of-Care Testing; Reagent Strips; Reproducibility of Results; Sensitivity and Specificity; Thromboembolism - blood; Thromboembolism - diagnosis; Thromboembolism - drug therapy; Treatment Outcome; Young Adult; International Normalized Ratio; Blood Coagulation Tests; Anticoagulants; Point-of-Care Systems; Coumarin
• ISSN: 0049-3848; 1879-2472
• DOI: 10.1016/j.thromres.2015.06.037

Abstract Introduction Introducing point-of-care (POC) INR measurement to monitor anticoagulant therapy may be beneficial for both patients and anticoagulation clinics. However, agreement between POC and laboratory INR results is still unclear, especially at sub- and supratherapeutic levels. Therefore we investigated the analytical and clinical agreement between POC INR results of the Coaguchek XS and laboratory INR results of the STA-R Evolution. Materials and Methods Paired POC and laboratory INR results were obtained and analyzed in 3257 patients aged 18–104 years between August 2008 and March 2014. Results Mean difference between POC and laboratory results ranged from − 0.18 (95%CI − 0.20;-0.16) INR point for POC results 2.0-3.0, up to 1.14 (95%CI 0.87;1.42) INR point for POC results 7.1-8.0. In the therapeutic range (POC INR 2.0-4.0), mean difference between POC and laboratory results was − 0.13 (95%CI − 0.15;-0.12) INR point. At subtherapeutic (POC INR < 2.0) and supratherapeutic (POC INR > 4.0) INR levels, mean differences were − 0.13 (95%CI − 0.15;-0.11) and 0.72 (95%CI 0.63;0.80) INR point, respectively. Clinical agreement regarding therapeutic range was present in 92.0% (POC within range), 67.7% (POC below range) and 87.6% (POC above range) of the paired measurements. We observed ≥ 15% INR difference between the POC and laboratory result in 14.8% (POC INR 2.0-4.0), 17.0% (POC INR < 2.0) and 47.8% (POC INR > 4.0) of the paired measurements. Conclusions POC and laboratory INR results were strongly correlated within the therapeutic range and differences between results become larger with increasing INR. Clinical disagreement between laboratory and POC results occurs often at both sub- and supratherapeutic INR levels.