Thrombolysis in stroke patients: Comparability of point-of-care versus central laboratory international normalized ratio

Background In acute stroke patients, thrombolysis is one gold standard therapy option within the first four hours after the ischemic event. A contraindication for thrombolysis is an International Normalized Ratio (INR) value >1.7. Since time is brain , rapid and reliable INR results are fundamental. Aim was to compare INR values determined by central laboratory (CL) analyzer and Point-of-Care Testing(POCT)-device and to evaluate the quality of POCT performance in cases of potential therapeutic thrombolysis at a certified stroke unit. Methods In 153 patients INR measurements using POCT-devices (HEMOCHRON Signature Elite®) were compared to INR measurements (BCS ® XP) performed at the central laboratory. Outlier evaluation was performed regarding the critical thrombolysis cut-off. Results Overall, we demonstrated a significant correlation ( r = 0.809, p <0.0001) between both measurement methods. Mean value of the absolute difference between CL-INR and POCT-INR measurements was 0.23. In 95.4% of these cases, no differences regarding the critical cut-off (INR 1.7) were observed. POCT-INR values tended to be higher than the CL-INR values ( p = 0.01). In 4.6% cases, a different value regarding thrombolysis cut-off was found. All patients were >75 years. Conclusions POCT-INR measurements based on our POCT concept are suitable to determine INR values in critical stroke patients. Nevertheless, outlier evaluation is mandatory.