Female ; Heart Diseases ; surgery ; Humans ; International Normalized Ratio ; instrumentation ; Male ; Middle Aged ; Point-of-Care Systems ; Postoperative Care ; instrumentation ; Prothrombin Time ; instrumentation ; Self Care ; instrumentation ; methods

BACKGROUND: Oral anticoagulation with warfarin requires routine monitoring of prothrombin time to maintain the international normalized ratio (INR) within the appropriate therapeutic range. Coagu- Chek XS (Roche Diagnositic, Germany) is a portable coagulometer that measures the INR. We evaluated the precision and accuracy of CoaguCheck XS by comparing it with CA-1500 (Sysmex, Japan). METHODS: We analyzed the CV and the correlation of all INR results measured in 68 samples obtained from patients treated with warfarin and 10 samples from control subjects with no history of anticoagulant therapy with CoaguChek XS and CA-1500. We compared the turn-around time between two instruments and evaluated the differences between the results obtained with venous and capillary blood samples and those obtained with different lots of the test strip. We also evaluated the precision of the two instruments in 5 repeated tests with samples of normal and increased INR. RESULTS: Mean INR values of 5 repeated tests with the same samples were similar. The correlation of INR values between two instruments was excellent (r2=0.97, P=0.001), and the difference in the values between the two instruments was mostly within the 95% limit of agreement, but was shown to increase in direct proportion to INR values. The turn-around time of CoaguChek XS was shorter than that of CA-1500. The differences between venous and capillary blood and between different lots of the test trip were not significant (P>0.05). CONCLUSIONS: CoaguChek XS showed a good precision and correlation with CA-1500 with a very short turn-around time. This instrument should be clinically useful in monitoring INR of patients with oral anticoagulation.
Administration, Oral ; Anticoagulants/administration & dosage/pharmacology/*therapeutic use ; Drug Monitoring ; Humans ; International Normalized Ratio/*instrumentation ; Prothrombin Time/*instrumentation/methods ; Reproducibility of Results ; Self Care/instrumentation/methods ; Warfarin/administration & dosage/*therapeutic use

BACKGROUND: Point-of-care testing (POCT) glucometers are increasingly being used for making important therapeutic decisions and managing diabetes. We examined the analytical performance of GLUCOCARD X-METER (ARKRAY Global Business Inc., Japan) against three other glucometers and a reference laboratory method. METHODS: We evaluated the analytical performance of GLUCOCARD X-METER in comparison with three other glucometers. Studies on precision, linearity, the analysis time, and effects of hematocrit and temperature were carried out and the results were compared with those of the laboratory reference method (hexokinase method by Hitachi 760, Hitachi Co., Japan). RESULTS: GLUCOCARD X-METER showed a good linearity and within-run and total-run precision. Comparison between each glucometer and the Hitachi 7600 showed a good correlation. Although differences with the reference method were within an allowable range, all glucometers showed variable bias. Application of an insufficient amount of blood could produce some changes in test results. Changes in hematocrit were found to cause overestimation or underestimation of glucose values. For some test strips, the results were affected by prolonged exposure to room temperature or 4degrees C refrigerator. CONCLUSIONS: GLUCOCARD X-METER showed a good analytical performance in linearity, precision, and comparison. The effect of hematocrit, sample volume, and storage condition for test strips were noted and glucometers had variable deviations to both directions from laboratory reference values (<20%). The GLUCOCARD X-METER provided rapid and reliable measurements of blood glucose. It could be appropriate for monitoring blood glucose values in diabetic patients.
Blood Glucose/*analysis ; Blood Glucose Self-Monitoring/*instrumentation/methods ; Diabetes Mellitus/blood ; Hematocrit ; Humans ; Point-of-Care Systems ; Reproducibility of Results ; Sensitivity and Specificity