PO0026 - Activated Clotting Time : Setting Target Values of CPB when Changing from Hemochron Resopnse to i-STAT

Background: Activated clotting time (ACT) is a point-of-care coagulation test monitored an unfractionated heparin (UFH) in whole blood of patients receiving heparin therapy. The target value of the ACT should be changed according to the devices type.

Aims: The purpose of this study was to set up the target value ACT of i-STAT on cardiopulmonary bypass(CPB) patient .

Methods: We perfomed precision tests , which used quality control materials to reproducibility, and comparison tests with 42 samples. We performed target setup tests with CPB patient samples (310 samples/74 patients) to reflect clinically meaningful UFH concentrations. Hemochron Response (Instrumentation Laboratory, USA; HR) was tested in a non-preheat method (FTCA510 tube). i-STATs (Abbott, USA; i-STAT1, i-STAT2) was tested in a preheat method (ACT Celite® cartridge).

Results: Precision test did not exceed the manufacturer's acceptable range (HR-level 1 :1.81, level 2 :0.75, i-STAT1-Level 1: 2.70, Level 2: 2.08, i-STAT2-Level 1: 2.18, Level 2: 3.08). The difference between the hemocron response and the i-STAT devices in the comparative test was as follows (R i-STAT1: 0.9053, i-STAT2: 0.9074, mean difference i-STAT1: -10.2%, i-STAT2: -12.0%). i-STAT1 and 2 showed a good correlation and the mean difference showed similar results (R²: 0.9769, mean difference: -2.0%). The R value of the target setup tests was 0.8543.

Conclusion(s): HR is known to have a linearity of 80 to 600 seconds and, i-STAT is known 50 to 1,000 seconds. Their results were different due to differences in slope, but the same UFH concentration was reflected because the same specimen was performed at the same time. The setting of the target value used medical decision point (MDP) analysis because the R was 0.8543. Based on 480 seconds, the minimum was 363.6 seconds, the maximum was 393.8 seconds, and the mean was 378.7 seconds. We decided that the target vlaue of i-STAT is 380 seconds.