A-385 Performance of Activated Clotting Time ACT-LR Hemochron Signature Elite in a Pediatric Cardiac Catheterization Laboratory

Background The Activated Clotting Time (ACT) test performed as a point of care (POC) is commonly used to manage anticoagulation in a Pediatric Cardiac Catheterization Laboratory to monitor heparin anticoagulation during procedures. Children’s National Cath Lab recently transitioned from ACT Hemochron Response to Hemochron Signature Elite (HSE) using ACT-LR (low heparin range – 0.0-2.5 U/mL) cartridge. Analytical and clinical performance evaluation and verification of a new POC device is required before to place it in use for patient testing. The objective of this study was to verify the analytical performance of precision and bias estimation of this device and determine the new expected ACT-LR anticoagulation range values during Cardiac Catheterization procedures. Methods The Activated Clotting Time (ACT) test was performed using Hemochron Signature Elite ACT-LR cartridge (Werfen, USA). To verify ACT-LR precision and estimation of bias performance, two levels of assayed quality control (QC) (L1: 133, L2: 256 seconds (s), Werfen, USA) were used. Each QC level was performed during the same run (8-10 replicates) and between days (20 days). Linearity response was also evaluated using heparinized whole samples from volunteers and spiked with sodium heparin (0 to 2.5 U/mL). A comparison between Hemochron Signature Elite devices were performed using QC material and spiked heparinized whole samples, including a comparison between Hemochron Response P214 and Hemochron Signature Elite with simultaneous testing using whole blood heparinized samples collected during Cath Lab procedures (n=64) to determine the new expected ACT-LR anticoagulation range values. With-run and between-run precision (SD, %CV), including relative bias using percentage of recovery approach and device comparisons based on the obtained mean, absolute and % difference was calculated using Microsoft Excel. A box plot analysis of ACT-LR medians with each device with their interquartile range (IQR) was used to compare and determine the new expected ACT-LR anticoagulation range values. Results No potential outliers were identified using Grubb’s test. The observed with-run and between-run precision for L1 and L2 were up to 10.6%, 7.3%, and up to 8.2%, 6.5%, respectively. Estimation of relative bias using recovery approach from QC material was up to 106.0% and 106.0 for QC L1 and QC L2. Pearson coefficient correlation between Hemochron Response to Hemochron Signature Elite was >0.85. The observed %bias between Hemochron Signature Elite devices using ACT-LR cartridges were up to ±3.5% and ±1.5% using QC L1 and L2 material, and up to ±3.1% using spiked heparinized whole samples. Good linear response was observed with a Pearson coefficient correlation >0.75. ACT results of Hemochron Response P214 to Hemochron Signature Elite ACT-LR have an observed mean and median of 274 and 227s, and 285 and 210s, respectively. There is an average positive bias during heparinization of around 48 seconds for the Hemochron Response compared to the Hemochron Signature Elite in the presence of heparin Conclusion Hemochron Signature Elite ACT-LR demonstrated an acceptable performance for precision and an acceptable percentage relative bias agreement. A new ACT-LR target range of 200-350 seconds was used for the new Hemochron Signature Elite.