PB0556 - Evaluation of the ACL TOP 970 CL analyser for clotting, chromogenic and immunoturbidimetric assays for thrombophilia

Background: The ACL TOP 970 CL (IL) is a new, fully automated random-access analyser. The analytical module is divided into the main system (clotting, chromogenic and immunoturbidimetric testing) and the CL system (chemiluminescence testing), allowing all methods to be performed simultaneously.

Aims: Evaluate the performance of the ACL TOP 970 CL main system against the ACL TOP 700 (IL) for measurement of the main thrombotic parameters.

Methods: The following HemosIL (Werfen) methods were evaluated according to manufacturer settings. Chromogenic assays: Liquid Antithrombin (AT), Protein C (PC), Plasminogen (Plg). Immunoturbidimetric assays; Free Protein S (FPS) and Homocysteine (HCY). Clotting assay; Factor V Leiden Screen (FVL-S). Precision was assessed using frozen pooled normal plasma. Samples were tested on the ACL TOP 970 CL and the ACL TOP 700 for method comparison. Samples were all single/double spun (2000g for 10 minutes) residual plasma aliquots stored at -70 degrees.

Results: Assays displayed excellent repeatability (n=10) with CV < 2.7% for AT, PC, Plg, FPS and < 2.9% for HCY and FVL. Reproducibility (n=8) was < 5.5% for AT and PC. Calibration curves (n=12) across the calibrated assays (AT, PC, HCY, Plg) all generated R2 >0.991. Assays showed strong agreement between the ACL TOP 970 CL vs ACL TOP 700. AT (n=96), mean IU/mL: 0.95 vs 0.98, R2 = 0.964. PC (n=101), mean IU/mL: 0.90 vs 0.97, R2 = 0.981. Plg (n=27): mean 75% vs 77%, R2 = 0.991. FPS (n=48), mean IU/mL: 0.80 vs 0.80, R2 = 0.997. Hcy (n=106), umol/L: 26.1 vs 25.6, R2 0.992. FVL screen (n=106): 72 wildtype, 34 heterozygous, complete agreement across analysers, R2 = 0.965.

Conclusion(s): The ACL TOP 970 CL is a precise and reliable analyser in the determination of chromogenic, clotting and immunoturbidimetric assays. The assays showed good comparison in performance between the ACL TOP 970 CL and the ACL TOP 700.