PB1041 - Evaluation of external quality assessment material on the renovated point of care device, United Kingdom National External Quality Assessment Scheme for Blood Coagulation studies.

Background: GEM Hemochron 100 is a point of care (POC) device for monitoring unfractionated heparin (UFH) therapy via activated clotting time testing (ACT) with cartridge – based technology to measure ACT at two levels high (ACT+) and low (ACT LR) heparin doses.

Aims: United Kingdom National External Quality Assessment Scheme for Blood Coagulation (UK NEQAS BC) conducted pilot studies where whole blood EQA ACT material containing a range of doses of UFH was evaluated on the GEM Hemochron 100 with a view to establishing a POC EQA programme.

Methods: Whole blood samples containing low and high doses of UFH which had been previously used in established UK NEQAS BC EQA programmes for ACT (ACT+ EQA, ACTLR EQA) on Hemochron Signature Elite devices, were distributed in two consecutive pilots to the users of GEM Hemochron 100 to test on ACT+ or ACT LR cartridges. Precision was evaluated via calculated coefficient of variation (CV %) in each pilot. Calculated medians in each pilot were compared to the ACT EQA programme’s medians.

Results: On the GEM Hemochron 100, a precision with CV% ranges 8 – 17 and CV% 3.5 – 4.2 was observed with low and high UFH respectively for the samples tested on ACT + cartridges. Precision with CV% ranges 21 – 31 and CV% 12 – 25 demonstrated higher variation results with low and high UFH respectively for the samples tested on ACTLR cartridges (table 1). GEM Hemochron 100 ACT+ medians compared well with the ACT+ medians for samples sent in the ACT+ EQA programme (10.8% and 3.2% difference), but for ACT LR, larger differences were observed (35.8% and 27%) (table 2).

Conclusion(s): These studies demonstrated an overall suitability of whole blood samples for testing on GEM Hemochron 100, although further work needs to be conducted with the samples for testing on ACT LR cartridges.