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Performance of Hemochron ACT-LR and ACT+ Test Cuvettes in Monitoring Low to Moderate Heparin Concentrations: An In
Janne Moilanen1, Marika Pada2, Pasi Ohtonen3
1Research Group of Surgery, Anesthesiology and Intensive Care Medicine, Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
Journal of Cardiothoracic and Vascular Anesthesia
|December 20, 2024
Summary
The ACT+ cartridge demonstrated superior reliability compared to the ACT-LR cuvette at moderate to high heparin concentrations. This study questions the need for a specific low-range test, highlighting significant measurement bias between the two methods.
Area of Science:
- Clinical Chemistry
- Medical Device Performance Evaluation
Background:
- The Hemochron ACT-LR cuvette is designed for heparin concentrations of 0-2.5 IU/mL, while the ACT+ cartridge is optimized for 1-6 IU/mL.
- This study investigated the comparative reliability of these two activated clotting time (ACT) measurement systems.
Purpose of the Study:
- To test the hypothesis that the ACT-LR cuvette is more reliable than the ACT+ cartridge at low to moderate heparin concentrations.
- To evaluate the performance and reliability of two different Hemochron ACT measurement systems across a range of heparin concentrations.
Main Methods:
- An in vitro study using donor blood samples spiked with unfractionated heparin to concentrations ranging from 0 to 2.5 IU/mL.
- Three measurements per concentration were performed using each test cassette (ACT-LR and ACT+) on three Hemochron Signature Elite devices, totaling 720 ACT tests.
- Data analysis employed the Bland-Altman method and intraclass correlation coefficients to assess agreement and reliability.
Main Results:
- All 360 ACT+ tests produced results, whereas 11% of ACT-LR tests exceeded the upper measurement range, primarily at heparin concentrations ≥2.0 IU/mL.
- The ACT+ cartridge showed better or equal reliability compared to the ACT-LR cuvette, based on intraclass correlation coefficients.
- A significant bias of 52 celite seconds (95% CI, 48-56) was observed between ACT-LR and ACT+ measurements, with wide limits of agreement.
Conclusions:
- The ACT+ cartridge performs comparably to the ACT-LR cuvette only up to a heparin concentration of 0.5 IU/mL.
- Above 0.5 IU/mL, the ACT+ cartridge demonstrates superior performance, challenging the clinical utility of a dedicated low-range ACT-LR test.
- Significant measurement bias exists between ACT-LR and ACT+ systems, necessitating careful consideration when transitioning between the two devices.
