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Updated: Aug 11, 2026
05:58
Evaluation of a Point-of-Care Testing Analyzer for Measuring Peripheral Blood Leukocytes
Published on: March 22, 2022
Comparison of ACT point-of-care measurements: repeatability and agreement
Y P J Bosch1, Y M Ganushchak, D S de Jong
1Department of Extra-Corporeal Circulation, University Hospital Maastricht, Maastricht, The Netherlands. ypb@scpc.azm.nl
Perfusion
|February 21, 2006
Summary
Activated clotting time (ACT) measurements during cardiopulmonary bypass (CPB) vary by analyzer. The GEM PCL showed significant differences compared to Hemochron 801 and ACT II, necessitating careful interpretation of ACT values.
Area of Science:
- Cardiovascular Surgery
- Anesthesiology
- Clinical Pathology
Background:
- Accurate heparin anticoagulation monitoring is critical during cardiopulmonary bypass (CPB).
- Activated clotting time (ACT) is the standard method for determining anticoagulation levels.
- An ACT threshold of 480 seconds is often considered a safe minimum for CPB procedures.
Purpose of the Study:
- To assess the repeatability of ACT values for three different analyzers.
- To determine significant differences in ACT measurements between the GEM PCL, Hemochron 801, and ACT II analyzers.
- To evaluate the impact of analyzer choice on ACT results during CPB.
Main Methods:
- Blood samples were collected from patients undergoing cardiovascular surgery before and after heparinization, during CPB, and post-protamine administration.
- All samples were analyzed in duplicate using the GEM PCL, Hemochron 801, and ACT II analyzers.
- Statistical analysis included Bland-Altman methods and Pearson correlation to compare ACT values and identify differences.
Main Results:
- All three ACT analyzers demonstrated acceptable repeatability.
- The GEM PCL showed statistically significant differences compared to both the Hemochron 801 (p=0.001) and ACT II (p<0.001) analyzers.
- No significant differences were found between the Hemochron 801 and ACT II analyzers (p=0.132).
- Strong correlations between differences and means were observed for GEM PCL versus the other two analyzers (r=0.68-0.76).
Conclusions:
- While all tested ACT analyzers are repeatable, the choice of analyzer significantly impacts measurement results.
- ACT values obtained from different analyzers may not be directly interchangeable.
- Clinical decisions based on ACT monitoring during CPB require awareness of potential analyzer-dependent variations.
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