Point-of-care testing of activated clotting time in the ICU: is it relevant?

2016 ◽  
Vol 25 (11) ◽  
pp. 608-612 ◽  
Author(s):  
Ellenora Brown ◽  
Jody Clarke ◽  
Karen-leigh Edward ◽  
Jo-Ann Giandinoto
Keyword(s):  
Point Of Care ◽  
Point Of Care Testing ◽  
Clotting Time ◽  
Activated Clotting Time

scholarly journals Evaluation of the TAS Analyzer and the Low-Range Heparin Management Test in Patients Undergoing Extracorporeal Membrane Oxygenation

2001 ◽  
Vol 47 (5) ◽  
pp. 858-866 ◽  
Author(s):  
Theresa M Ambrose ◽  
Curtis A Parvin ◽  
Eric Mendeloff ◽  
Lori Luchtman-Jones
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Management Strategy ◽  
Point Of Care ◽  
Point Of Care Testing ◽  
Clotting Time ◽  
Blood Draw ◽  
Membrane Oxygenation ◽  
Activated Clotting Time ◽  
The Relationship ◽  
Heparin Dosage

Abstract Background: The new Low-Range Heparin Management Test (LHMT), a method for point-of-care testing (POCT) of heparinization, has been designed to function at the low to moderate heparin concentrations typically found in patients undergoing extracorporeal membrane oxygenation (ECMO). In this study, the new method is compared with two POCT methods and a laboratory-based anti-Xa assay. Methods: We obtained 760 whole blood samples from 13 patients undergoing ECMO. All samples were tested immediately by the LHMT, the Activated Clotting Time (ACT) test, and its low-range counterpart (ACT-LR). Aliquots from the same blood draw were frozen for later anti-Xa analysis using the Diagnostica Stago method on the Roche Cobas Fara-II. Results: The precision was best for duplicate citrated LHMT samples (CV = 3.1%). LHMT clotting times (overall median, 162 s) were typically shorter than ACT or ACT-LR times (247 and 235 s, respectively). The relationship between the LHMT and the other POCT methods differed significantly from patient to patient (P <0.0001), and a meaningful single relationship between the methods could not be obtained. The overall correlation coefficient between clotting time values and actual heparin concentrations was ≤0.48 for each of the instruments tested, although time plots of each analyzer’s data suggested that they detected heparin dosage changes within single patients. Conclusions: The performance of the LHMT on the TAS Analyzer is equivalent to that of currently commercially available POCT methods. The lack of agreement between absolute clotting time values and heparin concentrations suggests the need for reexamination of current ECMO patient management strategy.

scholarly journals Point-of-Care Measurement of Activated Clotting Time for Cardiac Surgery as measured by the Hemochron Signature Eliteand the Abbott i-STAT: Agreement, Concordance, and Clinical Reliability

2019 ◽  
Author(s):  
Daniel Dirkmann ◽  
Elisabeth Nagy ◽  
Martin Walter Britten ◽  
Juergen Peters
Keyword(s):  
Cardiac Surgery ◽  
Linear Correlation ◽  
Point Of Care ◽  
Clotting Time ◽  
Cohen’S Kappa ◽  
Cohen's Kappa ◽  
Activated Clotting Time ◽  
Target Values ◽  
Heparin Anticoagulation ◽  
Parallel Measurements

Abstract Background: Since inadequate heparin anticoagulation and insufficient reversal can result in complications during cardiopulmonary bypass (CPB) surgery, heparin anticoagulation monitoring by point-of-care (POC) activated clotting time (ACT) measurements is essential for CPB initiation, maintainance, and anticoagulant reversal. However, concerns exist regarding reproducibility of ACT assays and comparability of devices. Methods: We evaluated the agreement of ACT assays using four parallel measurements performed on two commonly used devices each (i.e., two Hemochron Signature Elite (Hemochron) and two Abbott i-STAT (i-STAT) devices, respectively). Blood samples from 30 patients undergoing cardiac surgery on CPB were assayed at specified steps (baseline, after heparin administration, after protamine administration) with four parallel measurements (two of each device type) using commercial Kaolin activated assays provided by the respective manufactures. Measurements were compared between identical and different device types using linear regression, Bland-Altman analyses, and calculation of Cohen’s kappa coefficient. Results: Parallel i-STAT ACTs demonstrated a good linear correlation (r=0.985). Bias, as determined by Bland-Altman analysis, was low (-3.8s; 95% limits of agreement (LOA): -77.8 -70.2s), and Cohen’s Kappa demonstrated good agreement (kappa=0.809). Hemochron derived ACTs demonstrated worse linear correlation (r=0.782), larger bias with considerably broader LOA (-13.14s; 95%LOA:-316.3-290s), and lesser concordance between parallel assays (kappa=0.554). Although demonstrating a fair linear correlation (r=0.815), parallel measurements on different ACT-devices showed large bias (-20s; 95% LOA: -290-250s) and little concordance (kappa=0.368). Overall, disconcordant results according to clinically predefined target values were more frequent with the Hemochron than i-STAT. Furthermore, while discrepancies in ACT between two parallel iSTAT assays showed little or no clinical relevance, deviations from parallel Hemochron assays and iSTAT versus Hemochron measurements revealed marked and sometimes clinically critical deviations. Conclusion: Currently used ACT point-of-care devices cannot be used interchangeably. Furthermore, our data question the reliability of the Hemochron in assessing adequacy of heparin anticoagulation monitoring for CPB.

A Multicenter Comparison of 2 Point-of-Care Activated Clotting Time Test Systems

2019 ◽  
Vol 4 (3) ◽  
pp. 468-470
Author(s):  
Evelien W.M. Kemna ◽  
Mark W.M. Schellings ◽  
Georgios J. Vlachojannis ◽  
Florian Falter ◽  
Antoinette Milané-Santman ◽  
...  
Keyword(s):  
Point Of Care ◽  
Clotting Time ◽  
Test Systems ◽  
Activated Clotting Time ◽  
Time Test

A comparative analysis of four activated clotting time measurement devices in cardiac surgery with cardiopulmonary bypass

Perfusion ◽  
2020 ◽  
pp. 026765912094935
Author(s):  
Han Li ◽  
Cyril Serrick ◽  
Vivek Rao ◽  
Paul M Yip
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
System Analysis ◽  
Point Of Care ◽  
Measurement Range ◽  
Medical Decision ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Decision Points ◽  
Heparin Anticoagulation

Background: In cardiac surgery on cardiopulmonary bypass (CPB), heparin anticoagulation is monitored by point-of-care measurement of activated clotting time (ACT). The objective of this study was to compare four ACT systems in cardiac surgery in terms of their reproducibility, agreement and potential clinical impact at relevant medical decision points. Methods: The study included 40 cardiac surgery patients. Samples were taken at five time points before (T1), after heparinization for CPB (T2, T3, T4), and after heparin reversal (T5). The reproducibility, correlation, and differences in ACT values were assessed with two devices from each of the four ACT systems: Instrumentation Laboratory Hemochron Elite (Hmch), Medtronic HMS Plus (HMS), Abbott i-STAT, and Helena Abrazo. Subrange analyses were performed for low ACT values (results from T1, T5) and high ACT values (results from T2, T3, T4). Results: Within-system analysis showed strong linear correlation between paired measurements (R = 0.968-0.993). However, Hmch showed poorer reproducibility with highest proportion of values that exceed a difference of 10% and highest overall standard error of 74 seconds across the measurement range compared to that of the others (range 39-47 seconds, respectively). For inter-system comparison, using Hmch as reference, ACTs were strongly correlated as follows: HMS (R = 0.938), i-STAT (R = 0.911), and Abrazo (R = 0.911). Agreement analysis in the high ACT range showed HMS tended to have higher ACT values with +11% bias over Hmch, whereas i-STAT (–8% bias) and Abrazo (–13% bias) tended to underestimate. Post-protamine ACT results were dependent on device type where Hmch yielded highest post-protamine ACT (+13% higher than baseline) compared to –16% for HMS, –10% for iSTAT and 0% for Abrazo. Conclusions: Each device had individual reproducibility and biases, which may impact peri-operative heparin management. Careful validation must be undertaken when adopting a different method as decision limits would be affected. Clinicians should also be cautious using ACT as the only indicator for full heparin reversal.

A two site comparison of two point-of-care activated clotting time systems

2017 ◽  
Vol 55 (1) ◽  
pp. e13-e16 ◽  
Author(s):  
Evelien W.M. Kemna ◽  
Charline Kuipers ◽  
Agnes M.A. Oude Luttikhuis-Spanjer ◽  
Stefan Majoor ◽  
Renate Boudrie ◽  
...  
Keyword(s):  
Point Of Care ◽  
Clotting Time ◽  
Activated Clotting Time ◽  
Time Systems

scholarly journals Point-of-Care Measurement of Activated Clotting Time for Cardiac Surgery as measured by the Hemochron Signature Eliteand the Abbott i-STAT: Agreement, Concordance, and Clinical Reliability

2019 ◽  
Author(s):  
Daniel Dirkmann ◽  
Elisabeth Nagy ◽  
Martin Walter Britten ◽  
Juergen Peters
Keyword(s):  
Cardiac Surgery ◽  
Linear Correlation ◽  
Point Of Care ◽  
Clotting Time ◽  
Cohen’S Kappa ◽  
Cohen's Kappa ◽  
Activated Clotting Time ◽  
Target Values ◽  
Heparin Anticoagulation ◽  
Parallel Measurements

Abstract Background: Since inadequate heparin anticoagulation and insufficient reversal can result in complications during cardiopulmonary bypass (CPB) surgery, heparin anticoagulation monitoring by point-of-care (POC) activated clotting time (ACT) measurements is essential for CPB initiation, maintainance, and anticoagulant reversal. However, concerns exist regarding reproducibility of ACT assays and comparability of devices. Methods: We evaluated the agreement of ACT assays using four parallel measurements performed on two commonly used devices each (i.e., two Hemochron Signature Elite (Hemochron) and two Abbott i-STAT (i-STAT) devices, respectively). Blood samples from 30 patients undergoing cardiac surgery on CPB were assayed at specified steps (baseline, after heparin administration, after protamine administration) with four parallel measurements (two of each device type) using commercial Kaolin activated assays provided by the respective manufactures. Measurements were compared between identical and different device types using linear regression, Bland-Altman analyses, and calculation of Cohen’s kappa coefficient. Results: Parallel i-STAT ACTs demonstrated a good linear correlation (r=0.985). Bias, as determined by Bland-Altman analysis, was low (-3.8s; 95% limits of agreement (LOA): -77.8 -70.2s), and Cohen’s Kappa demonstrated good agreement (kappa=0.809). Hemochron derived ACTs demonstrated worse linear correlation (r=0.782), larger bias with considerably broader LOA (-13.14s; 95%LOA:-316.3-290s), and lesser concordance between parallel assays (kappa=0.554). Although demonstrating a fair linear correlation (r=0.815), parallel measurements on different ACT-devices showed large bias (-20s; 95% LOA: -290-250s) and little concordance (kappa=0.368). Overall, disconcordant results according to clinically predefined target values were more frequent with the Hemochron than i-STAT. Furthermore, while discrepancies in ACT between two parallel iSTAT assays showed little or no clinical relevance, deviations from parallel Hemochron assays and iSTAT versus Hemochron measurements revealed marked and sometimes clinically critical deviations. Conclusion: Currently used ACT point-of-care devices cannot be used interchangeably. Furthermore, our data question the reliability of the Hemochron in assessing adequacy of heparin anticoagulation monitoring for CPB.

Anticoagulation Monitoring

2004 ◽  
Vol 17 (5) ◽  
pp. 317-326 ◽  
Author(s):  
Maureen A. Smythe ◽  
Anne Caffee
Keyword(s):  
Therapeutic Range ◽  
Gold Standard ◽  
Point Of Care ◽  
International Normalized Ratio ◽  
Heparin Therapy ◽  
Thrombin Inhibitor ◽  
High Dose ◽  
Specific Procedure ◽  
Clotting Time ◽  
Activated Clotting Time

Optimal management of anticoagulant therapy requires an understanding of the laboratory tests often employed to guide therapy. The activated partial thromboplastin time (aPTT) can detect abnormalities in the intrinsic and common clotting pathways. Despite numerous limitations in the aPTT test, it remains the gold standard for monitoring unfractionated heparin and direct thrombin inhibitor therapy. The aPTT can be performed in the central laboratory or at the bedside (point of care [POC] testing). The activated clotting time (ACT) is a POC test that is routinely employed to monitor high-dose heparin during invasive and surgical procedures. The ACT therapeutic range will depend on the specific procedure or surgery being performed. Heparin levels are becoming more routinely available and are used to establish the aPTT therapeutic range for heparin therapy as well as for direct monitoring of heparin and low-molecular-weight heparin therapy. The international normalized ratio (INR) is the gold standard for monitoring warfarin patients. The target INR depends on the indication for anticoagulation. POC monitoring for warfarin is becoming increasingly used. Clinicians should have a thorough understanding of the benefits as well as the limitations of warfarin POC monitoring.

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