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Articles |
Washington University School of Medicine, Departments of
1
Pathology Box 8118,
2
Cardiothoracic Surgery Box 8234, and
3
Pediatrics Box 8116, 660 South Euclid Ave., St. Louis, MO 63110.
aAuthor for correspondence. Fax 314-454-2780; e-mail LUCHTMAN{at}pcfnotes1.wustl.edu.
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 analyzers 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.
The following articles in journals at HighWire Press have cited this article:
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S. A Spinler, A. K Wittkowsky, E. A Nutescu, and M. A Smythe Anticoagulation Monitoring Part 2: Unfractionated Heparin and Low-Molecular-Weight Heparin Ann. Pharmacother., July 1, 2005; 39(7): 1275 - 1285. [Abstract] [Full Text] [PDF] |
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D. Giavarina, M. Carta, A. Fabbri, J. Manfredi, E. Gasparotto, and G. Soffiati Monitoring high-dose heparin levels by ACT and HMT during extracorporeal circulation: diagnostic accuracy of three compact monitors Perfusion, January 1, 2002; 17(1): 23 - 26. [Abstract] [PDF] |
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M. Laposata Point-of-Care Coagulation Testing: Stepping Gently Forward Clin. Chem., May 1, 2001; 47(5): 801 - 802. [Full Text] [PDF] |
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