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Heparin release is insufficient in syringes with platelets as heparin source
Clinica Chimica Acta 395 (2008) 187
Contents lists available at ScienceDirect
Clinica Chimica Acta j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / c l i n c h i m
Letter to the editor Heparin release is insufficient in syringes with platelets as heparin source
To the editor, Differences in quantification of some parameters might have their origin in “…small clots in heparinized samples, which might lead to inhomogeneous distribution…” [1]. Statements like these and own experiences forced us to quantify heparin release and remaining coagulation ability in POCT syringes. Heparin activity in three types of liquids (electrolyte solution (perfusate), fresh frozen plasma (FFP) and whole blood) was quantified in its time dependency. The ability of clot formation was measured with rotation thrombelastography in whole blood. To simulate clinical practice tests with three types of preanalytical procedures (“resting”, “rolling” and “rotating”) were done. Required minimum amounts of heparin are defined by [2] to 8 to 12 IU/ ml in liquid formulation or 40 to 60 IU/ml in dry formulation. In Fig. 1 results from a simple E-max model calculation are given. The necessary time to reach a mean concentration of 8 IU/ml is shown. Only in syringes with liquid formulation heparin reaches the recommended concentration within a few seconds (BS2 and Monovette). A non-liquid formulation leads to a prolonged time to reach 8 IU/ml heparin in whole blood (up to more than 4.5 min). To prove the clinical importance of these findings rotation thrombelastographic tests (IN-TEM) show that mean clot firmness is still higher than 50% in 20 to 70% of all syringes after 20 min when heparin is provided in pads (full information is published online [3]). These data document that care has to be taken that so called “small clots” in reality are almost normal clots and pluggings of analyzers have to be faced.
Acknowledgments This Study was funded by Sarstedt AG&Co (Nuembrecht, Germany) and the Department of Anesthesiology of the University of Regensburg. Dr. Michael Dittmar, Department of Anesthesiology, University of Regensburg, Germany. References [1] Korte WC, Engler H, Aldebert E, Riesen WF. Heparinized blood provides equivalent results to EDTA in the CEDIA and FPIA cyclosporine immunoassays, thus facilitating routine cyclosporine determination. Clin Chim Acta 2008;390:138–40. [2] Guder WG, World_Health_Organization. Use of anticoagulants in diagnostic laboratory investigations, vol. 2. WHO/DIL/LAB/99.1 Rev; 2002. [3] Gruber M, Spaeth R, Bechmann V. Heparin release kinetics in blood gas syringes; 2008. http://epub.uni-regensburg.de/3682/.
Michael Gruber* Ruth Spaeth Volker Bechmann Department of Anesthesiology, University of Regensburg, Germany E-mail address: [email protected]. ⁎Corresponding author. Department of Anesthesiology of the University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany. Tel.: +49 941 944 7870; fax: +49 941 944 7802. 23 April 2008
Fig. 1. Calculated time [min] to reach about 8 IU/ml heparin activity in BGA syringes after blood aspiration under varying pre-analytical syringe handling conditions. Two syringe types with different heparin sources (liquid = Monovette, Sarstedt or pads = PICO 50, Radiometer) are tested. 0009-8981/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.cca.2008.04.029
Contents lists available at ScienceDirect
Clinica Chimica Acta j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / c l i n c h i m
Letter to the editor Heparin release is insufficient in syringes with platelets as heparin source
To the editor, Differences in quantification of some parameters might have their origin in “…small clots in heparinized samples, which might lead to inhomogeneous distribution…” [1]. Statements like these and own experiences forced us to quantify heparin release and remaining coagulation ability in POCT syringes. Heparin activity in three types of liquids (electrolyte solution (perfusate), fresh frozen plasma (FFP) and whole blood) was quantified in its time dependency. The ability of clot formation was measured with rotation thrombelastography in whole blood. To simulate clinical practice tests with three types of preanalytical procedures (“resting”, “rolling” and “rotating”) were done. Required minimum amounts of heparin are defined by [2] to 8 to 12 IU/ ml in liquid formulation or 40 to 60 IU/ml in dry formulation. In Fig. 1 results from a simple E-max model calculation are given. The necessary time to reach a mean concentration of 8 IU/ml is shown. Only in syringes with liquid formulation heparin reaches the recommended concentration within a few seconds (BS2 and Monovette). A non-liquid formulation leads to a prolonged time to reach 8 IU/ml heparin in whole blood (up to more than 4.5 min). To prove the clinical importance of these findings rotation thrombelastographic tests (IN-TEM) show that mean clot firmness is still higher than 50% in 20 to 70% of all syringes after 20 min when heparin is provided in pads (full information is published online [3]). These data document that care has to be taken that so called “small clots” in reality are almost normal clots and pluggings of analyzers have to be faced.
Acknowledgments This Study was funded by Sarstedt AG&Co (Nuembrecht, Germany) and the Department of Anesthesiology of the University of Regensburg. Dr. Michael Dittmar, Department of Anesthesiology, University of Regensburg, Germany. References [1] Korte WC, Engler H, Aldebert E, Riesen WF. Heparinized blood provides equivalent results to EDTA in the CEDIA and FPIA cyclosporine immunoassays, thus facilitating routine cyclosporine determination. Clin Chim Acta 2008;390:138–40. [2] Guder WG, World_Health_Organization. Use of anticoagulants in diagnostic laboratory investigations, vol. 2. WHO/DIL/LAB/99.1 Rev; 2002. [3] Gruber M, Spaeth R, Bechmann V. Heparin release kinetics in blood gas syringes; 2008. http://epub.uni-regensburg.de/3682/.
Michael Gruber* Ruth Spaeth Volker Bechmann Department of Anesthesiology, University of Regensburg, Germany E-mail address: [email protected]. ⁎Corresponding author. Department of Anesthesiology of the University of Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg, Germany. Tel.: +49 941 944 7870; fax: +49 941 944 7802. 23 April 2008
Fig. 1. Calculated time [min] to reach about 8 IU/ml heparin activity in BGA syringes after blood aspiration under varying pre-analytical syringe handling conditions. Two syringe types with different heparin sources (liquid = Monovette, Sarstedt or pads = PICO 50, Radiometer) are tested. 0009-8981/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.cca.2008.04.029