Effects of pre-analytical variables on the anti-activated factor X chromogenic assay when monitoring unfractionated heparin and low molecular weight heparin anticoagulation.

Author(s): McGlasson DL, Kaczor DA, Krasuski RA, Campbell CL, Kostur MR, Adinaro JT

Publication: Blood Coagul Fibrinolysis, 2005, Vol. 16, Page 173-6

PubMed ID: 15795534 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine if the use of different anticoagulants or the ratio of blood to anticoagulant during specimen collection affects anti-FXa assay results or aPTT for patients receiving UFH and LMWH therapy. Plasma specimens were stored at -70 degrees C prior to analysis.

   Summary of Findings:

   Specimens from UFH patients collected into 3.8% sodium citrate with ratio of 6:1 (blood: anticoagulant) showed a statistically significant increase in aPTT (p=0.06) with an average time of 127.2 s versus 105.4 s when specimens were collected using standard methods (3.2% sodium citrate and a 9:1 blood to anticoagulant ratio). However, some UFH specimens had aPTT times over 300 s which could have skewed the mean. No other combinations of anticoagulant and blood/anticoagulant ratio resulted in statistically significant differences in aPTT for patients receiving UFH or LMWH therapy. There were several aPTT times which did not correlate with the amount of heparin, indicating an effect of other variables besides heparin on aPTT. Importantly, neither blood to anticoagulant ratio nor type of anticoagulant affected anti-FXa assay results for either heparin therapy suggesting this assay is better suited for monitoring heparin patients.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen

   Diagnoses:

   • Coronary Artery Disease
   • Other diagnoses

   Platform:

   Analyte	Technology Platform
   Protein	Hematology/ auto analyzer

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Diagnosis/ patient condition	Deep vein thrombosis Antiphospholipid antibody syndrome Recurrent spontaneous abortion Other diagnoses
   Preaquisition	Other drugs	Low molecular weight heparin Unfractionated heparin
   Biospecimen Acquisition	Anticoagulant	Sodium citrate Citrate-theophylline-adenosine-dipyridamole
   Biospecimen Aliquots and Components	Aliquot size/volume	9:1 blood to anticoagulant ratio 6:1 blood to anticoagulant ratio

   View more