Marietta Tomlin asks, Can Owren-Koller buffer be used instead of normal plasma to dilute anti-Xa when the are results above linearity? And if not, can you provide information on the reasoning/mechanisms as to why not?
From LaShanta Brice, DCLS, MLS (ASCP)cmSH (ASCP)cm Scientific Engagement & Clinical Education Associate, Diagnostica Stago, Inc. Because our assay uses antithrombin in the patient sample, it is not recommended to use OK Buffer as it could dilute out the antithrombin in the patient.
From Geo: Ms Tomlin, Dr. Brice’s answer applies if you are measuring unfractionated or low molecular weight heparin with your chromogenic anti-Xa assay. If you are measuring rivaroxaban or apixaban I speculate the OK buffer would factitiously reduce the factor X concentration and affect your results, as you are measuring DOAC suppression of factor X activity. I’m inviting additional expert opinions from our participants.