A pre-publication article, Young G, Perry D, The International Prophylaxis Study Group (IPSG). Laboratory assay measurement of modified clotting factor concentrates: a review of the literature and recommendations for practice. J Thromb Haemostas pre-publication, 1-22-19 provides advice on how to measure extended half-life and B-domain-deleted factor concentrates VIII and IX. The article illustrates the wide variations in PTT-based one-stage clot-based assay results for the various new preparations related to the various reagent activators silica, kaolin, ellagic acid, or polyphenols. The writers show that the currently available chromogenic substrate factor VIII assays recover reasonably accurate results for all preparations. Chromogenic factor IX assays are approved for use in only a handful of locations but provide accurate measurement of factor IX concentrate therapy.
Posts - Bleeding Disorders
Jan 30, 2019 7:53am
Jan 29, 2019 4:58pm
Beginning with a 2016 Quick Question and continuing to our most recent post in March, 2018, we've devoted altogether six entries to the 2012 CDC refinements of the Nijmegen-Bethesda assay. These have culminated in the following material, which appears in Fritsma GA, Chapter 41, Laboratory Evaluation of Hemostasis; in Keohane EM, Otto C, Walenga JM. Rodak's Hematology: Clinical Principles and Applications, Sixth Edition, Elsevier, 2019. This latest edition makes its debut at the 2019 American Society for Clinical Laboratory Science Clinical Laboratory Educators' Conference, February 21–23 in Baltimore, commorating the life of its original editor, Bernadette Rodak, who passed away in March, 2016.
Jan 29, 2019 2:21pm
A patient experiences chronic moderate bleeding from a surgical site and venipuncture sites over 48 months. The bleeds consistently require intervention. There is no epistaxis and minor bruising. The only diagnostic laboratory result is impaired aggregation epinephrine and ADP agonists, and absence of arachidonic acid-induced aggregation. All other hemostasis and hematology results report within their respective reference intervals. The results appear to indicate a platelet signal transduction (signalling) disorder, or "aspirin-like disorder (ALD)." Platelet signaling disorders are often described, but seldom defined.