From Nancy Fabbrini: We have a patient on an argatroban bridge to warfarin. He is a very difficult draw so the service has been drawing blood from the central access device. They have been withdrawing 20 mL of blood before drawing the tube for coagulation testing. Is that sufficient, i.e. do the same “rules” for a line with heparin apply to argatroban? Thank you.
Category: Specimen Management
From our summer, 2014 Quick Question, What is your policy for managing overfilled coagulation specimen tubes?
a. We reject overfilled tubes; results are likely to be invalid. 116 votes, 69%
b. We accept overfilled tubes; overfilling doesn’t affect results. 28 votes, 17%
c. We never see overfilled tubes. 24 votes, 14%
This was posted by a colleague on another forum. We have noticed that newborn babies plasma, after three weeks on extracorporeal membrane oxygenation (ECMO) becomes dark brown. On our instrument, the fibrinogen rises to approximately 800 mg/dL, though a reference lab reports it as critically low. We also notice falsely elevated platelet counts, for instance, 150,000 by impedance and 50,000 by optical, but the manual estimate is 15,000. The manufacturer says the fibrinogen could cause a falsely elevated platelet count. Could there be a common denominator causing these interferences?
George presented the first part of a three-part AACC webinar series, Quality Assurance in Hemostasis; What Makes Us Different? A question arose about Ebola virus specimen management. Though not specifically related to hemostasis, it seems appropriate to provide a link to the US Centers for Disease Control and Prevention (CDC) specimen precautions. What the CDC document does not address is potential instrument contamination. George suggested specimens identified as Ebola should be tested on isolated instruments. How do you manage infections specimens, and what do you recommend?
George is working with Dr. Jeanine Walenga, coagulation editor, on the “Methods” chapter for the fifth edition of Hematology, Clinical Principles and Applications. (The Rodak Hematology textbook published by Elsevier). While most hemostasis specimens are collected in evacuated tube systems, we use syringes for difficult draws or special applications. When transferring syringe blood to an evacuated tube, the general rule, outlined in CLSI H3-A6, is to detach the needle, affix a safety transfer device, pierce the tube closure, and allow the negative pressure of the tube to draw the proper volume of blood from the syringe, ensuring it runs gently down the side of the tube. Read more »
From Joanna Carroll: I was recently told that samples should be double spun prior to long term freezing. Except in the case of heparin testing, I cannot find any evidence to support this. Also can you tell me if there are recommendations on how to handle samples for fibrinogen, D-dimer and unfractionated heparin anti-Xa assays? Our fibrinogen package insert only mentions how long the sample is good for at room temperature, and our D-dimer insert only mentions how to handle the sample after freezing. The CLSI document does not cover these tests. Thanks for your help.
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From Kim Kinney at Indiana University Health:
Hi George. We frequently get asked how long to stop an unfractionated heparin infusion before drawing for a partial thromboplastin time (PTT) from a central line or peripheral stick above the infusion site. We have always referred them to pharmacy. is there a standard practice used by nursing at other institutions that someone would share?