Here is a fibrinogen assay question from Cara Calvo:
Hi George, I was the program director of the CLS program at Ohio Northern University in Ada, OH until this past November when I accepted a faculty position here at University of Washington.
Anyway, as I was reviewing some documents used in the UW coagulation course I will teach in the fall, I noted that one of the procedures was entitled Kinetic Fibrinogen Assay: Clauss Method. As I read the procedure it appeared to be the classic modified thrombin clotting time (TCT).
I find this confusing because I thought the kinetic fibrinogen assay and the Clauss procedure were two different methodologies. Can you clear this conundrum up for me – are these two different methodologies or not? Thanks!
Cara Calvo, MS, MT(ASCP), SH(ASCP)
Lecturer, Medical Technology Program
UW Department of Laboratory Medicine Read more »
My friend and colleague Bernadette (Bunny) Rodak of Indiana University, and chief editor of the Rodak hematology text, sent this question.
Do alcohol or cranberry products tend to increase or decrease your protime? If either raises the INR, why can’t alcohol or cranberries be used to control protimes instead of taking warfarin? Read more »
More from Kim Kinney on her patient with acquired von Willebrand syndrome:
I have some follow-up to the case I sent your way today. This patient was diagnosed with GI angiodysplasia, which has been listed in some references as a disorder associated with acquired von Willebrand disease. Our pathologist has a reference that quotes an ELISA test for antibodies directed agains VWF in the patient. Are you aware of any labs performing such an assay? Read more »
Here is a new message from Kim Kinney at Clarian in Indianapolis. I think you’ll agree, she always has interesting cases.
Hi George, We have a very interesting von Willebrand disease case. An 83 yo gentleman was admitted to our local VA for repair of a stomach lesion and had bleeding complications post-surgury. He also has had issues with GI bleeding in the past. We did an inital mix and the PTT of 45.2 seconds corrected immediately and did not show prolongation with time/temp. His PFA was very prolonged with both the ADP and EPI cartridges but he did have a low crit. We performed a factor VIII assay which was 12%, ristocetin cofactor was < 13% and his vWF antigen was 18%! Multimers are being sent for analysis. We were thinking a possible acquired von Willebrand due to his age. The hematologist is interviewing the patient again and is wondering if this could not be congenital due to his bleeding history. Is there a genetic way to distinguish congenital from acquired von Willebrand disease? Or is it usually based on family history and lab data? I will most certainly look in to the von Willebrand modules! Read more »
I received this question from Vicki Cardone, hematology supervisor at our own Children’s Hospital of Alabama, Birmingham, AL.
“Is the anti-Xa used to monitor both unfractionated heparin (UFH) and low molecular weight heparin (LMWH)? Are they the same thing?”
Hi, Vicki; good to hear from you. You can use the chromogenic anti-Xa heparin assay to monitor UFH, LMWH, and the synthetic pentasaccharide Fondaparinux (Arixtra). Although many of us maintain a separate standard curve for UFH and LMWH, researcher Dave McGlasson showed that one curve can be used for both. He calls this the “hybrid” curve. You must use a separate curve for Fondaparinux, however.
Mr. McGlasson modified Stago’s heparin standard set, but Aniara has a hybrid standard curve set that requires no modification. Aniara also provides a Fondaparinux curve. Read more »
Please check out our two newest modules, von Willebrand disease 1, which describes the physiology and clinical features, and von Willebrand disease 2, laboratory testing and therapy. You can complete the modules in 30 minutes, and earn 0.5 continuing education units for each, accredited through the Colorado Association for Continuing Medical Laboratory Education. Geo
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The silica clotting time (SCT) is a PTT-like assay that uses colloidal silica as its negatively charged particulate activator. It was first described in Chantarangkul V, Tripodi A, Arbini A, Mannucci PM. SCT as a screening and confirmatory test for detection of the lupus anticoagulants.Thromb Res 1992;67:355-65. Read more »
Bleeding Disorders | GeorgeFritsma | 
May 30, 2008 10:21 am | 
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