Category: Bleediing Disorders

What is PF3?

Each year George enjoys the opportunity to teach in Dr. Elaine Keohane’s graduate course, CLSC 5124, Advanced Hemostasis at Rutgers University School of Health Related Professions. Our students are experienced medical laboratory scientists from all over the world, and they bring a wealth of practical knowledge. Dr. Keohane is teaching a section on platelet physiology this week, and the question came up, what is platelet factor 3? I’m old enough to know the answer, but I’d like to hear from our participants. In addition to defining PF3, also please report what coagulation laboratory assay we used to “diagnose” PF3 deficiency.

In Vivo Hemolysis

Irene Regan writes that despite doing major literature searches there seems to be no consensus regarding what coagulation results should be released when there is a suspicion of in vivo hemolysis such as in disseminated intravascular coagulation (DIC), when the samples are grossly haemolysed. Currently, Irene issues a fibrinogen (Clauss) and in this case she generally confirms this using a correction with normal plasma due to haemolysed nature of the sample or because the fibrinogen is extremely low. Do you have any advise?

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Factor XIII Concentrate

In February 2011, the plasma-derived CLS Behring factor XIII concentrate Corifact™ received US Food and Drug Administration (FDA) clearance to provide bleeding prophylaxis for patients with rare congenital factor XIII (fibrin stabilizing factor) deficiency. In January, 2013, the FDA extended Corifact’s indication to include management of perioperative bleeding in factor XIII-deficient patients. The Corifact package insert is attached here:

Corifact Prescribing Information

Factor VIII Inhibitor?

From Deborah Whetzel, Children’s Hospital of the King’s Daughters, Norfolk, VA: We’ve had a couple patients lately that demonstrated inhibition but their factor VIII results are within normal limits or even elevated. The result values differ 30–40% typically between dilutions but as they’re diluted more, the values go up to 300 or 400%. FVIII values that high seem really odd to me. We dilute to 1:160, as I’ve seen recommended, with results to that point continuing to get higher. Have you seen this occur and is there something that we should be doing? Thanks for your help.

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Prolonged PT and PTT

A message from Vilas Hiremath:

Dear George, hello. Female 30 yrs underwent laparoscopy, started bleeding. Prothrombin time (PT) and partial thromboplastin time (APTT, PT)  prolonged, both mixing study 1:1 corrected. Normal fibrinogen and thrombin time (TT). Factor X, VIII. II normal, factor V is 6.0%. Dilute Russell viper venom time (DRVVT) screen and confirm both prolonged, unable to get ratio. My question is 1) why DRVVT is sensitive to factor V deficiency being snake venom, and 2) whether antiphospholipid antibody (APL) involved with activated protein C (resistance?) APC (R?) (resistance and “R” added by Geo.) Whether a case of thrombosis presented with bleeding. Your comments please.

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Prolonged PT, TT, and PTT

From Ning Tang: Hi, George, I come from a clinical laboratory in China. We met a confusing case today and want to get your suggestion: A patient had a prolonged prothrombin time (PT, 20s), partial thromboplastin time (APTT, PTT, 52s) and thrombin time (TT, 127s). Fibrinogen activity is within reference interval (by both Clauss method and TEG), also the patient shows slight bleeding symptoms, is this dysfibrinogenemia? How to confirm it? Thanks for your help!

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WFH Research RFP

The Word Federation of Hemophilia has just issued a research request for proposals. This is short notice, however, if you have a proposal, WFH will accept a letter of intent by August 31, 2013. Click WFH RFP for submission details.

FVIII Inhibitor Assays

From Saravanan Vinayagam: We are trying to set up the factor VIII inhibitor assay on our ACL TOP analysers. Has anyone got an SOP or previous experience in validating inhibitor assay in an automated analysers? Thank you.

Hello, Saravanan Vinayagam, and thank you for your post. I’m hoping that an IL technical representative will see this and offer some assistance. Geo.

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