Factor VIII and XIII Deficiency?

I had a recent communication through the American Society for Clinical Laboratory Science Consumer Forum in which a patient with severe chronic bleeding symptoms had been diagnosed as having both a factor VIII and a factor XIII deficiency. Given prevalence data, I compute the odds of this combination as 1 in 10 billion, and have found no […]

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Dec 20 2010

george

Should We Test for LA?

From “MaryMay:” Should this patient be tested for lupus anticoagulant (LA)? There is no history of coagulation factor disorders or liver disease. The activated partial thromboplastin time (PTT) results pre-hip replacement surgery were 41.4 sec (reference interval 25-32 sec) with prothrombin time (PT) at 9.6 sec (9.8-11.4), INR 0.9. Six weeks later, after postponement of […]

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More on Dabigatran and Rivaroxaban

Here is a link to a Heartwire summary of 2010 clinical trial reports on dabigatran (Pradaxa, Boehringer-Ingelheim) and rivaroxaban (Xarelto, Bayer and Johnson & Johnson), with some descriptions of progress in development of additional oral antithrombotics.

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Prolonged PT and PTT That Don’t Correct

George, I am trying to work on a hemostasis project for school and I do not have any experience at all in a hemostasis laboratory apart from running PT and PTTs. What if a patient has an abnormal PT and PTT that are not corrected by mixing study? My guess is because it didn’t correct, […]

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Quick Question Summary: Specimen Freezing

Our specimen freezing question arose in response to an October 6 post from Anne-Marie Quinn, Janssen-Ortho, Canada. The responses had a degree of unanimity not often seen on Fritsma Factor! Here they are: How do you freeze coagulation assay plasma samples? 1. Place in a -20°C (household) freezer: 10 (20%) 2. Place in a -70ºC (laboratory) freezer: […]

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PFP Versus PPP

From Robert Gosselin at UC-Davis in Sacramento: Hello GF, Just as a side note, in the lupus anticoagulant comment you indicated “…which is performed using PFP, plasma whose platelet count is less than 10,000/mcL.” One has to assume that the abbreviation PFP is for platelet-free plasma as opposed to platelet-poor plasma. The former, platelet free […]

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False Positive Phospholipid Neutralization

G Pihan from Beth Israel Deaconess asks, “What is the incidence of false positive hexagonal phospholipid neutralization tests in the presence of a strong (400-800 BU) factor VIII inhibitor?” Great question! Hexagonal-phase phosphatidyl ethanolamine is the chemical formulation for the phospholipid neutralization reagent used in Diagnostica Stago’s Staclot-LA lupus anticoagulant (LA) confirmatory assay. Their hex-phase phospholipid is widely regarded as […]

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Pre-op Plavix Test

From Dan Hood: What testing do you recommend for Plavix effect for patients preoperatively? We have neurosurgeons testing the morning of surgery and are looking for some options. Hi, Dan, thank you for your question. Plavix is a thienopyridine that suppresses platelet activation by blocking membrane ADP receptors. The reference method is platelet aggregometry using […]

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Short APTT Sensitivity Survey for Physicians

Fritsma Factor recently posted a brief survey asking laboratory scientists to characterize the sensitivity of their “routine” activated partial thromboplastin time (APTT) assay for lupus anticoagulant (LAC). This is a three-question follow-up survey for physicians. To go direct to the survey, select APTT Sensitivity Survey. For further explanation, please continue reading. The activated partial thromboplastin time (APTT) assay […]

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Apixiban Phase 3 Trial Halted

On 11/19/10, Pfizer and Bristol Myers Squibb discontinued the APPRAISE-2 phase 3 trial of Apixiban in high risk patients with acute coronary syndrome. Apixiban bleeding risks were not offset by its antithrombotic benefit in the high-risk patient population. Details are available from theheart.org. At least two trials appear to show that Apixiban, which is a direct […]

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Factor VIII and XIII Deficiency?

Should We Test for LA?

More on Dabigatran and Rivaroxaban

Prolonged PT and PTT That Don’t Correct

Quick Question Summary: Specimen Freezing

PFP Versus PPP

False Positive Phospholipid Neutralization

Pre-op Plavix Test

Short APTT Sensitivity Survey for Physicians

Apixiban Phase 3 Trial Halted

George Fritsma MS MLS

Cheat Sheets from George

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