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Factor XII and Sickle Cell Crisis

I had a conversation with a colleague who mentioned they were seeing decreased factor XII activity and antigen levels during sickle cell crisis. I found two references on reduced contact factors in sickle cell: Gordon EM, Klein BL, Berman BW, et al. Reduction of contact factors in sickle cell disease. J Pediatr 1985; 106:427-30, and Miller RL, Verma […]

Do Plastic Tubes Affect INRs?

From Kim Kinney at Clarian: I got a call from an area lab that is having some issues with INRs. These are all being drawn in BD 2.7 mL plastic tubes. They are getting large discrepancies in INRs after an initial spin. They got a call from an ambulatory area questioning a 4.23 INR. When […]

Send-out Specimens

Hi George, I have recently taken over the duties of technical coordinator of our send-out department. This is a very large area with many reference labs. I am trying to standardize our specimen processing area since this seems to be one area where we have issues with sample quality. I was wondering if someone would […]

A “Wispy” Clot In a Manual PTT

A note from Beth Lewis: Hi George, I’ve just signed onto your site and so far am very impressed with its content. I’ll know I’ll refer to it regularly. Thanks so much for setting it up. I have a question for which I’ve been unable to find a good answer: When performing a manual test […]

Perform Staclot LA on TOP?

Kim Kinney of Clarian asks: Is anyone performing the Diagnostic Stago Staclot LA on the Beckman-Coulter TOPS analyzer?

ISTH SSC 2009 Updated Guidelines for Lupus Anticoagulant Detection

At the ISTH meeting in Boston I attended the July 11 Scientific and Standardization Committee on Lupus Anticoagulant, chaired by Vittorio Pengo, MD, of the University Of Padua School Of Medicine. Dr. Pengo and distinguished members of the committee presented an update of the Lupus Anticoagulant (LA) Detection Guidelines, first published in 1995. Their updates […]

PTT Reagent Sensitivity for FVIII & FIX

Here is a question from Fiona McCall at Siemens: Do laboratories investigate their normal PTT reference range routinely? I have concerns that laboratories try to determine the factor VIII & factor IX sensitivity of their PTT reagent without really knowing what is an abnormal PTT for their current PTT reagent lot number. Can anyone share with me the […]

Case Report: von Willebrand Disease

Here is a von Willebrand disease care report and summary prepared by Drs. Marisa Marques and Rebecca Cook from the University of Alabama at Birmingham Laboratory Medicine Department: lab-medicine-vwd-case-report-8-20-09

High-speed Centrifugation and PPP

An interesting question about centrifugation from Warren Varden, Tech Specialist of UAB’s special coagulation laboratory. Hey George: We are currently validating a stat centrifuge for routine coagulation testing. This centrifuge is marketed specifically for producing PPP in coagulation. It spins at 8,000 rpm with an RCF of 6,153. One of the techs questioned if such […]

More on Mixing Studies and the RVVT

Hi George, I have a further question about “Interpreting a prolonged PT and PTT,” posted April 16. My question is, “what if the PT and PTT are prolonged and correct upon mixing with normal reagent plasma, but the Russell viper venom time (RVVT) is normal?” This question is part of a coagulation project I’m doing […]

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George Fritsma is a medical laboratory scientist, educator, and author. George holds faculty appointments with Rutgers University and Michigan State University, and is a member of the International Society on Thrombosis and Hemostasis, American Association of Clinical Chemists, and American Society for Clinical Laboratory Science.

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