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Monitoring Plavix using the PFA-100

Here is a question about the bleeding time from Sue Hillyard: I was recently asked to perform a bleeding time on a patient who was on Plavix. The reason for this was that the “PFA is insensitive to Plavix, the bleeding time is more sensitive.” Is this technically correct? If so, why? Hi, Sue. You can monitor […]

Factor XII Reduction in Sickle Cell Anemia?

Our UAB coagulation lab specialists have noticed a series of prolonged PTTs associated with reduced factor XII in specimens from our sickle cell patient clinic. We found one 24-year old reference, Gordon EM, Klein BL, Berman BW, et al. Reduction of contact factors in sickle cell disease. J Pediatr 1985; 106: 427-30, that documents a significant […]

Critical INR Value: Follow-up

I’m a little behind on my reading and just saw an excellent September 2008 CAP Today Q&A by Dr. John Olson on critical values for prothrombin time (PT) coumadin monitoring. In our Quick Question on the subject we didn’t include the option some laboratory managers select, which is to assign the critical value to the PT result […]

Quick Question: Unfractionated Heparin Management

The results of our December 20 Quick Question are a little surprising: How do you produce your PTT therapeutic range for monitoring unfractionated heparin? a. Spike a normal plasma with measured heparin and perform PTTs: 6 (32%) b. Use 1.5 to 2.5 X the mean of normal: 1 (5%) c. Brill-Edwards ex-vivo curve using anti-Xa […]

ISTH XXII Congress Boston July 11-16, 2009

I posted an announcement last October (2008) regarding the biennial ISTH meeting in Boston, and just wanted to remind you of the February 28 early registration deadline. I look forward to seeing you in Boston.

Ehlers-Danlos Syndrome

A question about Ehlers-Danlos syndrome from Dr. John McClure: I was asked by a hematology colleague about bleeding risk in an Ehlers-Danlos patient. He was consulted for a preoperative assessment. The patient has a “self-reported” history of bleeding but has undergone uneventful lap-chole and vaginal deliveries. My colleague is specifically asking about the PFA 100 […]

Case Study: 26 YO Female with Chronic Bleed

Here is a case sent by Ashli Jarrell, an articulation student in the University of Cincinnati online CLS program. I will leave the answer open for a few days to get your opinion: Hi, George. I have an interesting case: 26 YO female. History: nosebleeds since age 3; age 5 tonsillectomy with increased bleeding post-op; age […]

PFA-100 Prolonged CTs in Children

Here is a new stumper from Kim Kinney at Clarian in Indianapolis: Hi, George. We perform many PFA-100s on both adults and children. We have started seeing a pattern only in children. Approximately six times in the past few months, we have seen abnormal EPI and ADP closure times with totally normal platelet aggregations. We […]

Bleeding and Elevated Factor VIII

Our coagulation lab specialists at UAB have noted anecdotally that long term bleeding is accompanied by elevated factor VIII activity levels. Have others seen this, and is there a reference documenting it? Geo.

Heparin Therapeutic Range

Here is a question on how to develop the PTT therapeutic range using the Brill-Edwards method in a low-volume facility. This is from Michael D. Blechner, MD, Assistant Professor of Pathology and Laboratory Medicine, University of Kentucky Medical Center: George, Here at UK (University of Kentucky) we use plenty of unfractionated heparin (UFH) and it […]

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George Fritsma is a medical laboratory scientist, educator, and author. George is a member of the International Society on Thrombosis and Hemostasis, the International Society for Laboratory Hematology, and the American Society for Clinical Laboratory Science.

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