Quick Question Archive

QQ Summary: Heparin Monitoring History

Results of our September, 2012 Quick Question: Historically, what assay was used to monitor heparin? a. Bleeding time: 14 (17%) b. Recalcification time: 7 (9%) c. Lee-White clotting time: 51 (63%) d. Thromboplastin generation time: 9 (11%) Participants need to be well-read, or “of a certain age” to answer this one. Bleeding time is incorrect. […]

Anticoagulant Therapy

New QQ: History

Our August and September Quick Question, posted Monday, August 27, is mostly for fun, and will appeal most to our more “seasoned” coagulationists. No wrong answer, just some more right than others! Please indicate the assay most often used before the partial thromboplastin time (PTT) for monitoring heparin.

Quick Question Archive

Quick Question Summary: VWF Activity

Here is a summary of our July, 2012 Quick Question: How do you assay for von Willebrand factor (VWF) activity? a. VWF ristocetin cofactor (VWF:RCo) by aggregometry: 21 (34%) b. Automated VWF ristocetin cofactor (VWFRCo): 21 (34%) c. VWF activity immunoassay (VWF:Act): 15 (25%) d. Collagen binding assay (CBA): 4 (7%) It seems the collagen […]

Bleeding Disorders

New Quick Question: VWF Activity Assays

There’s a definitive article in the June, 2012 JTH that describes the three methods currently available to assay von Willebrand factor activity: ristocetin cofactor (VWF:RCo), collagen binding (VWF:CB), and a monoclonal antibody-based immunoassay (VWF:Act). See Favaloro EJ, Bonar R, Chapman K, Meiring M, Funk (Adcock) D. Differential sensitivity of von Willebrand factor (VWF) ‘activity’ assays to large […]

Bleeding Disorders

QQ: Anti-Xa Heparin Assay

Here’s a summary of our June, 2012 Quick Question: To perform the chromogenic anti-Xa heparin assay, how many separate reference curves do you maintain for unfractionated (UFH), low molecular weight (LMWH) heparin and fondaparinux? a. One hybrid curve for UFH and LMWH, same curve (computed) for fonda: 7 (16%) b. One hybrid curve for UFH […]

Anticoagulant Therapy

QQ: Reflexing POC INRs

Here are the responses to our May, 2012 quick question: When using point of care testing, at what INR does your anticoagulation clinic require a confirmatory plasma-based (conventional) PT? a. 4.0: 34 (65%) b. 5.0: 9 (17%) c. 6.0: 4 (8%) d. Never: 5 (10%) Our responses closely parallel our April 24 and May 7 discussions; […]

Anticoagulant Therapy

Quick Question Summary: LDTs

Here is a summary of our April, 2012 Quick Question: The US FDA is planning guidelines for regulating laboratory-developed tests (LDTs). What plans have you made in response? a. We are discontinuing all LDTs: 3 (15%) b. We didn’t know this is happening: 11 (55%) c. None, this will only apply to reference laboratory LDTs: 1 (5%) […]

Quick Question Archive

Quick Question: Heparin Therapeutic Range

On October 21 I posted my

Anticoagulant Therapy

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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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