Factor Assays

Chromogenic Factor IX Assay

On May 9, 2022, Precision BioLogic, Inc. [PBI] announced the release and international approval for their chromogenic factor IX assay. Click here for PBI’s press release. The product addresses the key need for accuracy when monitoring extended half-life coagulation factor concentrate therapy.

Bleeding Disorders

November 2021 QQ: Case Study, Prolonged PTT, Response

Our November 2021 Quick Question Case attracted 75 responses. We asked, “A 3-YOA female with normal PT and prolonged PTT and no bleeding. What is the most likely deficiency?” Here are your responses: Factor V–3 [4%] Factor VIII–18 [20%] Factor IX–2 [3%] Factor XI–4 [7%] Factor XII–44 [59%] Factor XIII–4 [7%] Congenital factor V deficiency […]

Coagulation Factors

November 2021 Quick Question: Case Study, Prolonged PTT

Our November 2021 Quick Question involves a 3-year-old female patient with no bleeding history whose pre-op PT and PTT results were PT 13.3 seconds [RI 12-6–14.6] and PTT 51 seconds [RI 25–35] and asks what is the most likely coagulation factor deficiency. Please select your answer and add your comments below.

May, 2021 Quick Question: Flaujeac Factor Response

Our May, 2021 Quick Question was a historical factor name challenge, “What is the more common name for Flaujeac factor?” The question drew 24 responses. We answered: Hageman factor: 21% [5] Fletcher factor: 4% [1] Fitzgerald factor: 58% [14]X Stuart factor: 13% [3] Fibrinogen: 4% [1] High molecular weight kininogen [HMWK] was given the name […]

Extended Half-life FVIII & FIX and the PTT

From Carolyn McCarville: Hi George, My small laboratory is trying to figure out the best management of coag samples from patients receiving extended half life factor replacement products. We understand that many of the one stage clotting factor assays are inaccurate for the wealth of these products. One thing that we cannot get a straight […]

Bleeding Disorders

Covid and Lupus Anticoagulant

Two compelling publications appear to implicate lupus anticoagulant as a key factor in prolonged PTT results documented in seriously ill Covid victims. These could account for prolonged PTTs in the absence of hemorrhage. They are: Bowles L, Platton S, Yartey N, et al. Lupus anticoagulant and abnormal coagulation tests in patients with Covid-19. Downloaded from […]

New FVIII Inhibitor Assay

An exciting news release from Precision BioLogic Inc. Today, we are announcing the availability of our new CRYOcheck Factor VIII Inhibitor Kit in Canada, the European Union, Australia, and New Zealand following market authorization by Health Canada and respective in-country regulatory authorities in January. Click here for full information about the CRYOcheck Factor VIII Inhibitor […]

Bleeding Disorders

Quick Question: 6 YO Boy with Chronic Bleeding

Please click or tap our December 31, 2018 Quick Question post, a case study of a 6-year-old boy with chronic bleeding. We had a 2018–19 record 76 responses. The choices and responses are as follows. Answers Platelet function abnormality: 10 (13%) Von Willebrand disease: 14 (18%) Factor VII deficiency: 4 (5%) Factor XII deficiency: 4 […]

Bleeding Disorders

Nijmegen-Bethesda Assay

Beginning with a 2016 Quick Question and continuing to our most recent post in March, 2018, we’ve devoted altogether six entries to the 2012 CDC refinements of the Nijmegen-Bethesda assay. These have culminated in the following material, which appears in Fritsma GA, Chapter 41, Laboratory Evaluation of Hemostasis; in Keohane EM, Otto C, Walenga JM. […]

Bleeding Disorders

Quick Question: Extrinsic Pathway

Our September, 2018 Quick Question was a quiz with one correct answer addressing our knowledge of the coagulation cascade: Which coagulation factor is the first activated in the extrinsic pathway? With 144 responding, the answers were: Factor XII: 16 (11%) Factor IX: 9 (6%) Factor VII: 105 (73%) Prothrombin: 14 (10%) Congratulations to the overwhelming […]

Coagulation Factors

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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.

Cheat Sheets from George

Quick Question