Lupus Anticoagulant

Prolonged DRVVT Screen

Soha Abuelela asked how to report a DRVVT screen above 120 seconds and how to report the ratio. I [Geo] consulted with my colleague Dave McGlasson. We began by assuming that 120 seconds represents your instrument’s limit and that the actual clotting time was unrecorded. It could be that your specimen has an undetected clot […]

Anticoagulant Therapy

Is DRVVT Normalization Necessary?

The clot-based dilute Russell viper venom test (DRVVT) reagent activates the coagulation mechanism’s common pathway at the factor X (10) level, relying only on factor V, prothrombin, and fibrinogen for clot formation. The DRVVT test complements the PTT-based assay for lupus anticoagulant (LAC) detection. Because LAC is phospholipid (PL)-dependent, both assays use a minimal-phospholipid (PL) […]

Testing for the Lupus Anticoagulant: The Good, the Bad, and the Ugly

Click here for a “State of the Art Review,” Favaloro EJ, Pasalic L, Selby R. Testing for the lupus anticoagulant: The good, the bad, and the ugly. Research and Practice in Thrombosis and Haemostasis 2024; 8: DOI:https://doi.org/10.1016/j.rpth.2024.102385.

Interpreting Inhibitor Mixing Study in a Hemophilia A Patient

I [Geo] received a physician’s question on 1-31-24: Dear Sir, Hope you are doing well. Thank you for creating this platform and sharing valuable resources with the world. We present a case of Hemophilia A with recent retroperitoneal hematoma and multiple transfusions–PRBC, FFP, Factor VIII, and NovoSeven. APTT of Test Plasma: 47 seconds [RI 22.2–33.1 […]

Precision BioLogic Poster at ISTH: DOAC-Remove

You are invited to visit the ISTH poster submitted by Precision BioLogic Inc.: PB1147 Effect of high-dose direct anticoagulant drugs and DOAC-Remove on lupus anticoagulant detection by a hexagonal phase phospholipid assay. The poster goes up Tuesday, 27 June 2023, 18:30–19:30.

Specimen Management

Familial APS?

On June 1 a Fritsma Factor participant asked if there were any evidence of a familial prevalence for symptomatic antiphospholipid syndrome [APS] or lab evidence for the familial distribution of one of the antiphospholipid antibodies [APAs]: lupus anticoagulant [LA], anti-cardiolipin antibody [ACA], or anti-beta-2-glycoprotein 1. I [Geo] located only a single case report: Bhattacharya S, […]

Lupus Anticoagulant

Antiphospholipid Antibodies in Gulf War Syndrome

Thanks to hemostasis researcher Dave McGlasson for sending this article that indicates lupus anticoagulant as an autoimmunity mechanism associated with Gulf War Syndrome. James LM, Johnson RA, Lewis SM, et al. Lupus anticoagulant in Gulf War Illness and autoimmune disorders: a common pathway toward autoimmunity. J Immunological Sci. 2021; 5: 14–18. Dave had published a […]

August 2022 Quick Question: LAC Testing Responses

Our August 2022 Quick Question attracted 34 responses [despite our discouraging “Recaptcha” security function] and asked, “You test for lupus anticoagulant [LAC] using a low-PL PTT reagent and a hex-phase high-PL mix. The mix results are 10 seconds shorter than the first test. What do you conclude?” LAC positive 32% [11] LAC negative 18% [6] […]

Lupus Anticoagulant

August 2022 Quick Question: LAC Testing

Our August 2022 Quick Question addresses lupus anticoagulant testing, a member of the standard thrombophilia screening profile. “You test for lupus anticoagulant [LAC] using a low-PL PTT reagent and a hex-phase high-PL mix. The mix results are 10 seconds shorter than the first test. What do you conclude?” The question illustrates the PTT-based LAC test […]

Lupus Anticoagulant

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 […]

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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

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