Combined Factor V and VIII Deficiency

The July issue of Clinical Chemistry presented a well-written case of combined factor V and VIII deficiency: Khani F, Roshal M. A 24-year-old man with previously diagnosed hemophilia. Clin Chem 2012;58:1086–90. Drs. EM Van Cott and JN Huang added commentaries. I noted the recommendation for plasma to replace factor V and posed this question: Dr. Khani, thank you […]

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Bleeding Disorders

Jul 12 2012

george

Monitoring Factors after Plasma Administration

From “japgi.” Hi! I’d like to get some information (if possible a reference) on this clinical situation. If a patient with an uncharacterized bleeding disorder has been transfused plasma or cryoprecipitate in an emergency setting, how soon afterwards can one do a coagulation screen to avoid the results from getting compromised by the transfused factors? […]

Bleeding Disorders

Bethesda Titer Protocol

Hello George! Our laboratory would like to start offering the factor inhibitor assay (Bethesda titer). We currently do special coagulation tests for several hospitals and clinics. I was wondering if there is a procedure you are willing to share. Sincerely, Maria E. Martinez, BS MT (ASCP), Senior Medical Technologist–Coagulation, Orlando Regional Medical Center. Hello, Maria, and […]

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

Undiagnosed Thrombocytopenia

From an anonymous inquirer: I have been misdiagnosed for years. I have very large and oval-shaped platelets which my average count is 40,000. I also tell whoever is taking my complete blood count (CBC) to make sure it is a manual count because my platelets are too large for the machine. I have great coagulation […]

Bleeding Disorders

PRP Gel, Platelet Substitute

Another interesting discussion from our UMDNJ graduate Hemostasis course: About 6 years back, I caught wind of a discussion regarding platelet substitutes, which I found quite intriguing. I did some digging as a result of this discussion and am amazed by the potential of such technologies. It appears that platelet rich plasma (PRP) gel has been around […]

Bleeding Disorders

Ristocetin Cofactor

Laura Lum, Seattle Children’s Hospital, asks, What is the ristocetin cofactor assay for, how is it performed, and can it be done on an STA Compact? Hi, Laura, the ristocetin cofactor assay is a test for von Willebrand factor (VWF) activity. Low VWF is the cause of von Willebrand disease (VWD). The assay began as platelet aggregometry […]

Bleeding Disorders

New Ristocetin Lot and Storage Requirements

We’ve had two questions about Ristocetin since our 11.9.11 Problems with Ristocetin question from Kerri Klemm. Kerri’s question prompted me to contact Kathy Jacobs at Chrono-log Corp, a major distributor of ristocetin in the US and around the world. Here is a follow-up message from Kathy: Hello George, Nice to hear from you and a very happy New Year to you and your family. As […]

Bleeding Disorders

Adapting Ristocetin Cofactor Assay Reagent

Has anyone been able to adapt a third-party reagent for ristocetin onto a Stago STAR-E or Compact? If so, would you be willing to share your experience with the product, validation procedure, etc? Please feel free to reply off-line if you so desire, and thank you in advance, Dorothy Zdanowicz, Chemistry/Coagulation Supervisor Englewood Hospital & […]

Bleeding Disorders

Acceptable Interval for VWF:RCo

George, Our lab participates in both CAP CGE and NASCOLA ECAT proficiency challenges. One of those assays, von Willebrand factor ristocetin cofactor (VWF:RCo) activity by the agglutination method, is difficult to judge in terms of performance. When looking at results, what is acceptable for criteria? I usually look for ±2 SD for other tests. Sometimes […]

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Bleeding Disorders

Bleeding Disorders

Combined Factor V and VIII Deficiency

Monitoring Factors after Plasma Administration

Bethesda Titer Protocol

New Quick Question: VWF Activity Assays

Undiagnosed Thrombocytopenia

PRP Gel, Platelet Substitute

Ristocetin Cofactor

New Ristocetin Lot and Storage Requirements

Adapting Ristocetin Cofactor Assay Reagent

Acceptable Interval for VWF:RCo

George Fritsma MS MLS

Cheat Sheets from George

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