Platelet Function Testing

VerifyNow Platelet Function Screen?

Attached to the December 28 post, “Platelet Function Testing and the Bleeding Time” with the AC Ivy story was the question, “Is the Accumetrics VerifyNow aggregometer useful for screening patients for inherited platelet function disorders?” Yes, I consider the VerifyNow assay effective in screening for platelet function defects, like storage pool disorder or platelet secretion disorder (aspirin-like syndrome), however […]

Antiplatelet Therapy

Akers PIFA Kit

From Lynn Gingras, MT (ASCP), Rush-Copley Medical Center: Our institution is getting several complaints from the cardiologists as to the turnaround time of the heparin-induced platelet antibody (HIPA, heparin-induced thrombocytopenia with thrombosis, HIT, HITT) testing that we currently send out to a reference lab. Is there any value to bringing in the Akers Bioscience Particle ImmunoFiltration Assay (PIFA) […]

Arterial Thrombosis

Platelet Function Testing and the Bleeding Time

In 2009 Dave McGlasson and I published McGlasson DL, Fritsma GA, Whole blood platelet aggregometry and platelet function testing. Semin Thromb Hemost 2009;35:168–80. This article, the second-most cited in the 2009 Seminars in Thrombosis and Hemostasis, reminded me of our Quick Question about the Ivy bleeding time posted in early November, and subsequently lost when our site crashed […]

Bleeding Disorders

VerifyNow P2Y12 Assay: Change to PRU

I received this truncated communication on July 16 from Michael Suter with no follow-up, but I post it regardless, as Accumetrics’ decision to change their P2Y12 cartridge report seems to be a concern for many: “We monitor Plavix therapy using the VerifyNow P2Y12 assay kit. Accumetrics is in the process of discontinuing the reporting of percent inhibition, leaving the PRU […]

Antiplatelet Therapy

More on Aggregometer Validation

A big thank-you to Kathy Jacobs of Chrono-Log Corporation for her update on validation of aggregometry, added as a comment to

Platelet Function Testing

How to Validate an Aggregometer

From Rrosales: I am interested in purchasing a platelet aggregometer for our hematology lab, but we don’t have an existing instrument to compare it with. Some suggested H58 NCCLS (CLSI, does not really help) but I am used to validating an instrument with an old instrument (comparison/parallel testing). Can you tell me how to start the […]

Platelet Function Testing

Platelet Clumping in Sodium Citrate: Reprise

From Kathy Jacobs at Chronolog, Inc. Hi George, When a patient’s platelets clump in sodium citrate, is there another anticoagulant that can be used to allow LTA platelet aggregation testing? Thanx in advance, Kathy. Hi, Kathy, good to “hear” from you. You posted your question originally as a comment to a

Platelet Function Testing

Ristocetin: False Positives?

From Laurel Veek at Mayo Labs: We have noticed lately when performing platelet aggregations that more often than not we have a curve that is slow to develop but between 2-3 minutes it aggregates or has an abnormal slope if it aggregates before 3 minutes. Ideally I would like the curve to be relatively flat at […]

Platelet Function Testing

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

Freeze-thaw Platelets and Growth Factors

From “abi:” We freeze-thaw platelets and aliquot them in 50 mL tubes stored at –80°C. After this we process 2–3 rounds of freeze thaw cycles before using these platelets in MSC cultures. 1. My question is, can we process this 2–3 rounds of freeze thaw cycle in advance, say a month prior to use, for […]

Platelet Function Testing

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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