Posts

D-dimer Reporting Discrepancies

Ms. Denise Broadbent, Laboratory Supervisor at Klickitat Valley Hospital in Goldendale WA posted a question to Medlab-L I will summarize here, followed by a clear discussion from Warren Coffin of Crozer Keystone Health System: Recently we ran a D-dimer, getting a result of >700 ng/mL (negative <230, normal up to 255 ng/ml). The patient was […]

Linearity

Here is a question from Kim Kinney at Indiana University Medical Center: I have a question regarding linearity in coagulation. Since most of our special coag assays are based on standard curves, can you not say that an assay is linear from the low to high standard? If you want to extrapolate beyond the low […]

ASH Meeting: New Oral Anticoagulants

Two new oral anticoagulants are emerging from phase III trials and receiving attention at this year’s American Society of Hematology annual meeting, in progress in Atlanta, GA. These are… Dabigatran, Boehringer-Ingelheim, a direct thrombin inhibitor, and Rivaroxaban, Bayer, a Xa-inhibitor. Both appear to possess safety and efficacy profiles equivalent to low molecular weight heparin, and […]

Platelet Clumping in Sodium Citrate

Dan Heidemann, MT (ASCP), Oncology Alliance, Milwaukee, WI wrote this question to Medlab-L on Tuesday, December 4. He gave me permission to post it here: Most people have heard of spontaneous platelet clumping in EDTA, but what if they also clump in a citrate (blue top) tube? Thanks! Dr. Mario Kyriacou provided this response also […]

Two Additional New Modules

We’ve posted two additional new modules, Clinical Efficacy 1 and Clinical Efficacy 2. These address computation of false positives and negatives, clinical sensitivity and specificity, predictive values, and ROC analysis. They’ll soon be linked to their respective CACMLE quizzes. Geo.

Antithrombin Deficiency and INR

Cristina Granada asks, does antithrombin III deficiency (type 1) affect the INR? My antithrombin levels came back low but my INR came back at 1.17. Thank you for your question, Cristina. Antithrombin (also called AT, antithrombin III or ATIII) deficiency does not affect the INR result, and in fact, an INR of 1.17 falls within […]

Aspirin and a Low Platelet Count

I received the following message from “Sumaya:” Can a patient with a low platelet count be treated with aspirin? Thank you for your question, Sumaya. Typically, physicians counsel patients to avoid aspirin if they experience a bleeding disorder. For example, if someone with a low platelet count finds multiple bruises or experiences nosebleeds or excessive […]

Two New Modules

Our newest continuing education modules, Method Validation 1 and Method Validation 2 were posted today, November 20, 2007. Please have a look and if you have any questions, contact me through “Ask George.” I hope you enjoy the modules. Geo.

Why all the PTTs?

It seems that many North American institutions are moving more and more to the use of low molecular weight heparin… …(mostly Lovenox in the US) and pentasaccharide (Fondaparinux, Arixtra) in place of standard unfractionated heparin. Yet, the lab volume of partial thromboplastin time (PTT, APTT) tests seems to be holding steady. What are all those […]

Intravenous Lovenox and PTT: Response

In response to Dana Haas’ question about IV Lovenox (Enoxaparin, low molecular weight heparin, LMWH) and the PTT, while it is true the PTT is relatively insensitive to LMWH, it is slightly prolonged. According to Lovenox Prescribing Information, a standard IV bolus of 30 mg followed by a 1 mg/kg SC injection results in a […]

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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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