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Local ISI (or INR) Calibration

It seems strange North American coagulation laboratories have not adopted local ISI or INR calibration despite articles such as Poller L, Keown M, Ibrahim S, et al. Comparison of local International Sensitivity Index calibration and ‘direct INR’ methods in correction of locally reported International Normalized Ratios: an international study. J Thromb Haemost 2007;5:1002-9 and Adcock […]

More on Arixtra Monitoring

A post from Bryan McGill, PharmD at St. Mary’s Hospital in Madison, WI: We have a patient with a history of HIT, so we are using Arixtra 2.5 mg q24h for prophylaxis. Unfortunately the patient also has a CrCl hovering at 30mL/min, so I am worried that the drug may start to build up. Are […]

Checking for Clots

We check all citrate specimens for clots by probing them with applicator sticks before centrifugation. Is this common practice? Are there alternatives?

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 […]

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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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