Specimen Management

PNP: How Many Donors?

From Dr. Tang: Dear George, In the mixing test, commonly 20 healthy donors is required for preparing normal pooled plasma, why not 15, 10, or 5 donors? Have any studies validated that? Thank you for your reply. Hello, Dr. Tang. I know of no published studies that establish 20 donors as a minimum for producing […]

Specimen Management

EDTA Vs. Citrated PLT Count

From Susan Lemire, Elliot Hospital, New Hampshire Hi George, I am validating the new Sysmex XN analyzer and they do not support a citrated platelet count for clumped platelets. In order to continue our current process, I am in the midst of doing a correlation between EDTA platelet counts vs. citrated counts. I have found […]

Platelet Function Testing

Anti-Xa Result is Zero

From Jennifer Watson, Centracare Health: Hello, What are your recommendations when an anti factor Xa returns with a value of 0, even after increasing doses several times? Thank you. Hello, Jennifer, and thank you for this question. Assuming the heparin dosing has been administered correctly, you may be seeing a patient who has acquired, or […]

Anticoagulant Therapy

Lipemia Statistics

Hi George, If I want to show the effect of lipemia on coag test before and after spiking a single sample, is the % difference between the baseline and spiked results enough? How do you show whether there is a statistical or clinical difference, and what stat tool to use? Thanks, Marc. Hello, and thank […]

Specimen Management

Platelet Count on Spun Blue-top

From Tiffany Jones, Orlando Health: I was wondering if you could clarify for me why we can’t use a blue citrate tube for a platelet count after it has been spun once. Are there any studies to back up this reason? My facility seems to get a fair amount of patients displaying EDTA-induced platelet clumping […]

Specimen Management

HCT >55% and Citrate Volume Adjustment

George, is there research available now that states a HCT >55% will not interfere with PT or PTT results? We struggle with the CAP requirement. We use a mechanical based method for PT and PTT within our organization. Hello, and thank you for your question. The current CLSI guideline, Adcock DM, Hoefner DM, Kottke-Marchant K, […]

Screening Assays

Effect of HCT on POC INR

George received this question from the ASCLS Consumer Web Forum via Bonnie Jo Taylor, MHS, MT(ASCP)SH. I have hemochromatosis, too much iron in my blood. I’ve also had blood clots in my lungs. I peroidically undergo phlebotomy treatments to lower iron count. Will this alter the results of my INR finger prick test results? Here […]

Anticoagulant Therapy

Collecting Heparin Assay Specimens from a Device

Dear George Fritsma, I work at The Valley Hospital in Ridgewood N.J. and our nursing staff has the following question about drawing an APTT from a central line/picc line when heparin is infusing. Is there a protocol of how long to stop the infusion? Also, should the first syringe be discarded? I am interested in knowing […]

Anticoagulant Therapy

Coagulation Testing on an EDTA Specimen

Hi George: We encountered a case recently where we were asked to perform coagulation testing on specimens collected in EDTA vacutainers. The patient was refusing to give more blood than already collected for further coagulation tests and the attending doctor requested us to perform the tests in the blood collected in EDTA vials. We refused […]

Specimen Management

Correction for HCT >55%

Joan Chapman sent this question. Our institution corrects for HCT greater than 55% for routine and special coagulation assays. It has been our observation, however, that occasionally a patient sample will have a normal PT and PTT in spite of a high crit. We have had a policy that states if the PT and PTT […]

Screening Assays

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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.

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