Specimen Management

Whole Blood PTTs

From Kirk Guyer, Cascade Technologies: There are whole blood PTT (APTT) assays and there are citrated platelet poor plasma (PPP) PTT assays. What happens in a PPP PTT assay if there are platelets present? Does the PTT result shorten? Can platelets shorten the PTT result in a whole blood PTT assay? I ran a PTT […]

Bleeding Disorders

Bangor Presentations

George was in beautiful Bangor, Maine, Monday, September 12, where he provided two presentations for regional medical laboratory scientists, sponsored in part by Dahl-Chase Diagnostic Services. Handouts for George’s talks are provided below. Please click or tap if you would like to have the handouts. Measuring the DOACs, Whatever Happened to the PT and PTT? […]

Anticoagulant Therapy

New Quick Question: Hemolysis

Please check out and answer our new Quick Question, “How do you manage hemostasis specimens with visible hemolysis?”

Quick Question Archive

Specimens with Hematocrit >55%

From Michelle Fahs, MT (ASCP), Clinical Laboratory Educator, Mercy Hospital St. Louis School of CLS. George, Do you have any recommendations on how the sample should be collected for coag testing if the patient’s hematocrit is >55%? We have in our policy the formula and procedure for adjusting the amount of anticoagulant in the tube […]

Specimen Management

Platelet Clumps on Blood Film

Susan Lemire asks, “Hi, what are most people doing when platelet clumps are found on the blood smear, but the platelet count is within normal range?” Hi, Susan, my hunch is that since we don’t review blood films when the CBC is within acceptable parameters, we probably miss some platelet clumping. CBC profiling instruments do […]

Platelet Function Testing

Clotted Knee Fluid Cell Counts

From Susan Lemire: We received a solidly clotted knee fluid, with minimal non clotted blood. How do others handle these as far as reporting cell count and differential? From George: I’m not certain this approach would resolve your situation, but we treat synovial fluid with hyaluronidase to liquify the clot-forming hyaluronic acid before counting. I […]

Specimen Management

Fibrinogen Storage Stability

From Susan Lemire, can you confirm that the specimen stability for measuring fibrinogen is 24 hours? Thanks. Hi, Susan, the attached Scientific Reports article (a Nature publication) gives specimen stability for several coagulation factors and assay results. The study seems conclusive, as the authors used a sufficient sample of 72 specimens and referenced several additional […]

Specimen Management

Correcting for Hypothermia

From Carla Purvis, MT (ASCP) SH, Parkview Regional Medical Center in Fort Wayne: Hi, George. We have acute care clinicians requesting temperature correction for prothrombin time results for patients who have clinically induced hypothermia. CAP standards state prothrombin times must be performed at 37C. Do you have any references for performing temperature corrections? Thanks. Hi, […]

Bleeding Disorders

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

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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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