Specimen Management

Sodium Citrate: 3.8%?

A contributor asks, “has sb reported shorter clotting times when using 3.8% (0.129M) sodium citrate tubes than 3.2% (0.109M) tubes? literature and the logic says the opposite.” Hello, and thank you for your question. I’m unsure of your reference to “sb,” however I agree that it is logical to presume that the 3.8% sodium citrate […]

Screening Assays

Hemostasis Specimen Management

I am trying to find a chart or article that tells how long plasma is good for hemostasis testing. The question has arisen about fresh samples and frozen samples. We often get requests for add-on tests and need to know how long is too long. Do you know of a resource that will provide this […]

Specimen Management

Overfilled Tubes

Here is a question originally posted November 4, 2011 that did not attract discussion at the time: I received a note from David Chance, Good Samaritan Medical Center, Corvallis OR, commenting that, unlike underfilled coagulation specimen (blue-closure) tubes; overfilling tubes, unless clots are present, does not affect coagulation results. Overfilling may occur when a specimen is […]

Specimen Management

Specimen Freezing and FVII Activation

Oiginally posted on October 25, 2011. From Kim Kinney at Indiana University (formerly Clarian) Health Center: Hi George, Even though I am not in coag much any more I still get a ton of questions. One of our TC’s was questioning our storage of PT/INR specimens. We follow the current recommendations of room temperature for 24 hours. […]

Specimen Management

Last Word on ACD Tubes for Platelet Satellitosis

Actually, nothing on this site is the last word, however I contacted Dennis J. Ernst, MT (ASCP), Center for Phlebotomy Education, about Donna Kaiser’s 4/5/13 acid-citrate-dextrose (ACD) tube question. Dennis’s response is: “Nice to hear from you. I haven’t heard anything about the use of ACD tubes in this context. I wonder if a tube manufacturer would shed […]

Specimen Management

ACD Tubes for Platelet Satellitosis

From Donna Kaiser, St. Joseph Health System: I was wondering if you have any information on using acid citrate dextrose (ACD) tubes for EDTA platelet clumpers. I have heard they may work better than the sodium citrate tubes especially for oncology patients. If so, are Sol A or Sol B tubes being used and is there a […]

Specimen Management

High HCT and PT, PTT, and D-dimer

From Barbara Robinson, MT (ASCP), Children’s Hospital of New Orleans, If a sample is tested for D-dimer, prothrombin time (PT) and partial thromboplastin time (aPTT, PTT), and the anticoagulant in tube has not been adjusted for high hematocrit (HCT = 60.8%), what tests would be invalid, and how would results be affected? Hi, Barbara, and thank you […]

Screening Assays

Bleeding After CABG: Heparin?

Here is a puzzling case sent by Crystal Azevedo: Hi George! I have a question for you from one of my pathologists. 24 hours after an uneventful coronary bypass procedure a 51 kg patient developed acute hemorrhage. A post-protamine thromboelastogram (TEG) on the day of surgery was completely normal. At the time bleeding occurred, the patient […]

Anticoagulant Therapy

Tube System and Heparin

The subject of tube system hemostasis specimen delivery originally appeared on theMedlab_L list, and I asked Linda Stang, Lab Scientist in Special Coagulation at theUniversity of Alberta Hospital in Edmonton for permission to share her Medlab_Lcomment. She wrote, “Our hemolysis rate for those patients is much higher and we are engaging in a plan to figure it out. The […]

Specimen Management

Specimen Tube “Head Space” and pH

A colleague asked about an issue with “head space” and surface area in sodium citrate (blue-closure) tubes causing changes in pH with the changes becoming more profound the longer the tube is stored. This then affects test results. My friend had not heard of this before although he knows there are pH changes associated with […]

Specimen Management

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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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