In follow-up to Cassandra McGeachy’s August 7 question on the euglobulin lysis time (ELT), I’ve found two references for upgraded ELT methods that may be helpful.They are:
- Cellai AP. Lami D, Magi A, et al. Assessment of fibrinolytic activity by measuring the lysis time of a tissue factor-induced clot: a feasibility evaluation. Clin Appl Thromb Hemost 2010;16:337–44.
- Smith AA, Jacobson LJ, Miller BI, et al. A new euglobulin clot lysis assay for global fibrinolysis. Thrombos Research 2003:112:329–37.
From friend and colleague Cassandra McGeachy, Louisiana Coagulation Laboratory,
Hi George, I am looking for procedures available for performing the euglobulin lysis time (ELT). I am looking to update my present method if there are any options available.
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George, This is not really a coag question but relates to an issue we see intermittently in our clinical lab. It is the problem of receiving clotted body fluid specimens with the request of a cell count to be performed. While educating the clinician to put the specimen in an anticoagulant tube is ideal to avoid this problem, we do get these requests at times. Since the specimen is not easily recollected, we do not uniformly reject them but do the analysis with a disclaimer. I was wondering if you had any experience or have heard of anyone actually introducing a fibrinolytic agent to break up the clot to be able to perform a more useful evaluation? I remember back in my med tech days that we used to add protamine sulfate to dialysis patient specimens to activate the tubes to clot and wondered if anyone has thought of doing the opposite in these clotted body fluid specimens. I appreciate your thoughts on this question. Thank you in advance. Dr. Bruce King.
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Here is a note from the American Society for Clinical Laboratory Science Consumer Web Forum: What is the normal value of D-dimer in pleural or peritoneal fluids. I know the normal range of D-dimer in the blood is less than 250 ng/mL D-Dimer Units but what about other body fluids? Thank you.
I have found no reference to D-dimer assays in body fluids except for two primary research publications that record coagulation components in tumor-related exudates. Do any of our participants have any experience with this?
From Pam Owens, Centennial Medical Center, Nashville, TN. Recently a pediatric group approached us asking if we would do a fibrinogen level on pleural fluids before and during administration of tissue plasminogen activator (TPA, Alteplase) for resolution of the effusion. I found the previous reference to this treatment in a post from August 2012, but no mention of a fluid fibrinogen level. So my question is threefold:
1 What is the utilization for this?
2 Does anyone else have experience with this request?
3 Would you put a potentially viscous sample on an instrument or would the test have to be performed some other way?
We are scheduled to meet with the pediatricians when they all return from the holidays, but would like some perspective.
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From Ning Tang: Hi, George, I come from a clinical laboratory in China. We met a confusing case today and want to get your suggestion: A patient had a prolonged prothrombin time (PT, 20s), partial thromboplastin time (APTT, PTT, 52s) and thrombin time (TT, 127s). Fibrinogen activity is within reference interval (by both Clauss method and TEG), also the patient shows slight bleeding symptoms, is this dysfibrinogenemia? How to confirm it? Thanks for your help!
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From Suakimi Pouhila, Auckland District Health Board, New Zealand. We have a patient which showed high D-dimer results with Siemens’ Innovance D-dimer but normal Stago D-dimer results. Has anyone seen this before? Is this due to cross reaction with a heterophile antibody?
Hello, Suakimi Pouhila, and thank you for your question. The various monoclonal antibodies that are employed in the D-dimer assays by manufacturers all have slightly different targets, thus there are often discrepancies among results, as illustrated by the variance in results of external quality assurance programs. However, the degree of discrepancy that you describe is unusual. I’ve contacted my US acquaintances at Siemens and Stago to learn if they have any insight.
From Michael Suter, MT (ASCP) SH Senior Clinical Scientist, Hematology, Peace Health Laboratories, Springfield, Oregon.
George, I am curious about your thoughts on how to best address the effect of high hematocrits (HCTs) on the quantitative latex D-dimer assays such as the Stago D-Di test. With high HCT samples, there is a relative decrease in plasma causing a relative excess of anticoagulant. With prothrombin time (PT) and partial thromboplastin time (PTT, APTT), it’s necessary to redraw the patient into a tube with a decreased amount of anticoagulant to normalize the plasma:anticoagulant ratio. You can’t simply correct mathematically for the excess anticoagulant, because the effect is more than dilutional and the test may end up measuring citrate anticoagulation instead of just the in vivo patient anticoagulation. Empirical studies were required to show that high HCT becomes significant above 55%.
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