From Kelly Townsend at Tricore Labs: We have a patient whose platelets clump in every anticoagulant we’ve tried. He has normal prothrombin time, partial thromboplastin time, fibrinogen, and von Willebrand disease panel results, but oozes after even minor procedures. The clinicians want to evaluate platelet function, but we are hesitant because of his platelet clumping. Any suggestions for obtaining accurate platelet function analyzer (PFA-100) and/or platelet aggregation results in a platelet clumper? We use theChrono-log Lumiaggregometer (whole blood).
Hi, Kelly. This appears to be a pathological situation and not simple platelet satellitosis, and I doubt that while platelets are clumping that you will be able to generate a reliable aggregation response. You don’t list the anticoagulants that you’ve tried, but I assume they include the acid-citrate-dextrose (ACD) and the citrate-theophylline-adenosine-dipyridamole (CTAD) tube. Platelets may function in the former, however aggregometry is not validated on the ACD tube. The CTAD tube shuts down platelet function altogether and may work for generating an accurate platelet count, but not aggregometry. I once heard a talk from platelet expert James George MD in which he asserted that in unexplained thrombocytopenia, l
A laboratory in New York also experienced platelet clumping.
A laboratory in New York also experienced platelet clumping. Decided to keep EVERYTHING at 37oC … cuvettes, stir bars, tubes, probes, pipette tips and sample. Sample still clumped !
You may check this report:
Pseudothrombocytopenia observe
You may check this report:
Pseudothrombocytopenia observed with ethylene diamine tetra acetate and citrate anticoagulants, resolved using 37°C incubation and Kanamycin
http://www.ijpmonline.org/article.asp?issn=0377-4929;year=2013;volume=56;issue=3;spage=306;epage=308;aulast=Kamath
when I was reading this…I wondered if the samples would be
when I was reading this…I wondered if the samples would benefit from being held at 37C from the time of collection through to testing ? a control run in the same manner would be a necessity, but thought that it might offer some level of “platelet un-clumpiness”. has anyone ever tried this ?
In theory, aminoglycosides added to the tube prior to blood
In theory, aminoglycosides added to the tube prior to blood collection could prevent PLT clumping if other anticoagulants failed. A recent paper suggested that kanamycin did not affect PLT aggregometry (at least by ADP): Clin Appl Thromb Hemost. 2012;18:538-41. The effects of aminoglycoside antibiotics on platelet aggregation and blood coagulation. Chen G, Fei X, Ling J.
OBJECTIVE: To investigate the effects of different aminoglycoside antibiotics on platelet aggregation and blood coagulation, as well as the underlying mechanisms.
METHOD: Blood samples were collected and prepared as platelet-rich plasma and platelet-poor plasma samples. Then assigned into different groups for the following antibiotics treatments: gentamicin, streptomycin, etimicin, amikacin, and kanamycin, as group 0 mg/L, group 30 mg/L, group 91mg/L, and group 910 mg/L for each drugs. The maximum platelet aggregation rate induced by adenosine diphosphate, expression levels of CD62p and FIB-R, prothrombin time, activated partial thromboplastin time, thrombin time, and fibrinogen were measured. The sodium citrate and sodium heparin were used in whole blood tests for the whole blood coagulation time as well as the Ca(2+) in blood plasma.
RESULTS: Amikacin and gentamicin could inhibit the aggregation of platelets, which contributed to the whole blood clotting disorder.
CONCLUSION: Amikacin and gentamicin might inhibit the platelet aggregation by blocking the activation and release of FIB-R or probably the inhibition of endogenous clotting factor as well. This effect was not dependent on calcium ions.