This message came to George via Elaine Benoit, Precision BioLogic Inc. Good evening Mr George, I accidentally came across the site and I am very happy to have found you. First of all I apologize for English. I am passionate about in vitro haemostasis. In December 2013 I thought and applied a post-analytical sample clotting procedure that we are using at this time, being effective. We have never used an applicator on the real reason that before centrifuging we are not allowed to “look” in the sample. And then it’s relative to find the little clot that can not get caught by the applicator. I would feel honored to join you to share this procedure, as well as the reasoning of your need. With great respect, Carmen Delianu.
Hello, Dr. Delianu, and thank you for your question and your offer to share your procedure. For assistance, I forwarded your question to my colleague and friend, Dennis Ernst, Center for Phlebotomy Education. Here is Dennis’s response:
If I understand it correctly, Carmen Delianu is wanting us to suggest a procedure on removing clots from tubes without an applicator stick. I agree with Carmen that using an applicator is a bad idea for many reasons. However, I think the only substitute is to prevent the conditions that make it necessary to remove a clot in the first place. Of course, the presence of clots in a coag tube render the sample unusable for testing, so it’s pointless to take them out.
The conditions that cause clots to form in coag tubes include overfilling, inadequate mixing, allowing blood to remain in a syringe too long before transferring, and using expired tubes. There may be more, but those are the ones that come to mind. If we took an educational approach to teach our staff about these causes, we’d probably have fewer clots and better samples. So I think the only real answer is to be proactive to prevent clots in the first place. Taking a reactive approach to remove the clot is inadvisable.
To expand on Dennis’s comment, my institution discontinued the use of applicator sticks to check for clots several years ago, mainly because the process introduced the risk of viral transmission through exposure to blood. In addition, our test volume precludes the possibility, it would slow our processing drastically. Also, two years ago we moved to automation, which makes it almost impossible to check every specimen. We make every effort, as Dennis recommends, to educate our blood collectors on proper specimen management technique, and in addition, we review any suspicious coagulation test results. I hope this is helpful.
We still check every sample
We still check every sample that comes through both routine and special coag labs for clots using applicator sticks (except platelet function testing). Even with the newer instrument advances, we feel that human hands and eyes are necessary with respect to this aspect of specimen integrity. I have been collecting data, trying to find a pattern in results from clotted specimens. The scariest example was a heparinized patient – results from the clotted sample were completely normal, no indication of false results. The redraw had a PTT in our therapeutic range, as one would hope for. Our pathologist is sticking to his guns on this, but we recognize that we are a dying breed and may be fighting a losing battle.
Hello, Dr. Favaloro, thank
Hello, Dr. Favaloro, thank you for your comment. Upon further checking, Our UAB folks indeed do follow the same protocol as you, infrequently using applicator sticks to examine any specimen, including spun specimens, whose results are suspicious.
Hi George, the question posed
Hi George, the question posed is not entirely clear. We would certainly not encourage routine checks for clots using applicator sticks ahead of testing, but we do still use the method for assessing occasional samples where events may need some clarity around whether a clot may be present. The classical examples are ‘flow obstructions’ identified by the PFA-100/-200, or ‘indefinitely’ prolonged clot times in routine assays. It is helpful to investigate these and potentially identify clotting to help justify recollections, if only to help educate the blood collector to improve their procedural practice. Yes, one can argue it doesn’t change the result, and exposes staff to blood and potential viral exposure, but it helps explain to the doctors why we can’t obtain or issue a particular test result, and blood exposure is never totally avoidable in our field.