use of fingerstick vs Venipuncture to test INRs

  1. 0
    I have been looking for a definite answer for this one but having no luck! I would like to know how long do we wait to do a fingerstick INR via portable unit to test a patient's level after the last dose of an injectable Blood thinner(lovenox, arixtra,etc)? We do not use the portable units while patients' are on injectables but wonders how long we should wait to use the portable units and get ACCURATe results.
    Thanks!

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  2. 6 Comments...

  3. 0
    I read your other thread on this too, but I'm still not quite in the clear. Are you talking about concurrent coumadin regimen or resuming coumadin after injectables?
  4. 0
    Yeah, i am new to allnurses & i accidentally posted the thread in this section!
    Anyway, i am referring to both--concurrent coumadin& injectable therapy and resuming coumadin after injectables.
    So far i have an answer of waiting til halflife of lovenox which is 4.5hrs.
    Any other answers would be appreciated!
  5. 0
    I'm not really sure what you're asking either. I'm not an expert in this but as far as I know INRs can be done by fingerstick or venous sample and are done to monitor warfarin therapy not injectables. A different test is used to monitor the effectiveness of enoxaparin and as far as I know there's no way to do this with a portable machine.

    When resuming warfarin after injectables, patients often stay on injectables until the INR is in the target range so there's no need to wait any particular length of time. You wouldn't check the INR if the patient isn't on warfarin. Does that help at all?
  6. 0
    We draw serum PT/INR levels for patients in injectables per MD orders. But when they are done with the injectables and will solely be on the Coumadin, that's what we are trying to come up with a protocol for our agency as to when our nurses should do a venipuncture or use a portable when our patients have finished the last dose of their injectable(either concurrent with PO Coumadin or with just the injectables alone) so MDs know whether to extend the injectables or not.(homehealth setting ,btw)

    We have been waiting 5-7hrs after the last dose of the injectable before we draw their PT/INR level via portable unit. But I was just wondering if there were any other protocols/parameters out there that I didn't know about.
    Glad to know we've been doing it right waiting 5-7hrs(given that halflife is 4.5hrs for lovenox)!
    Thanks again for the reply!
  7. 0
    Quote from HHRN22
    We draw serum PT/INR levels for patients in injectables per MD orders. But when they are done with the injectables and will solely be on the Coumadin, that's what we are trying to come up with a protocol for our agency as to when our nurses should do a venipuncture or use a portable when our patients have finished the last dose of their injectable(either concurrent with PO Coumadin or with just the injectables alone) so MDs know whether to extend the injectables or not.(homehealth setting ,btw)

    We have been waiting 5-7hrs after the last dose of the injectable before we draw their PT/INR level via portable unit. But I was just wondering if there were any other protocols/parameters out there that I didn't know about.
    Glad to know we've been doing it right waiting 5-7hrs(given that halflife is 4.5hrs for lovenox)!
    Thanks again for the reply!
    Okay but I think what I'm saying is that the INR is measured to determine the effectiveness of warfarin therapy, not the effectiveness of Lovenox therapy and it doesn't matter whether it's done by venous sample sent to the lab or by fingerstick at home, it's still only measuring the INR.

    If the patient has been discharged on both warfarin and Lovenox, they usually stay on Lovenox until their INR is in the target range so you'd need to check the INR dependent of the timing of the last dose of warfarin, not the last dose of Lovenox.

    If they've just finished their Lovenox and are on warfarin only, I really don't think you need to wait any particular time after the last dose of Lovenox. The warfarin dose will be adjusted according to the INR and when the last dose of warfarin was taken.

    There's lots of good information out there on warfarin therapy, your local pathology company would probably be able to help you. Maybe the doctor wants samples sent to the lab during this transition period because the fingerstick INR may not be as accurate?

    I have a feeling I'm still not answering your question.
  8. 0
    You did answer my question! I appreciate it! I am so glad i signed up here to have other people's input on stuff like this! Thank you!


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