PTT & APTT - Differences? - page 2

by kate930 157,577 Views | 21 Comments

Other than the normal values, what is the difference between the APTT and the PTT? Since the lab values are difference, I would "assume" that there has to be some different between the two, other than the name. All I find is... Read More


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    I know this is an old thread but was going over this before my NCLEX which is tomorrow, so thought Id pipe in ... PT and INR measures for Coumadin therapy.. to check the ratio of Coumadin in the blood to prevent excessive bleeding those who are on anticoag. meds should be 2-3 while those who are at higher risk the INR should be 2.5-3.5 ... the higher the number the longer it takes for the blood to clot...meds. alter readings as well as foods w Vit K. The aPTT is for excessive bleeding tendancies that is done for pre surg. or unexplained miscarriages, bruising or blood clots (DVT)--pt. reveiving Heparin--... though they are somewhat simlar.. they are different ... apTT bleeding should be a value of 1.5-2.5 ... hope this helps .. and I hope I explained right ... :icon_roll
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    is there a test to measure the effects of lovenox? just curious
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    excellent source for info.



    http://stroke.about.com/od/caregiver...d_thinners.htm


    lovenox


    lovenox, also called enoxaparin, is a form of heparin called fractionated heparin. lovenox does not require monitoring of its blood levels and it can be injected intramuscularly. people with chronic kidney disease should not use lovenox as poor kidney function makes lovenox accumulate in the blood. the side effects of lovenox include skin irritation at the site of injection and nausea.
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    let me give you a scenario to see if i've got it. If the control on a ptt test is 35 and the result is 50 since it could be 1.5-2.5 times the control when on heparin would that mean that the person would receive more heparin? thanks, kinda confused.
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    Cool, that works for me...but...how are the antidotes administered normally? By which route?
    Thanks!
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    Protamine, the heparin antagonist, is given IV.
    Vitamin K (phytonadione), the warfarin antagonist, is given orally, subcutaneously or IM.
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    Thought I'd add a different look at PTT vs aPTT as I learn it (even though this was answered back in 2004)

    PTT is the old test that adds Partial Throboplastin to blood in order to mimic the contribution that platelets provide in the body (specifically, plasma membrane phospholipids). Once added, the test measures the time it takes to clot. The problem with PTT was that the PTT time included the variable timeframe where the clotting factors needed to come into contact with each other and become 'activated' and begin clot formation.

    So PTT was modified to aPTT to remove this variable time-to-activation by adding factors to completely activate your blood sample before you start timing clot formation. You strip away the variable time to activation, which is not really what the test is trying to measure. We want to know how long it takes to form a clot from the time the "clot switch" has been flipped on.

    This is the major reason why PTT normals [roughly 60-70 sec] are longer than aPTT normals [roughly 25-40ish] but in the whole scheme of things, both are testing for abnormal clotting times via the intrinsic pathway (either too short or too long, usually the latter). Hope that helps make sense of it all.
    Last edit by rbrychckn on Oct 30, '08 : Reason: Edit for grammar
    Hygiene Queen, stellina615, celclt, and 1 other like this.
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    omg I love you guys :-)
  9. 1
    Quote from heartjulz
    excellent source for info.



    http://stroke.about.com/od/caregiver...d_thinners.htm


    lovenox


    lovenox, also called enoxaparin, is a form of heparin called fractionated heparin. lovenox does not require monitoring of its blood levels and it can be injected intramuscularly. people with chronic kidney disease should not use lovenox as poor kidney function makes lovenox accumulate in the blood. the side effects of lovenox include skin irritation at the site of injection and nausea.
    i don't wanna nitpick, but are you sure about that? lovenox is usually given subq and never im because muscle is so much better perfused than the sq and more likely to result in a hematoma.

    http://www.aahcp.org/dvt/faqs.htm
    cardiacRN2006 likes this.
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    I've never given lovenox IM, nor have I ever seen that...

    Just look at the size of the needle, it's clearly meant for SubQ.


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