Interpreting these PT/INR, APTT, and D-Dimer results

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ok so i am working on my care plan and i'm trying to figure out how to rationalize why a pt/inr, aptt, and d-dimer were drawn on my patient and the signifance of the normal values. he was not on anticoagluant therapy at home and does get 5000 u heparin sq qd in hous for dvt prophylaxis....but again these were drawn on admission. he came in in resp distress secondary to an urti x 2 weeks and was diagnosed with pneumonia. his d-dimer was elevated and i know that raised suspicion for pe but it was ruled out on ct. but anyone know why the pt inr and aptt would have been ordered????

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Specializes in med/surg, telemetry, IV therapy, mgmt.

the d-dimer is the give away. a pe is not the only place in the body where the patient can develop a blood clot. what was he on long-term anticoagulation therapy for in the first place? a pe in the past? has he had a history of a phlebitis or embolism anywhere else? is he at risk for a dvt? what's the blood pressure like? was there anything in the physician's history and physical, progress notes or the nursing admission assessment to indicate why the careful watch on his anticoagulation status. the fact that d-dimers are being drawn is an indication that the physician is worried that there is blood clot breakdown going on somewhere in this person's body. sounds like there is an element of the patient's history missing from your assessment here.

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Specializes in med/surg, telemetry, IV therapy, mgmt.

Want to add that the D-Dimer could also be done because they are monitoring or looking for another underlying disease process such as DIC syndrome which is often connected with an acute infection.

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this patient doesn't have a history of clots or phlebitis and isn't on long term anticoag therapy...that's where my confusion lies with these labs being drawn on admission. his hx includes htn controlled by lifestyle modification, type ii dm, copd newly diagnosed, & hyperlipidemia. he came in in resp distress and chest pain (which i can see as a reason maybe to do the labs but turned out to be related to the pneumonia). his bp trends in the 130's over 60s and is not on any bp meds. he is at risk for dvt's now that he is on br in the hospital but was not previous to admission. the only thing the md's notes said about a concern for clots was to do a ct scan to rule out pe after the d-dimer was elevated.

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Specializes in ACNP-BC, Adult Critical Care, Cardiology.

Another reason I can think of as far as PT/INR and aPTT being ordered was to establish a baseline coagulation study just in case the work-up was positive for a PE or any other clot. The baseline aPTT is needed for therapeutic drug monitoring of unfractionated heparin drip dosing which is one of the treatment modalities for a PE.

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I am not surprised that the CT scan was neg for PE. Most of the lab is to rule out. the physician has to be sure that the resp distress is in fact from the pneumonia and not something else going on too. Since the patient is negative for PE with elevated pt/inr and ptt with a positive D-dimer there is a very good chance that the patient is in DIC brought on from infection-URI x 2 weeks. The next step I would venture to guess would be to order fibrinogen levels and fibrinogen split products levels. If these are abnormal the patient may require fresh frozen plasma or cryoprecipitate to correct the insueing bleeding disorder.

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the physician has to be sure that the resp distress is in fact from the pneumonia and not something else going on too. since the patient is negative for pe with elevated pt/inr and ptt with a positive d-dimer there is a very good chance that the patient is in dic brought on from infection-uri x 2 weeks.

that's what i was thinking.... but only the d-dimer was elevated; the pt/inr and aptt were normal. i thought aptt pt/inr were only drawn for pt's on anticoag therapy...that's what confused me esp since he has no hx of clots or anticoag therapy. you learn something new everyday...an i could use all the knowledge i can get with the nclex creeping up closer anf closer now....

thanks everyone for your help!!!! i really appreciate it!

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Specializes in ER, ICU, Infusion, peds, informatics.

you know, sometimes coags are ordered just because....without any really good reason, esp in the er during the initial workup.

while i admire you for trying to figure out the rationale, i hate to see you expending so much energy on the topic.

when a patient comes in experiencing resp distress, things are often set into motion. typical scenerio: often, i will start a line and draw blood right off the bat, before anything else (other than vs) to get things going. while i'm ordering our labs on the order sheet, i will ask "are you taking any blood thinners?" since our protocol is to check coags if they are on coumadin (or maybe even lovenox at home). the patient says "yes," so a ptt/pt/inr all get ordered. then, when going through the med list with the patient/family, we discover that the "blood thinner" is actually asa. many patients think of this as a blood thinner, which it is, it just isn't one that requires pt/ptt monitoring. we don't cancel the lab, even though it really isn't necessary.

or, could be that the patient had some bruising, was c/o "bleeding easy" or just for whatever reason the doc felt the coags should be checked. maybe a gut feeling. like someone else said, maybe they wanted a baseline in case the ct was positive.

there could be several reasons. maybe the patient was in rm 10, and the coags should have been ordered on rm 11 (that is how one of my male patients managed to get a pregnancy test once.....thankfully, it was negative).

my point is, there could be many reasons why coags were ordered in the initial er workup. some of them really arn't "good" reasons. don't waste too much energy trying to figure it out.:wink2:

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Specializes in med/surg, telemetry, IV therapy, mgmt.

i understand why you want to know the answer to this. however, just as a nursing intervention we will often order the monitoring of a patient's signs and symptoms, doctors will do the same. it is not our job to rationalize or be utilization monitors to the doctors. docs do have the authority to order lab tests as they desire without explaining why to us nurses. just because a doctor orders a lab test does not mean that you have to justify those particular pieces of data assessment for your care planning, particularly if they are within normal limits. remember that in addressing patient problems and determining nursing diagnoses you are only concerned with the abnormal assessment items. at this point, probably the only way you are going to find out why these tests have been re-ordered is to get another look at the chart or call the doctor and ask him. it's not something that i would lose sleep over.

it had also crossed my mind that there might have been a screw up and these lab tests were erroneously ordered without the doctor realizing that they had already been drawn. i've seen that happen a lot, particularly when a patient is seen in the er first by an er doctor. is that possible?

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thanks again for all your help. i understand what you're saying and i wholeheartedly agree!! trust me, i didn't want to spend my sat night trying to figure that and many other things out. i'm working on my big care plan for my icu patient and we are told that we have to explain why each abnormal is abnormal and even for normals...why was it ordered....what were they looking for.....why is that important??? that's why i was so dedicated to finding the answer!!!

thanks again!!!!

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In our ER, PT, PTT, INR are part of the cardiac panel (lab tests ordered on all chest pains, SOB's, etc). We draw them on all pts presenting with these symptoms, they are not individually ordered.

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