PTT & APTT - Differences?

Published

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 that PTT is also called APTT, however, this really confuses me since their normal values are very different.

What would you use one for, but not the other?

Thanks! :)

Up Vote Up Vote ×
Specializes in Utilization Management.

The APTT and the PTT are the same. The Activated Partial Thromboplastin Time and the Partial Thromboplastin Time are the same--the second one's just abbreviated.

You'll usually use this test for a patient who is on Heparin. The heparin protocol will call for parameters on the rate of heparin to run based on the APTT. The order will read something like "If APTT 25-36, increase to 10 units/hour and repeat APTT in 6 hours."

Now, the PT--or Prothrombin Time--is a different type of measure of coagulation that's usually used to determine how much Coumadin a person has in their system. And more often, we use the INR as the parameter, which is the second half of that test. The lab order will read "PT/INR daily" or something like that.

You'll usually see an order for a patient like "Coumadin 3 mg po qd. Hold if INR >2.8."

I could go on and on....let me know if you have more questions about anticoagulation. I'll be happy to share info.

Up Vote Up Vote ×

Thank you for taking the time to reply!!! :)

Our textbook shows a chart with various diagnostic tests. All three (PT, PTT, and APTT) are shown, as well as their lab values. For the tests PTT and APTT, it does say they are the same, however it shows different normal lab values for APTT and PTT (not to be confused with PT).

I guess I'm trying to figure out that since PTT and APTT are the same test, why are the normal lab values different, and what would any (if any) differences there are?????

Oh the joys of being a nursing student!!!! :chuckle

Thanks again!!!!!!

Up Vote Up Vote ×
Specializes in Utilization Management.
Quote
For the tests PTT and APTT, it does say they are the same, however it shows different normal lab values for APTT and PTT (not to be confused with PT).

Is it possible that the lab values are different because the norms are different for people who are under anticoagulation therapy?

In other words, norm will be 25-35 seconds, but if Patient is being anticoagulated (let's say Patient has a heart valve replacement, for instance)--then the normal value for that patient would be 1.5-2.5 times higher than controls.

That's the only way I could see two answers as being correct.

Now you have me scratching my head over this too. Suggestion: a lot of these newer texts have websites you can go to. Check either the front or back cover of the book? They might be helpful and answer that question better than I can, since they can see what you're looking at and I can't.

Good luck! And let me know what happens, 'cause now I'm curious, ok?

Up Vote Up Vote ×
Specializes in Emergency, Outpatient.

The activated partial thromboplastin time (aPTT) is a common screening test done to evaluate function of the intrinsic clotting system.

It has largely replaced the older PTT, which was unable to incorporate variables in surface/contact time.

The aPTT now measures the clotting time of plasma, from the activation of factor XII by a reagent (a negatively charged activator such as silica and a phospholipid) through the formation of a fibrin clot.

If a patient's aPTT is abnormal, additional tests will be done to determine the exact cause of the coagulation problem.

Hope that helps taken from http://www.rnceus.com/coag/coagptt.html

Adria

Up Vote Up Vote ×
Specializes in Gerontological, cardiac, med-surg, peds.

Wow! Thanks for sharing!

Now, let's add a little more fun to this thread:

Which value, PT or PTT, does heparin influence?

Which one does coumadin?

Stumped?

You can find the right answer by counting to 10:

- - - - - - - - - - = 10

H E P A R I N (7 letters) + 3 (PTT) = 10

C O U M A D I N (8 letters) + 2 (PT) = 10

Here's another one:

What is the antidote for heparin overdose?

Protamine sulfate (just remember P M S)

What is the antidote for too much Coumadin?

Vitamin K (just remember the hard "C" at the beginning of coumadin!)

Well, that's enough fun for tonight!

Up Vote Up Vote ×
Specializes in MICU.

What is the antidote for heparin overdose? Ffp

What is the antidote for too much coumadin?Ffp

Sorry, maybe that was not so funny. We had a patient earlier this week with a pt of 92 (yes, ninety two) and inr was insane (like 61). How do little patients get this confused?

Are the pharmaceutical companies starting to market coumedin in prefilled pez dispensors?

Up Vote Up Vote ×

Are the pharmaceutical companies starting to market coumedin in prefilled PEZ dispensors?

Must be....I work in the Blood Bank, and it seems as if all we do anymore is thaw mass quantities of FFP. Docs yelling for it...and it takes 30 min to thaw....remember, it's FROZEN.....

Up Vote Up Vote ×
VickyRN said:
Wow! Thanks for sharing!

Now, let's add a little more fun to this thread:

Which value, PT or PTT, does heparin influence?

Which one does coumadin?

Stumped?

You can find the right answer by counting to 10:

- - - - - - - - - - = 10

H E P A R I N (7 letters) + 3 (PTT) = 10

C O U M A D I N (8 letters) + 2 (PT) = 10

Here's another one:

What is the antidote for heparin overdose?

Protamine sulfate (just remember P M S)

What is the antidote for too much Coumadin?

Vitamin K (just remember the hard "C" at the beginning of coumadin!)

Well, that's enough fun for tonight!

VERY NICE.

Up Vote Up Vote ×

I have issues with these stuffs as well. one other mnemonic i found is " PET PITT BULL" what that means is that PT is for the extrinsic pathway and PTT is for the intrinsic pathway. get?:thankya:

Up Vote Up Vote ×
Specializes in My first yr. as a LVN!.

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

Up Vote Up Vote ×

is there a test to measure the effects of lovenox? just curious

Up Vote Up Vote ×
+ Join the Discussion