Measured in seconds to clot formation, normal PTT can vary based on laboratory or institution; however, normal PTT is
between 25 to 35
. PTT ranges are used to classify heparin dosing schemes as low or high intensity and to ensure effective dosing.
What is the normal value range for an aPTT?
| TEST NORMAL RANGES* | PT 10-12 seconds | PTT 30-45 seconds | INR 1:2 ratio |
|---|
What is high PTT?
A prolonged PTT means that
clotting is taking longer to occur than normal
and may be due to a variety of causes.
What is the normal range for PTT and INR?
Normal Results
Most of the time, results are given as what is called INR (international normalized ratio). If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is:
11 to 13.5 seconds
.
INR of 0.8 to 1.1
.
What does it mean when PTT is low?
A longer-than-normal PTT or APTT can mean a lack of
or low level of one of the blood clotting factors or another substance needed to clot blood
. This can be caused by bleeding disorders, such as hemophilia or von Willebrand’s disease.
What happens if aPTT is high?
A prolonged aPTT usually means that
clotting is taking longer to occur than expected
(but is associated with increased risk of blood clots if due to a lupus anticoagulant) and may be caused by a variety of factors (see the list below).
What does PTT indicate?
Partial thromboplastin time
(PTT) is a blood test that looks at how long it takes for blood to clot. It can help tell if you have a bleeding problem or if your blood does not clot properly. A related blood test is prothrombin time (PT) .
What is difference between PT and PTT?
Two laboratory tests are used commonly to evaluate coagulation disorders: Prothrombin Time (PT) which measures the integrity of the
extrinsic
system as well as factors common to both systems and Partial Thromboplastin Time (PTT), which measures the integrity of the intrinsic system and the common components.
What is the difference between PT and aPTT test?
Partial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) are used to test for the same functions; however, in aPTT, an activator is added that speeds up the clotting time and results in a
narrower reference
range.
Is PT the same as INR?
A prothrombin time (PT) is a test used to help detect and diagnose a bleeding disorder or excessive clotting disorder; the
international normalized ratio
(INR) is calculated from a PT result and is used to monitor how well the blood-thinning medication (anticoagulant) warfarin (Coumadin®) is working to prevent blood …
Is INR 0.9 Bad?
The INR is intended to standardize reporting of the prothrombin time. For patients NOT on anticoagulants,
the reference range for the INR is 0.9-
1.2. The recommended therapeutic range for warfarin is an INR of 2.0-3.0. (Exception: The recommended range for many mechanical valves is INR 2.5-3.5.)
Is 1.9 INR good?
An INR of 1.9 or less is associated with
an almost doubling of risk for thrombosis
compared to an INR within the therapeutic range. So, a dose increase is likely warranted.
What does an INR of 1.5 mean?
A result of 1.0, up to 1.5,
is therefore normal
. A low INR result means your blood is ‘not thin enough’ or coagulates too easily and puts you at risk of developing a blood clot. A high INR result means your blood coagulates too slowly and you risk bleeding.
What happens if aPTT is low?
If your number is lower than normal, which doesn’t happen often, you may have
a higher chance of getting blood clots
and, for women, having several miscarriages. You’ll likely get more tests to find out what’s going on.
What causes low Pt levels?
Clotting too slowly
Blood-thinning medications. Liver problems. Inadequate levels of proteins that cause blood to clot.
Vitamin K deficiency
.
What drugs affect PTT?
Drugs that may prolong the test values, including
antihistamines, ascorbic acid, chlorpromazine, heparin, and salicylates
. Incorrect blood-to-citrate ratio. Hematocrit that is highly increased or decreased. Blood samples drawn from heparin lock or a heparinized catheter.
