Difference Between INR and aPPT (With Table)

Our health is an important factor for a good and long life. The ways to treat problems and diseases have been changing for many years. Allopathic and homoeopathic/ ayurvedic are different modes and types of treatments. 

Allopath is a huge sector in today’s world. They conduct various tests to deduct or cure the problems. If these tests are not performed, the exact problem of the patient won’t be understood, and there will be no cure. INR and aPPT are two such tests that are conducted on blood samples to test whether or not your blood clots normally.

INR vs aPPT

The difference between INR and an aPPT test is that the INR blood tests assess the extrinsic pathway to deduct the nature of blood clots, whereas the aPPT blood test assesses the functions of the intrinsic pathway of coagulation to deduct the nature of blood clots.

An INR or the PT/INR test is conducted to check how long (in seconds) it takes for a clot to form in the blood sample. INR is the abbreviation of international normalized ratio. It is based on the calculation of the PT test (prothrombin time) results. It is used to assess the extrinsic (tissue factor) pathway of coagulation. It is also used to monitor people who are treated with warfarin.

An aPPT test is used to assess the intrinsic pathway of coagulation. It measures the time taken (in seconds) to form a clot after the reagents are added to the blood sample. aPPT is the abbreviation for activated partial thromboplastin time. A normal appt value is 30 to 40 seconds. It is used to monitor people who are treated with heparin.

Comparison Table Between INR and aPPT

 Parameters of Comparison INR aPPT
 Definition An international normalized ratio (INR) test is conducted to check if the patient’s blood levels/nature is normal. It checks in how many seconds does the blood clot. Activated partial thromboplastin time (aPPT) is a test to check the levels/nature of blood clots; it checks the time( in seconds) it takes to form a clot.
 Pathway The INR test assesses the extrinsic pathway when then meets the common pathway. The aPPT test assesses the intrinsic pathway, which then goes to the common pathway.
 Clotting Factor The INR test assesses the following clotting factors – VII, I, II, V, X. These factors are related to the extrinsic and common pathway. This test assesses the following clotting factors – XII, XI, IX, VIII, I, II, V, X. These are related to an intrinsic and common pathway.
 Normal Reference Range The normal range of the INR test is 10-20 seconds. The normal range of the aPPT test is 30-40 seconds.
 Anticoagulant  The INR test is done on the patients who are on warfarin. When this anticoagulant is taken, the INR level is needed to be 2-3 when checked. The aPPT test is done on those who are on heparin, and when this anticoagulant is taken, the aPPT level is needed to be 1.5 to 2.5 times the normal range.

What is INR?

The international normalized ratio (INR) is calculated based on the results of prothrombin time (PT), which helps evaluate a person’s ability to form clots. Hence it can also be called PT/INR test. It is used to monitor individuals who are being treated with warfarin (anticoagulant) which is a medication to thin the blood.

The liver makes a protein known as prothrombin. Prothrombin times help to measure the amount of time (in seconds) it takes for a clot to form in the blood sample once the reagents are added. If you bleed a lot after an injury, then that means your clotting factor levels are too low, and if there are serious high-level clots as soon as you get hurt, then that means your clotting levels are very high, which can be dangerous for the arteries and veins.

This test is used for checking problems in the liver, functions/nature of the clot before conducting any surgery, unusual bleeding, the occurrence of abnormal clots, etc. if you have any symptoms like heavy bleeding, swelling in the leg, heaving bleeding in the nose, trouble breathing, etc. then you should get a test done.

You must delay the dose of warfarin (if you have it regularly) for the test. The blood sample is taken from your fingertip or vein.

What is aPPT?

Activated partial thromboplastin time (aPPT) test to check the levels/nature of blood clots, assesses the intrinsic pathway of coagulation and also checks the heparin anticoagulant therapy. The sample of the blood is taken from the veins in the arm. When you hurt yourself, and it starts to bleed, the platelets clump at the site of the injury. The coagulation cascade activates the coagulation factors to clot or stop the blood. But when this does not happen, you need to get a checkup done.

The aPPT test measures time in seconds that it takes for clotting to occur when the reagents are added into the plasma. The test needs to be done when a woman has had recurrent miscarriages, chronic conditions like liver diseases, unexplained bleeding, or bruises. The normal reference range for the aPPT test should be 30 to 40 seconds. The clotting factor that the appt test looks into are – factor XII, XI, IX, VIII, I, II, V, X. If the patient is on a dose of heparin, the aPPT is needed to be 1.5 – 2.5 times the normal range.

Main Differences Between INR and aPPT

  1. INR blood test assesses the extrinsic pathway, whereas aPPT blood tests assess the functions of the intrinsic pathway. They both then meet the common pathways.
  2. Keeping extrinsic pathway and common pathway in mind, the PT/INR test assesses the following clotting factors – VII, I, II, V, X. whereas the aPPT that asses through intrinsic and common pathway look into – XII, XI, IX, VIII, I, II, V, X.
  3. The normal reference range of the PT/INR test is 10-12 seconds, whereas the normal range for the aPPT test is 30-30 seconds.
  4. The INR test is used to monitor an individual’s warfarin levels, whereas the aPPT test monitors the heparin levels.
  5. When the patient is taking warfarin, they are needed to have an INR level of 2-3, whereas if the patient is on heparin, the aPPT is needed to be 1.5-2.5 times the normal range.

Conclusion

The INR and aPPT are both used to test the same thing but still have a few differences, which are important to be noted. These tests though small, are very important and make a huge difference when it comes to a patient’s health. There is a risk if the levels are too high or too low, and hence tests need to conduct.

The health industry/ technology has changed a lot over the years. Earlier, there was less equipment or treatments, but day by day, the technology is developing. We will witness many more advancements and changes in the future.

References

  1. https://www.sciencedirect.com/science/article/pii/S0049384804003305
  2. https://www.researchgate.net/profile/Jack_Hirsh/publication/6716797_Monitoring_unfractionated_heparin_with_the_aPTT_Time_for_a_fresh_look/links/0c96051929a8456bc8000000/Monitoring-unfractionated-heparin-with-the-aPTT-Time-for-a-fresh-look.pdf
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