PT, INR, and APTT Test: Introduction, Test Result, Unit, Normal Range, Test Method, Clinical Significance, and Keynotes

Introduction

The PT, INR, and APTT tests are the common coagulation profile test. The prothrombin time (PT) test measures how rapidly blood clots. The international normalized ratio (INR) calculation assists to ensure that prothrombin time (PT) test results are standardized and accurate. The activated partial thromboplastin time (APTT) is mainly used to measure the amount of time it takes for a blood clot to form and thus it also helps to monitor a patient’s response to anticoagulant therapies.

Test Result, Unit, Normal Range, and Test Methods of Prothrombin Time, INR, and APTT Test

Clinical Significance of PT, INR, and APTT Test

The uses of PT/INR and APTT tests are as follows-

1. To check the effect of warfarin is a blood-thinning medicine used to treat and prevent dangerous blood clots.
2. Find out the reason for abnormal blood clots
3. To know the reason for unusual bleeding
4. Check clotting function prior to surgery
5. Find out liver problems

Keynotes

• Coumadin is a common brand name for warfarin.
• A PT/INR test is often tested along with a partial thromboplastin time (PTT) test which also checks for clotting problems.
• The common symptoms of a bleeding disorder are unexplained heavy bleeding, bruising easily, sudden heavy nose bleeds, and unusually heavy menstrual period.
• The common symptoms of a clotting disorder are leg pain or tenderness, leg swelling, trouble breathing, redness or red streaks on the legs, chest pain, cough, and rapid heartbeat.
• The doctor needs a PT/INR test report before the surgery that helps make sure blood is clotting normally, so the patient won’t lose too much blood during the procedure.
• A blood coagulometer is an analyzer/ instrument used to assay the coagulation efficiency of blood so as to diagnose and assess bleeding disorders like hemophilia or to monitor patients who are taking anticoagulant medicines e.g. aspirin, heparin, or warfarin.
• Blood is drawn in a vial having tri-sodium citrate anticoagulant that is the choice of anticoagulation of coagulation profile tests.
• PT/INR and APTT results together are used in diagnosing various hematologic disorders.

Bibliography

• https://pubmed.ncbi.nlm.nih.gov/3706933/
• https://www.ncbi.nlm.nih.gov/books/NBK544269/
• https://www.mayoclinic.org/tests-procedures/prothrombin-time/about/pac-20384661
• https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=aptt