Coagulation Profile (PT/INR & aPTT)
Understanding Coagulation Profile (PT/INR & aPTT)
What is Coagulation Profile (PT/INR & aPTT)?
A Coagulation Profile (PT/INR & aPTT), incorporating prothrombin time international normalized ratio (PT/INR) and activated Partial Thromboplastin Time (aPTT) test, is a comprehensive blood test that assesses the body's ability to form blood clots. This profile helps diagnose bleeding disorders, such as hemophilia, and monitor the effects of anticoagulant medications.
Clotting or coagulation factors are the proteins found in the blood that help stop bleeding when there is a wound or cut. A Coagulation Profile (PT/INR & aPTT) is used to assess the clotting function of the blood and determine if there is a problem with any of your clotting factors. Your doctor may suggest this test if you have symptoms of bleeding or clotting disorders, such as unexplained heavy bleeding, easy bruising, unusual heavy nose bleeds, leg swelling, redness on the legs, or chest pain. This test can also help check for clotting function before a scheduled surgery.
A Coagulation Profile (PT/INR & aPTT), including PT/INR and aPTT tests, is used to assess the risk of bleeding or clotting disorders, such as hemophilia, deep vein thrombosis, vitamin K deficiency, monitor anticoagulant therapy, and evaluate liver function. A PT/INR test helps measure how long it takes for blood to clot. The International Normalized Ratio (INR) is a standardized method used to interpret test results consistently. This test is used primarily to monitor the effectiveness of anticoagulant medications, such as warfarin, and assess liver function. The aPTT test especially helps evaluate the effectiveness of anticoagulant medications, such as heparin.
Usually, overnight fasting (8-12 hours) is preferred before a Coagulation Profile (PT/INR & aPTT), and a duly filled coagulation requisition form is mandatory for sample collection. If you take anticoagulant medication, giving the testing sample before the daily dose is taken is advised. Also, inform the doctor if you are taking medications such as blood thinners, as they may interfere with test results, and your doctor may adjust your dose or stop them temporarily before the test.
Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Talk to your doctor about your specific test results. Narrate your complete medical and family history to help the doctor correlate your clinical and laboratory findings. The test results will help them prevent, manage, and treat coagulation-related health issues.
What is Coagulation Profile (PT/INR & aPTT) used for?
A Coagulation Profile (PT/INR & aPTT) test is done:
- To detect and diagnose bleeding disorders or clotting disorders.
- In case of excessive unexplained bleeding.
- In case of easy bruising.
- Before planning a surgical procedure.
- In conditions that may affect clotting factors in your blood, such as liver disease, lack of vitamin K, blood transfusion, cancer, and autoimmune disorders.
- To monitor the efficacy of the treatment with anticoagulant medications, such as warfarin.
What does Coagulation Profile (PT/INR & aPTT) measure?
Contains 2 testsA Coagulation Profile (PT/INR & aPTT) includes blood tests that provide information about the blood's clotting ability. This profile measures prothrombin time international normalized ratio (PT/INR) and activated partial thromboplastin time (aPTT).
The Prothrombin Time (PT) and aPTT tests measure how long the blood takes to clot. Precisely, they assess the factors in the blood that help initiate the clotting process. The INR is a standardized interpretation of the PT results. It is calculated to ensure consistency in interpreting PT values across different laboratories and testing methods. The INR is essential when monitoring patients on anticoagulant medications like warfarin. The INR helps adjust medication dosages to maintain blood clotting within a therapeutic range. The aPTT test is significant when monitoring patients on anticoagulant medications, such as heparin.
PT INR (Prothrombin Time)
The PT INR (Prothrombin Time) test measures the Prothrombin Time (PT) and reports it as the International Normalized Ratio (INR). The PT measures how long it takes for blood to clot. Specifically, it assesses the factors in the blood that help initiate the clotting process. The INR is a standardized interpretation of the PT results. It is calculated to ensure consistency in interpreting PT values across different laboratories and testing methods. It is particularly important when monitoring patients on anticoagulant medications, such as warfarin. The INR helps adjust medication dosages to maintain blood clotting within a therapeutic range.
Know more about PT INR (Prothrombin Time)
Activated Partial Thromboplastin Time
An Activated Partial Thromboplastin Time test measures the time taken by the blood to form a clot. In other words, it is a screening test that helps evaluate a person’s ability to form blood clots. The test analyzes the amount and the function of specific proteins in the blood called coagulation or clotting factors, which are an essential part of blood clot formation.
Blood clotting or coagulation occurs through a series of cascade reactions due to the activation of clotting factors. There are a total of thirteen clotting factors within our bodies that aid in clot formation, and for healthy clot formation, all clotting factors need to be in the right balance. Any imbalance of these factors can lead to a blood clotting disorder.
Know more about Activated Partial Thromboplastin Time
Interpreting Coagulation Profile (PT/INR & aPTT) results
Interpretations
Prothrombin time: 11 s - 15 s
Activated partial thromboplastin time: 25 s - 35 s
The reference range may vary from lab to lab*
|
Results of PT |
Results of PTT |
This can be seen in the following conditions |
|
Prolonged |
Normal |
Diseases of the liver, Vitamin K deficiency, Defective factor VII, Chronic disseminated intravascular coagulation |
|
Normal |
Prolonged |
Hemophilia A or B, Factor XI deficiency, Von Willebrand disease, Factor XII deficiency, Presence of lupus anticoagulant |
|
Prolonged |
Prolonged |
Defective factor I, II, V or X, Severe liver disease, Acute disseminated intravascular coagulation |
Answers to Patient Concerns & Frequently Asked Questions (FAQs) about Coagulation Profile (PT/INR & aPTT)
Frequently Asked Questions about Coagulation Profile (PT/INR & aPTT)
Q. What is a Coagulation Profile (PT/INR & aPTT)?
Q. What are the risks associated with a Coagulation Profile (PT/INR & aPTT)?
Q. When should I take a Coagulation Profile (PT/INR & aPTT)?
Q. What conditions can affect blood clotting to cause bleeding disorders?
Q. What other tests can be advised by the doctor in case of abnormal results of a Coagulation Profile (PT/INR & aPTT)?
Q. What should I do if my bleeding does not stop?
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References
- Condrey JA, Flietstra T, Nestor KM, Schlosser EL, Coleman-McCray JD, Genzer SC, Welch SR, Spengler JR. Prothrombin Time, Activated Partial Thromboplastin Time, and Fibrinogen Reference Intervals for Inbred Strain 13/N Guinea Pigs (Cavia porcellus) and Validation of Low Volume Sample Analysis. Microorganisms. 2020 Jul 27;8(8):1127. [Accessed 21 Sept. 2023]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7463423/#:~:text=PT%20is%20the%20time%20in,along%20with%20calcium%20and%20phospholipids.
- Yuan S, Ferrell C, Chandler WL. Comparing the prothrombin time INR versus the APTT to evaluate the coagulopathy of acute trauma. Thromb Res. 2007;120(1):29-37. [Accessed 21 Sept. 2023]. Available from: https://pubmed.ncbi.nlm.nih.gov/16887171/
- Doherty TM, Kelley A. Bleeding Disorders [Internet]. Treasure Island, Florida: StatPearls Publishing; 2023 Jan. [Accessed 21 Sept. 2023]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK541050/
- Barbosa ACN, Montalvão SAL, Barbosa KGN, Colella MP, Annichino-Bizzacchi JM, Ozelo MC, De Paula EV. Prolonged APTT of unknown etiology: A systematic evaluation of causes and laboratory resource use in an outpatient hemostasis academic unit. Res Pract Thromb Haemost. 2019 Sep 8;3(4):749-757. [Accessed 21 Sept. 2023]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6782020/
- Kershaw G. Performance of Activated Partial Thromboplastin Time (APTT): Determining Reagent Sensitivity to Factor Deficiencies, Heparin, and Lupus Anticoagulants. Methods Mol Biol. 2017;1646:75-83. [Accessed 21 Sep. 2023]. Available from: https://pubmed.ncbi.nlm.nih.gov/28804819/
- Yang R, Moosavi L. Prothrombin Time [Internet]. Treasure Island, Florida: StatPearls Publishing; Jan. 2023 [Accessed 21 Sept. 2023] Available from: https://www.ncbi.nlm.nih.gov/books/NBK544269/
- Prothrombin Time [Internet]. Rochester, NY: University of Rochester Medical Center; [Accessed 21 Sept. 2023] Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=pt_prothrombin_time
- Prothrombin Time - an overview [Internet]. ScienceDirect; [Accessed 21 Sept. 2023] Available from: https://www.sciencedirect.com/topics/medicine-and-dentistry/prothrombin-time
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