Summary

• The coagulation profile is a group of tests that shows how well your blood is clotting. 
• It is used to diagnose a bleeding or clotting disorder, or to monitor anticoagulation therapy such as warfarin or similar anti-clotting medications.
• It can also be used before you have surgery in certain circumstances, such as if you have a history of bleeding or are at risk of heavy bleeding or clotting because of an underlying condition. This is to assess your risk of potential bleeding or clotting problems during the operation.

What tests will you have if you have clotting or bleeding problems?

If your medical team suspects you may have a clotting or bleeding problem one or both of two tests are usually ordered. These are: 

• APTT
• PT/INR

It is likely that you will also have a Full blood count.

If the results of these tests are not normal, a range of different tests can be used to gain further information.  The choice of tests will depend on what your medical team is investigating but you could expect to have some of these tests:

• Thrombin time
• Platelet count (this would have been part of the full blood count)
• Coagulation factor assays
• D-dimer
• Fibrinogen

Other tests that are often done at the same time include:

• Liver function tests 
• Kidney function tests

Why get tested?

Your medical team may request a coagulation profile:

• If it is possible that you have a bleeding disorder such as if you have unexplained bruises, or you take an unusually long time to stop bleeding from a small cut or wound.
• If you are taking an anti-coagulant (blood thinner) medication such as warfarin.
• If you develop a blood clot within a blood vessel for no apparent reason.

Conditions that cause bleeding or clotting problems include:

• liver disease
• pregnancy-related eclampsia
• vitamin K deficiency
• cancer or cancer treatment
• autoimmune disorders
• sepsis
• infections
• obesity (blood clots)

There are several rare inherited disorders that affect clotting. Testing is done if an inherited factor deficiency is suspected, especially when bleeding episodes begin early in life or when a close relative has been diagnosed with an inherited factor deficiency.

How blood clotting works

• Clotting is a normal part of healing. When you have an injury, and a blood vessel starts to bleed, your body triggers a series of interactions to make a blood clot to stop the bleeding.
• Platelets (thrombocytes) are tiny plate-shaped cells that circulate in your blood. When they sense damage to a blood vessel, they travel to the area where they change their shape by growing long tentacles, become sticky and clump together.
• When activated, platelets release chemicals to attract more platelets and other cells, setting off the next step. This is called the coagulation cascade.
• Proteins called coagulation (clotting) factors are activated one after the other, then threads of a protein called fibrin are produced. These threads stick to each other to form a fibrin net that catches the sticky platelets and hold them together to form a clot.
• Once a clot is formed, other substances are activated to slow the clotting process. As the tissue heals and you don't need the clot anymore, the fibrin strands dissolve.

Coagulation (blood clotting) factors

Your liver makes most of your coagulation (clotting) factors.  Coagulation factors have names, such as fibrinogen and prothrombin. Each factor has been given a number, a Roman numeral, such as coagulation factor I or II or VIII.  For more information on coagulation factors and how they make blood clots, go to Coagulation (blood clotting) factors.

What is the coagulation profile?

A typical coagulation profile

The coagulation profile will typically include some of these tests, but which tests will depend on your clinical history and depend on what your medical team is investigating. 

Having the test

Sample

Blood.

Preparation
None.

Your results

Your initial PT and APTT results can show whether there is a problem with the coagulation process and where the problem is in the pathway.

• If the APTT is abnormal and the PT/INR is normal, you may have deficiencies of factors VIII, IX, XI or XII.
• If the APTT is normal and the PT/INR is prolonged, you may have a deficiency of factors VII.
• If both PT and APTT are abnormal, you may have deficiencies in the common pathway (I, II, V, X) or deficiencies to multiple factors.

The results of these tests will guide your medical team as to whether further testing is required including specialised tests of the individual factors. See Coagulation factors for more details.

Reading your test report

Your results will be presented along with those of your other tests on the same form.  You will see separate columns or lines for each of these tests.

Reference intervals 

Your results will be compared to reference intervals (sometimes called a normal range).

• Reference intervals are the range of results expected in healthy people.
• When compared against them your results may be flagged high or low if they sit outside this range.
• Many reference intervals vary between labs so only those that are standardised or harmonised across most laboratories are given on this website.

If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.

Questions to ask your doctor

The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking including Chinese medicines or supplements. Find out if you need to fast or stop any particular foods, medications or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?

More information

Pathology and diagnostic imaging reports can be added to your My Health Record.

You and your healthcare provider can now access your results whenever and wherever needed. Get further trustworthy health information and advice from healthdirect.