Thrombin: how to measure it and what it is for


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Blood is one of the most important elements in our organism, practically our source of life. In addition to transporting oxygen to nourish all the cells in our body, it also ensures that wounds close and do not become infected, among many other functions. The platelets found in the blood are responsible for forming the clot, plugging the cut that has been made in the skin and preventing bleeding, as well as healing it,

This is why it is so important to check that the blood coagulates correctly. The thrombin test is used to detect whether the blood performs this function correctly or whether there is a problem that hinders its mission. How is it done? Do the results take a long time to arrive? Let’s see what exactly this test is and what thrombin itself is.


What is thrombin?

Thrombin is an enzyme that is part of the blood clotting process, so it is already in the blood. It acts on fibrinogen to create fibrin, a fibrous protein that aids in blood clotting.

When we cut ourselves and bleed, the body starts to work to stop the bleeding and make us lose as little of this liquid as possible. To do this, platelets, cell fragments also present in the blood, join together and go to the focus of the lesion. This is when the coagulation process begins, in which the coagulation proteins are activated.

A normal, stable clot requires platelets and clotting factors to be functioning normally and the blood to have enough of them for the wound to close. When there is too little of 1 or more of these factors or platelets, coagulation cannot take place. As a result, the wound does not ‘plug’ and bleeding episodes or poor clotting, known as thrombosis, occur.

Thrombin time is the test that measures the part of the hemostatic process in which fibrinogen is converted to fibrin. Exactly, its mission is to measure the time it takes for the body to form a fibrin clot when a normal amount of thrombin is added to the plasma.

This time depends on the amount of fibrinogen and the presence of possible inhibitors, such as heparin. If thrombin is added to the sample, the other coagulation factors are not taken into account, but only the function of fibrinogen. TP or TTP coagulation tests base their results on the process that takes place in the laboratory, so it is not possible to observe what is actually happening in the body.

Most people with low fibrinogen or dysfunctional fibrinogen do not reveal symptoms of any kind, and if they do they are so mild and general that they can be mistaken for those of another disease. Diagnosis, which is so important when it comes to preventing or catching diseases in time and minimizing their effects on the body as much as possible, is very difficult to perform.

In fact, the thrombin test is usually performed because something strange is detected in a blood test that is performed for another reason or the patient sees that he or she is suffering from unexpected or prolonged bleeding after a surgical intervention. It is even believed that some miscarriages may be due to or related to improper clotting in the placental blood vessels.


How is the thrombin test used?

Thrombin time (TT) testing is usually performed when there is suspicion of a coagulation irregularity or inadequate clot formation, especially in thrombotic episodes, with the objective of assessing the concentration and functionality of fibrinogen. Today, most of the laboratories, among which we can find AmbarLab, provide the possibility of testing for fibrinogen.

It should be noted that the thrombin time test is very sensitive to the anticoagulant heparin, so it is often used to monitor unfractionated heparin therapy and to see if there has been heparin contamination in a blood sample. It is still used for these purposes today, but this test has been almost entirely replaced by other tests and procedures to neutralize heparin.

This test simply requires a blood sample, obtained from a vein in the arm or hand. To prevent clotting, the sample is placed in a tube with a chemical substance that prevents this process.


When is it requested?

The TT test is usually ordered by the physician either alone or with other tests when a patient has unexplained or unusual bleeding or clotting, if a person has repeated miscarriages, or if there is a prolongation of the results on the primary coagulation tests (PT or TTP).

Another situation in which a thrombin time test is requested is when the health professional suspects a disorder related to a decrease in the amount of fibrinogen or a possible dysfunction. There are also occasions when this test is assigned if heparin contamination is suspected in a specimen or if a person is on heparin therapy. These 2 cases, however, have greatly diminished in recent decades.

If your doctor assigns you a thrombin test, it is essential to report any medications you are currently taking, especially if any of them affect blood clotting. You should know them all, from herbal medications, vitamins and supplements, prescription and over-the-counter (including, of course, any illegal drugs you are taking). When talking about health, especially your own health, you have to lay all the cards on the table before the doctor so that he can prescribe an appropriate treatment that does not put your health at risk, hence hiding some information from him is more detrimental to you than anything else.

This test is also often ordered to help diagnose the following problems:

  • Hereditary conditions that generate a low level of fibrinogen or its disorder.
  • Liver diseases (cirrhosis or hepatitis).
  • Some types of cancer (kidney cancer, liver cancer or multiple myeloma).
  • Specific conditions (lupus, ulcerative colitis…).
  • Antibodies against fibrinogen that could be naturally generated by the body if the patient has undergone surgery in which bovine fibrin surgical glue has been used.
  • Disseminated intravascular coagulation.
  • As a control before undergoing a surgical procedure.


What does the result mean?

The results have to be measured taking into account the patient’s age, sex and medical history, among other factors, so there is no ‘ideal result’. What’s more: these may vary depending on the laboratory where the test is performed.

The normal or usual thrombin time is 12 to 19 seconds. If the time is higher, we may be dealing with a high or low fibrinogen level or fibrinogen may not be functioning as usual. In any case: there is an irregularity, which may be due to a malfunction of the enzyme or due to some medication that affects blood coagulation (heparin, argatroban…).

If the thrombin time exceeds 12-19 seconds, the cause may be proteins in the blood from multiple myeloma, amyloidosis or antibodies against bovine thrombin, which are used as part of the tests.

No treatment is usually needed to combat an irregularity in the amount of fibrinogen, unless significant bleeding is detected. In this case, fibrinogen is usually replaced by administering it in the form of cryoprecipitate or fresh frozen plasma for a short time. If coagulation problems are more recurrent, therapy with anticoagulants (acenocoumarol or Sintrom®) can be administered.


What other tests do you do?

If your doctor orders the thrombin time test, he or she may also order other tests in order to get a broader picture of your blood’s ability to clot, such as:

  • Reptilase time. It measures the time it takes for fibrinogen to convert to fibrin, so it is possible to know if this extended period of thrombin is caused by heparin.
  • Prothrombin time. We can get information from fibrinogen and other parts of the blood that help clot formation. This test is also performed to analyze the effects of warfarin.
  • Activated partial thromboplastin time. Information can be obtained on factors in blood coagulation and to measure the effects of heparin.


Is the thrombin time useful for monitoring dabigatran treatment?

This thrombin inhibitor acts directly and is one of the oral anticoagulants approved in recent years. It does not have to be monitored on a daily basis, although it is recommended if the patient has certain clinical conditions. What is highly suggested is the use of thrombin time or modified dilute thrombin time to monitor dabigatran treatment. Even so, this procedure has not been widely accepted, so whenever monitoring is indicated in the patient, correct and accurate measurement of dabigatran levels should be performed.

As you can see, thrombin and its analysis can shed light on the reason for irregular coagulation in a patient. That is why prevention and a correct analysis are so important to detect what is happening and provide the appropriate treatment. That’s what drives us at AmbarLab, the peace of mind of having with you a laboratory with more than 3,000 tests, capable of accompanying you in the management of your business and in the development of new projects.

If you have any more specific questions about the thrombin time test or any other aspect of our laboratory, please do not hesitate to contact us. us. Our expert team will be happy to advise you on any of our services.

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