The coagulogram is a group of blood tests ordered by your doctor to evaluate the blood clotting process, identify changes, and indicate the person’s treatment to avoid complications.
This test is mainly requested prior to surgery to assess the patient’s risk of bleeding during the procedure, for example, and includes bleeding time, prothrombin time, activated partial thromboplastin time, thrombin time and evaluation of the number of platelets.
- The coagulogram is indicated mainly before surgery.
- But it can also be requested by the doctor to look for the cause of hematological diseases and check the risk of thrombosis.
- Especially in women who use contraceptives.
In addition, the coagulogram is indicated after the bite of an animal that has a toxin that can interfere with the clotting process and in the follow-up of people using anticoagulants, such as heparin and warfarin, for example.Know other blood thinners and when they’re indicated.
The coagulogram should be performed with the fasting person for 2 to 4 hours and involves taking a blood sample that is sent for testing, with the exception of Bleeding Time (TS), which is performed at the site and involves observing the time needed to stop the bleeding.
It is important that the use of anticoagulants is known before the test, as it may interfere with the outcome or be taken into account during the test, for example, it is important to have medical advice regarding discontinuation of use.drug before performing the coagulogram.
The coagulogram consists of tests that evaluate the presence of all the factors involved in blood clotting and, therefore, hemostase, which corresponds to the processes that occur within the blood vessels that aim to retain blood fluid to prevent the formation of clots.or bleeding Understands everything about hemostase.
The main tests present in the coagulogram are
This test is usually requested as a way to complete the other tests and is useful for detecting any platelet changes and is done by making a small hole in the ear, which corresponds to Duke’s technique, or by cutting the forearm, called Ivy’s technique.and then counting the bleeding downtime.
To perform Ivy’s technique, pressure is applied to the patient’s arm and a small incision is made at the site; In the case of Duke’s technique, the hole in the ear is made by a disposable lancet or stylus.Bleeding is evaluated every 30 seconds using a filter paper, which absorbs blood from the site.The test ends when the filter paper no longer absorbs blood.
Thanks to the result of TS it is possible to assess hemostasis and the presence or absence of von Willebrand factor, a factor present in platelets that plays a fundamental role in the blood clotting process, although this test is useful for detecting changes in hemostasis, can cause discomfort especially in children, since the test can be performed by making a hole in the ear For example.
How to understand the result: After drilling the hole, the doctor or technician responsible for the examination counts the clotting time of the blood and monitors it using a filter paper that absorbs the blood from the site.When the filter paper no longer absorbs the blood blood, the test is If the test was performed using the ivy technique, which is the arm, the normal bleeding time is between 6 and 9 minutes, in the case of the Duke technique, which is the ear, the time normal bleeding is 1 and 3 minutes.
When the time is longer than the reference time, it is indicated in the extended TS test, indicating that the clotting process took longer than normal, which may be indicative of von Willebrand disease, the use of anticoagulants or thrombocytopenia, for example.causes of thrombocytopenia.
Prothrombin, also known as coagulation factor II, is a protein that is activated during the coagulation process and whose function is to promote the conversion of fibrinogen into fibrin, forming the secondary or permanent platelet cap.
This test is designed to test the functioning of the extrinsic coagulation pathway, as it involves evaluating the time it takes for the blood to form the secondary buffer after exposure to calcium thromboplastin, which is the reagent used in the test.
How to understand the result: Under normal conditions, after contact of the blood with calcium thromboplastin, the extrinsic pathway is activated, with the activation of coagulation factors VII and X and, therefore, of factor II, which is prothrombin, favoring the conversion of fibrinogen.fibrin, stopping the bleeding. This process usually takes between 10 and 14 seconds.
However, in some situations, the coagulogram detects an enlarged TP, which means that prothrombin activation occurs longer than normal. An increase in TP values usually occurs when anticoagulants, vitamin K deficiency, factor VII deficiency, and liver problems are used, for example, because prothrombin occurs in the liver.
In rare cases, TP may be reduced, such as the use of vitamin K supplements or estrogen birth control pills, for example.Learn more about the prothrombin time test result.
This test is also used to evaluate hemostase, but can be used to check for the presence or absence of clotting factors present in the intrinsic pathway of the coagulation cascade.
TTPA is generally important for monitoring patients who use heparin, which is an anticoagulant, or who have blood clotting problems, which is useful for identifying changes related to clotting factors.
During this test, a sample of extracted blood is exposed to the reagents and then calculated the time required for blood clotting.
How to understand the result: Under normal conditions, the TTPA is 21 to 32 seconds; however, when the person uses anticoagulants, such as heparin, or has a deficiency of specific intrinsic factors of the pathway, such as factors XII, XI or VIII and IX, which indicate hemophilia, the delay is generally longer than the reference time., being indicated in the review that APTT extends.
The time of thrombin corresponds to the time required for the formation of the clot after the addition of thrombin, which is the coagulation factor necessary for the activation of fibrinogen in fibrin, which guarantees the stability of the clot.
This test is very sensitive and is performed by adding thrombin to low concentrations in the blood plasma, the clotting time is influenced by the amount of fibrinogen present in the plasma.
How to understand the result: Normally after adding thrombin to the plasma, the clot forms between 14 and 21 seconds, which is considered the reference value, which may vary depending on the lab in which the test is performed.
TT is considered prolonged when the person uses anticoagulants, has fibrin degradation products, and has a factor XIII or fibrinogen deficiency, for example.
Platelets are cell fragments in the blood that play a fundamental role in hemostasis because they contain important factors for the coagulation process, such as von Willebrand factor, for example.
When there is tissue damage, platelets move quickly to the site of the injury, with the aim of assisting in the process of stagnation of the blood.Activated platelets adhere to the endothelium of the injured vessel using the von Willebrand factor, then alter their formation and release substances into the plasma to recruit more platelets at the site of the lesion to form the platelet plug.Primary.
Therefore, controlling the amount of platelets is important in the coagulogram because it allows the doctor to know if there is a change in the primary hemostase process, recommending a more specific treatment.
How to understand the result: The normal amount of platelets in the blood is between 150,000 and 450,000 / mm3.Values below the reference value are indicated on the test as thrombopenia, indicating that there are fewer circulating platelets, which can cause blood clotting problems., favoring bleeding, in addition to being able to indicate nutritional deficiencies, bone marrow alterations or infections, for example.
Values above the reference are called thrombocytosis, which can lead to excessive clotting, which can occur due to lifestyle habits, such as smoking or alcoholism, for example, or due to pathological conditions, such as iron deficiency anemia, myelodial syndrome and leukemia, for example.For example, learn about the other causes of platelet enlargement.