APTT (activated partial thromboplastin time) is a very important indicator of blood coagulation, which allows you to determine the risk of blood clots or bleeding. Correctly evaluating the work of the coagulation system, you can determine how severe the disease is and correctly select the treatment. Let's talk about it.
How is the APTT test performed?
The analysis of blood coagulation rate helps to identify systemic abnormalities, which usually indicate that there are violations of the quantitative and qualitative indicators of blood.
Such an analysis is carried out according to a certain scheme. First, the material that needs to be investigated is added to the test tube with an anticoagulant that binds calcium ions, because of which the blood does not clot. Centrifugation is performed to separate the plasma from platelets and other elements. After that, phospholipids, calcium chloride and an activator are added to the tube. They begin to evaluate the time during which a blood clot will form.
Phospholipids activate the external coagulation pathway, and calcium chloride is an important substance in the coagulation process. Such an analysis does not allow to fully evaluate the process of thrombus formation, but it helps to identify deviations in speed in order to subsequently look for the causes of this phenomenon.
Sometimes it turns out that the APTT is increased or decreased. This indicates existing problems in the body.
Rate indicator
The indicator is measured in seconds, and may differ due to nutrition, patient age and treatment. The norm of APTT for an adult is from 28 to 40 seconds. In newborns, this indicator is 1-3 seconds higher.
An increased APTT in the blood is diagnosed when any coagulation factor is reduced or increased by more than 30%. A reduced rate often indicates hypercoagulation.
The determination of APTT in adults and children is carried out to determine the causes of poor blood clots, as well as to evaluate the effectiveness of anticoagulant treatment.
Reasons for increasing APTT
Many are very upset when they find out that APTT is elevated. What does it mean? This happens when there is a risk of bleeding. The reasons for this may be:
- Insufficient amount of vitamin K in the body. This indicates problems in the digestive system, because this vitamin promotes the synthesis of intestinal bacteria. It is also essential for the normal operation of all coagulation factors. Its disadvantage arises from dysbiosis, with an aggressive diet, as a result of prolonged treatment with antibiotics.
- Genetic abnormalities that are associated with a violation of the quantitative and qualitative blood count. In this case, the APTT indicator is increased very much.
- Postpartum hemorrhage, acute leukemia, DIC.
- Hemophilia type A, B, C.
- The presence in the blood of antibodies against coagulation factors and lupus anticoagulant.
- Incorrect preparation for analysis, accidental ingress of heparin into the sample.
Increased APTT in a child may also be due to these reasons.
APTT during pregnancy
During pregnancy, the activated partial thromboplastin time begins to change. If the norm for an ordinary person is from 28 to 40 seconds, then in pregnant women it is 17-20 seconds. This means that it is declining. Such changes provoke the following factors:
- During this difficult period, an additional uteroplacental circulation circle appears in the woman’s body. The placenta consists of a large number of vessels. If even a slight detachment occurs, then blood loss can be quite significant. Usually, detachment occurs due to an increased tone of the uterus.
- During childbirth, a woman usually loses up to 400 ml of blood. This happens very quickly, and the coagulation system must be ready for such a heavy blood loss, so blood clots begin to form too quickly to prevent further blood loss.
Why is APTT elevated during pregnancy?
APTT is elevated if the coagulation time is more than 40 seconds. This leads to a decrease in the ability to form blood clots, resulting in a risk of large blood loss.
APTT is usually elevated if a pregnant woman takes antibiotics, heparin, aspirin, and thrombolytic drugs. Before taking tests, she should warn her doctor about this.
An increase in APTT indicates a decrease in the ability of blood to coagulate, and this happens with the following pathological conditions of the body:
- Diseases of the liver, wearing severe liver failure, including with cirrhosis. In this case, there is a violation of the synthesis of coagulation factors in the blood.
- Vitamin K deficiency arising from intestinal dysbiosis and also due to an improper diet.
- Leukemia
- Hemophilia type A, B, C. These are hereditary diseases characterized by congenital deficiency of coagulation factors, as a result of which spontaneous bleeding often occurs.
- Von Willebrand disease.
Conclusion
An aPTT test must be performed before the upcoming surgery to find out how quickly blood can clot. An increase or decrease from the norm indicates various pathologies. To avoid the risk of bleeding, appropriate treatment is carried out.