APTT (activated partial thromboplastin time) is a very important indicator of blood clotting, which allows you to determine the risk of blood clots or bleeding. By correctly evaluating the work of the coagulation system, you can determine how severe the disease is and choose the right treatment. Let's talk about it.
How is the APTT test performed?
The blood clotting rate test helps to detect systemic abnormalities, which usually indicate that there are violations of quantitative and qualitative blood parameters.
Such an analysis is carried out according to a certain scheme. First, the material to be examined is added to a test tube with an anticoagulant that binds calcium ions, which prevents blood from clotting. Centrifugation is carried out to separate the plasma from platelets and other elements. After that, phospholipids, calcium chloride and an activator are added to the test tube. They begin to estimate the time it takes for a blood clot to form.
Phospholipids activate the extrinsic coagulation pathway, and calcium chloride is an essential ingredient in the processcoagulation. Such an analysis does not allow to fully assess the process of thrombus formation, but helps to identify deviations in speed in order to subsequently look for the causes of such a phenomenon.
Sometimes it turns out that the APTT is increased or decreased. This indicates existing problems in the body.
Normal indicator
The indicator is measured in seconds, and may differ due to nutrition, patient age and ongoing treatment. The normal APTT for an adult is 28 to 40 seconds. In newborns, this indicator is 1-3 seconds higher.
Elevated APTT in the blood is diagnosed when any coagulation factor is reduced or increased by more than 30%. A low reading often indicates hypercoagulability.
APTT testing in adults and children is performed to find out the cause of poor blood clotting, as well as to evaluate the effectiveness of anticoagulant treatment.
Reasons for increased APTT
Many are very upset when they find out that the APTT is elevated. What does it mean? This happens when there is a risk of bleeding. The reasons for this may be:
- Not enough 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 functioning of all clotting factors. Its deficiency occurs due to dysbacteriosis, with an aggressive diet, inthe result of long-term antibiotic treatment.
- Genetic anomalies that are associated with a violation of the quantitative and qualitative indicators of blood. In this case, the APTT is very high.
- Postpartum haemorrhage, acute leukemia, DIC.
- Hemophilia types A, B, C.
- Presence in the blood of antibodies against clotting factors and lupus anticoagulant.
- Incorrect preparation for analysis, accidental release of heparin into the sample.
Increased APTT in a child may also be due to these reasons.
APTT during pregnancy
During pregnancy, activated partial thromboplastin time begins to change. If the norm for an ordinary person is from 28 to 40 seconds, then for pregnant women it is 17–20 seconds. This means that it is decreasing. Such changes provoke the following factors:
- During this difficult period, an additional uteroplacental circle of blood circulation appears in a woman's body. The placenta is made up of a large number of blood vessels. If even a small detachment occurs, then blood loss can be quite significant. Usually, detachment occurs due to increased uterine tone.
- During childbirth, a woman usually loses up to 400 ml of blood. This happens very quickly, and the clotting system must be ready for such a strong blood loss, so blood clots begin to form just as quickly to prevent further blood loss.
Why is APTT elevated during pregnancy?
APTT is elevated if the clotting time is greater 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 is taking antibiotics, heparin, aspirin, and thrombolytic drugs. Before taking tests, she must notify her doctor about this.
An increase in APTT indicates a decrease in the ability of blood to clot, and this occurs under the following pathological conditions of the body:
- Liver diseases that cause severe liver failure, including cirrhosis. In this case, there is a violation of the synthesis of coagulation factors in the blood.
- Vitamin K deficiency caused by dysbacteriosis in the intestines, as well as due to improper diet.
- Leukemia.
- Hemophilia types A, B, C. These are hereditary diseases characterized by congenital deficiency of clotting factors, resulting in frequent spontaneous bleeding.
- Willebrand disease.
Conclusion
An APTT test is a must before an upcoming operation to find out how fast the blood can clot. An increase or decrease from the norm indicates various pathologies. Appropriate treatment is given to avoid the risk of bleeding.
