Activated partial thromboplastin time (APTT) - is one of the characteristics of the laboratory krovosvertyvayuschee human system that provides hemostasis by forming a fibrin blood clots. In normal clotting factors are in a passive state, in the form of inactive enzymes.
Damage to blood cells in pathologies leads to activation of these substances. APTT values in women by age and abnormality may be caused both by physiological factors, as well as serve as a symptom of serious illness.
The content of the article:
- 1 What does the analysis on the APTT
- 2 When the prescribed study
-
3 Norms of indicators by age
- 3.1 Among women
- 3.2 men
- 3.3 children
- 4 How to prepare for the study
- 5 How does the biomaterial fence
- 6 How to wait for the results of the study?
- 7 Explanation responses analysis
- 8 The causes of deviations of parameters from the norm?
- 9 How much is a study where they spend?
- 10 Techniques for normalization of
- 11 Video of the APTT in blood test
What does the analysis on the APTT
APTT, the rate of women over the age of which is considered in the article - the exact figure for the detection of bleeding disorders. SUMMARY analysis consists in determining the clotting time of plasma when activated natural process "in vitro" in the presence of special reagents.
APTT is a measure efficiency hemostasis of internal and common mechanism. In the first case, it occurs in the absence of tissue damage. To start an external mechanism that leads to the formation of a blood clot requires tissue factor.
At the final stage, these two mechanisms are combined (common pathway of coagulation), which eventually promotes the formation of thrombin and fibrin, "bridging" the vessel and impede blood loss. Subsequently, when there is a restoration of damaged tissues, is triggered reverse mechanism to facilitate thrombus dissolution.
When the prescribed study
Analysis to determine the APTT is prescribed in the following cases:
- Screening healthy people to detect the risk of disease.
- Analysis pathologies of blood coagulation. Breach of enzymic balance (including congenital) may result in diseases such as thrombosis (blockage of a blood vessel tear thrombus), ischemia and infarction of different organs, including brain; atherosclerosis and other cardiovascular diseases, immune diseases and cancer. When present, the patient requires periodic monitoring indicator APTT.
- Determination of disseminated intravascular coagulation (DIC), in which the body is abnormal process thrombus in small blood vessels, coupled with poor coagulability of blood, which leads to a massive hemorrhages. the disease is often asymptomatic.
- Diagnosis of hemophilia, which is genetically determined diseases. These people have an increased risk of high blood loss, even with minor injuries because the blood has a very low ability to curl. bleeding often occur in the joints, muscle tissue, internal organs and the brain. Increased bleeding with minimal damage is detected from the first days of life.
- Control of the state of blood in treating drug having anticoagulant action, in particular heparin. The latter is used for the treatment of patients diagnosed with venous thrombosis, pulmonary embolism, unstable angina, acute myocardial infarction, atrial fibrillation, DIC, Gasser's disease, mitral heart disease, inflammation of the heart muscle, and lupus glomerular nephritis. This drug is also prescribed as a preventive measure in operations with extracorporeal circulation, hemodialysis (blood cleansing) and certain other medical procedures.
- Detection of antiphospholipid syndrome - an autoimmune disease in which increased clotting activity that triggers blood clots. It is defined by the presence of lupus anticoagulant. In pregnant women, this pathology leads to an increased risk of spontaneous abortion, and thrombosis.
- Hageman diagnosis of the disease. This is a rare inherited disorder in which reduced activity of one of the clotting factors. It is characterized by the development of thrombosis or hemorrhagic syndrome.
- Diagnosis of von Willebrand disease. This is an inherited disease in which there are spontaneous bleeding due to deficient activity of one of the factors involved in the folding process. For this disease is characterized by prolonged bleeding that threaten the patient's life. One of the characteristic symptoms are bleeding from the mucous membranes of the mouth and nose, the spontaneous occurrence of marks on the skin due to violation of vascular permeability. Women are also seen heavy uterine bleeding lasting more than 10 days, as well as massive blood loss during delivery. Exacerbations may alternate with periods of relative well-being.
APTT, the rate among women whose age varies established within WHO, is also controlled during pregnancy every 3 months.
This is due to changes in hormone levels that affect the circulatory system, as well as an increased risk of complications (miscarriage, stillbirth, premature birth, pre-eclampsia) in those patients that have already been diagnosed in the pathology of coagulation system.
Norms of indicators by age
Normal aPTT value is 25-38 seconds. It depends on the characteristics of reagents, so that each laboratory by passing surveys indicate reference values contained in the passport medical diagnostic system.
This type of analysis is not standardized by the World Health Organization, since its use of various chemical compounds (animal or vegetable phospholipids, a mixture thereof; phospholipids derived from human blood cells). APTT Normal also classified by age of the patient, as this is no pronounced changes in the indicator.
Among women
A physiological change in the value of APTT may occur during pregnancy and menstruation. During this period the rate drops to 18 seconds. Very low value accompanied by the risk of blood clots in the vessels of the placenta, which may result in detachment and miscarriage.
At a high APTT may develop endometrial bleeding, which also threatens the life of the fetus and the woman.
men
For men, the rate remains the same - in the range 25-38 seconds. The conditions under which the reduction or increase in the rate APTT may occur are described below.
children
Norma activated partial thromboplastin time for the children corresponding to that of adults. However, in newborns, especially premature, it is characterized by an increase of 3-5 seconds.
How to prepare for the study
APTT is usually defined as part of the biochemical analysis of blood. Therefore, the general requirements for the preparation of the same. The norm in women over the age indicated on the same form, and where the values obtained.
In order to get the correct results, it is required to observe the following rules:
- taking biological material is produced in the morning on an empty stomach;
- Before any analysis of the last meal - for 8-14 h .;
- eve to avoid emotional and physical stress;
- 1-2 hours is necessary to give up smoking;
- It prohibited the use of alcohol for 2-3 days.
If the patient is taking anticoagulant drugs, it should be pre-notify the doctor as aPTT values while significantly distorted. In agreement with the doctor of their rule in a few days.
How does the biomaterial fence
The procedure for biomaterial sampling is as follows:
- The patient taking venous blood (usually from the elbow). To do this, impose a rubber band and asked to make a few surveyed clenching hands into a fist, to ensure the flow of blood.
- The biomaterial is placed in a tube containing the sodium citrate.
- The blood was centrifuged for 15 min.
- The assay is performed immediately or plasma is frozen to a temperature not higher than -20 ° C, the samples are fit for 2 months.
- To plasma was added the reagent (ellagic acid) with phospholipids.
- Count the time from the addition of reagents prior to clot formation. This is done manually or with the help of semi-automatic coagulometers.
How to wait for the results of the study?
Results of the study can be obtained on the same day. In the simultaneous assessment of other indicators of blood, you need to transport biological material to another laboratory, the duration can be increased to 48 hours.
The period between taking the sample and the assay should not exceed 1 hour. This requirement is due to the decay period of heparin.
Explanation responses analysis
Interpretation of assay results and the possible diseases are reflected in the table below:
| Norm | Shortening the time of APTT | Lengthening the time of APTT |
| 25-38 seconds. for all age groups | The risk of thrombosis and thromboembolism Metastasis of tumors of different localizations It is not diagnostically valuable indicator |
|
An accurate diagnosis is established by the attending physician based on medical history and the results of other instrumental and laboratory examinations.
The causes of deviations of parameters from the norm?
APTT, the rate of women over the age of which is shown in the article can be changed by the following factors.
The elongation of the test results:
- massive blood transfusion;
- receiving (introduction) of heparin and its analogs, streptokinase;
- insufficient anti-coagulant or the filling tube (laboratory error).
The shortening of the coagulation time:
- acute blood loss;
- contamination biomaterial sample tissue proteins when taking blood from a vein.
Application specific reagents in the research process could "push" the normal aPTT value to 22 seconds. downward and up to 45 seconds. upwards. Therefore, each laboratory make their own therapeutic ranges.
Changes of APTT at diseases krovosvertyvayuschee system occurs with a decrease or increase the level of factors of 30-40%. As there may be false positive results, the tests in some cases it is recommended to take again.
How much is a study where they spend?
It refers to APTT tests, which are basic for each initial evaluation of patients. Analysis can be taken in any certified laboratory, since the procedure is simple and easy to carry.
The survey produced both in public and in private clinics.
Its value depends on the pricing policy of the laboratory, such as the reagents and complex estimated blood factors. The average price of commercial clinics in the range of 190-290 rubles., Thus it is necessary to take into account the additional cost of taking the biomaterial (110-250 rub.).
Techniques for normalization of
Methods for normalization of the aPTT depend on the disease diagnosed.
A brief review of methods of treatment described in the table below:
| Disease | Features | therapies |
| von Willebrand's disease | Treatment depends on the type of disease | Factor VIII Preparations desmopressin |
| Hemophilia | pathology is incurable It is monitored by injecting the missing clotting factor |
Or transfusion of fresh frozen plasma, antigemofiliynaya plasma cryoprecipitate concentrate of coagulation factors |
| DIC | Can occur suddenly in shock, profuse blood loss, poisoning, sepsis, patients with obstetric pathologies and other conditions | Blood transfusion Intravenous heparin Acetylsalicylic acid Introduction of glucocorticoids, dopamine and opioids to patients in a state of shock |
| thromboembolism | Patients in need of urgent hospitalization | Intravenous heparin symptomatic therapy |
| Thrombosis | The low-cholesterol diet is recommended as a prevention, statins, anticoagulants | In the event of acute conditions - receiving anticoagulants, fibrinolytic agents, surgery |
APTT coagulation referred to indicators that are analyzed to assess blood clotting. The norm in women over the age of constant value. Carrying out this type of analysis allows time to detect abnormal changes in the blood and prescribe additional clarifying examinations.
Registration of the article: Lozinski Oleg
Video of the APTT in blood test
Analysis coagulation in normal and variances:
