There are various clotting factors in the body that work together to stop bleeding and take part in clotting. A problem with any one of these can lead to a prolongation of the bleeding time, the time it takes for a clot to form. The aPTT test is a test to know how well certain clotting factors are working. It is known as a screening test that checks for the absence of all clotting factors except factors VII and XIII.
It is usually performed together with another blood test called prothrombin time (PT). The prothrombin time test is a different test that measures the ability of the blood to clot and is particularly sensitive to factor VII.
The PTT test is a blood test to measure the time it takes for blood to clot. A form that measures the same time, but with a substance added to the liquid blood so that clotting occurs faster, is called aPTT. There are various levels of clotting factors in the blood. If there is a deficiency or defect in any of these, it may take longer than normal for the blood to clot. This test helps to keep the function of clotting factors under control.
What Does the aPTT Test Do?
APTT is a blood test that determines the condition related to blood clotting time. The aPTT test is used for the following purposes;
To check the function of specific clotting factors: If one of the relevant factors is absent or defective, the individual has a bleeding problem. Hemophilia is one of these disorders.
Checking for problems with the immune system: Some autoimmune disorders that cause the immune system to wage war against clotting factors are characterized by clotting problems.
Monitoring patients who need to take heparin: In some disorders, blood clots form above normal levels. Abnormal clots that form outside of this condition can cause blockage of blood vessels and cause serious health problems such as heart attack or stroke. Heparin is usually used to prevent these abnormal clots from forming. However, using more heparin than is necessary can lead to heavy and risky bleeding. Therefore, the time of clot formation should be monitored with the aPTT test and the dose should be adjusted.
When is the aPTT test performed?
This test may be needed if the specialist suspects a problem with one or more clotting factors. For example, if there is a bleeding disorder, such as Von Willebrand's disease, or if there is another condition that prevents blood clotting, this test helps to identify where the problem lies. The aPTT test may be needed in the following cases;
- Heavy bleeding that cannot be determined
- Simple bleeding, bruising and bruising of the body
- Blood in feces or urine
- Simple bleeding in the gums
- Menstrual cycle with heavy bleeding in women
- Pain and swelling in the joints
- Persistent nosebleeds that do not stop easily
- Clot formation inside the vessel
What is low aPTT?
It is rare for PTT or aPTT to be low with values below the usual reference range. It is therefore recommended that a new test be performed to rule out the possibility of heparin contamination of the blood sample or any other measurement problem.
What is an elevated aPTT?
Bleeding occurs in the body when the Aptt value, which is considered to be in the usual reference range of 26 to 35, reaches 100 and above. This condition, which causes impaired clotting, results in heavy bleeding or late stopping of bleeding.
What should be the normal aPTT value?
The usual reference ranges vary according to various laboratories. It is therefore necessary to discuss the meaning of the ratios with a specialist. A typical value for PTT is 60 to 70 seconds. aPTT measures the same thing, but in this test a substance is added to the blood to make it clot faster. The specific value here is between 25 and 35 seconds. If the test is performed because the patient is taking heparin, the PTT is in the range of 120 to 140 seconds, while the aPTT should be in the range of 60 or 80 seconds.
How is the aPTT Test Performed?
The aPTT test, like most other blood tests, is performed with a blood sample taken from the vein with a syringe. Blood is generally taken from a vein located on the underside of the elbow or the back of the hand. The blood sample is sent to the laboratory in a tube with a blue cap.
What are the Symptoms of aPTT Elevation?
Many findings are looked at when blood tests are performed. One of the conditions looked at during the blood test is the aptt finding. Some of the symptoms of aPTT excess are as follows;
- Recurrent bleeding conditions
- Easy bruising of the body
- Blood in feces or urine
- Recurrent bleeding in the gums
- Menstrual periods with heavy bleeding in women
- Pain and swelling in the joint area
- Recurrent prolonged nosebleeds
In which cases does aPTT prolongation occur and what are the symptoms?
These conditions include recurrent miscarriages, leukemia, malnutrition, various liver disorders, liver problems, intense blood loss during childbirth. In addition, APTT time is prolonged in common intravascular coagulation events called DIC.
aPTT Test Usage Areas
With the aPTT test, the time of clot formation is monitored and the dose is adjusted.
This test has some areas of use. We can list these areas as follows;
- Examination of the clot formation system
- Monitoring anticoagulant therapy and adjusting the dose of medication
- Screening for clot formation
- Investigation of liver failure
- Investigation of vitamin K deprivation