In recent years, cases of autoimmune pathologies have become more frequent. One such disease is rheumatoid arthritis. A blood test for ADC helps with high accuracy to identify this ailment in the early stages. This allows you to start treatment in a timely manner, achieve stable remission and avoid serious complications. The full name of this diagnostic method is an antibody test for a cyclic citrulline peptide.
What is an analysis
What does a blood test for ATsP show? With rheumatoid arthritis, a serious malfunction in the body's defenses occurs. The immune system mistakenly defines articular membrane cells as foreign proteins. Enhanced production of antibodies against their own healthy tissues begins.
As a result, the joint membrane is gradually inflamed in a person. As the pathology progresses, cartilage is destroyed and bone tissue is deformed. The disease is accompanied by severe arthralgia. The patient is concerned about acute pain in the affected joint. In advanced cases of pathology, disability occurs.
The cyclic citrulline peptide is normally present in a healthy human body. However, it is not involved in the metabolism and is rapidly removed through the kidneys. In a patient with rheumatoid arthritis, the content of this protein in the body is increased. As a result, the immune system recognizes the peptide as foreign. It produces antibodies against protein, their number can be determined using a blood test for ADC.
Rheumatoid factor test
For arthritis of autoimmune origin, doctors prescribe another analysis. This is a blood test for rheumatoid factor (RF). However, this diagnostic method is less accurate. RF at the beginning of the disease is detected only in half of the cases. With the help of this study, it is not always possible to identify the early stages of pathology. In addition, the rheumatoid factor can be positive not only for autoimmune diseases. Such a result is possible with tuberculosis, tumors, liver pathologies.
Benefits of Antibody Assay
A blood test for ATsP in 80% of cases reveals the disease at an early stage, and the accuracy of its results is 98%. The formation of antibodies to the peptide is a major marker of autoimmune pathology. Sometimes, using this diagnostic method, rheumatoid arthritis can be recognized even before the onset of clinical symptoms.
Indications for appointment
This examination is quite expensive. It is carried out using a complex enzyme-linked immunosorbent assay. Therefore, the doctor prescribes such a diagnostic method only if:
- persistent pain in the joints lasting at least 2 months;
- stiffness in the joints in the morning;
- signs of bone inflammation;
- genetic predisposition to autoimmune pathologies;
- cysts in bone tissue on an x-ray;
- deviations from the norm in a biochemical blood test.
This study allows you to start treatment in a timely manner and to avoid stiffness and deformation of the joints.
Analysis preparation
Diagnosis is by taking biomaterial from a vein. After 1-3 days, the patient receives a form in his hands with a transcript of a blood test for ATsPs. In order for the test indicators to be reliable, it is necessary to adhere to the following rules for preparing for the examination:
- The analysis is taken strictly on an empty stomach. The last meal is allowed no later than 8-12 hours before blood sampling. On the day of the examination, you can only drink water.
- About 3 days before the diagnostic test, you need to stop eating spicy, fatty and fried foods, as well as alcoholic beverages.
- A few days before the blood donation, you must stop taking dietary supplements.
- It is important to avoid physical stress for 12 hours before analysis. Also, during this period, physiotherapeutic procedures should not be done.
Deciphering the results
It is important for each patient to understand the decoding and norm of a blood test for ATsPs. If a small amount of antibodies is found in the results of the study, then this does not always indicate pathology. Such immunoglobulins may also be present in a healthy person, but very few are formed. The number of antibodies is measured in units of 1 liter of blood (U / ml).
If a person has an antibody score of 3 to 5 U / ml, then the result is considered negative. This is the norm of a blood test for ADC. This result indicates the absence of pathology.
Indicators of more than 5 units / ml, but less than 17 units / ml indicate abnormalities in the immune system. This result is called weakly positive. This does not always indicate rheumatoid arthritis. Antibodies can be elevated in systemic lupus erythematosus, Crohn's disease, and other autoimmune pathologies. In this case, rheumatologists prescribe additional studies to clarify the diagnosis.
If the antibody values exceed 17 U / ml, then the patient is diagnosed with rheumatoid arthritis. This is a positive analysis result. However, this should take into account the small probability of distortion indicators. A false positive test result can be noted with an increase in bilirubin, hypergammaglobulinemia, the presence of a large amount of fat in the blood (lipemia). The intake of vitamin B7 (biotin) can also distort indicators. If all of the above factors are absent, then, most likely, a person is sick with rheumatoid arthritis.
It often happens that a study on the rheumatoid factor showed a positive result, and a blood test for ATsPs did not reveal the disease. In this case, experts trust the results of screening for antibodies to a specific peptide, as a more accurate diagnostic test.
What if an antibody test shows a positive result? In this case, it is urgent to contact a rheumatologist and undergo a course of treatment. Modern methods of therapy will help achieve persistent and prolonged remission, as well as prevent severe complications.