What are antinuclear antibodies?

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Antinuclear antibodies (ANA) are antibodies that are not present in the body of normal people, have the ability to bind to certain structures inside the cell nucleus. The nucleus is the inner core of the cell that does not have DNA as genetic material.

1. What are antinuclear antibodies?

Antinuclear antibodies are used in the diagnosis of systemic lupus erythematosus (SLE) and other autoimmune diseases. Some antibodies in this group are specific only for systemic lupus erythematosus, others are specific for other autoimmune diseases. Antinuclear antibodies can be found in people whose immune system can cause inflammation against their body's tissues (also called autoimmune disease). Antibodies found against your own tissues are called autoantibodies.
Quantitative testing of antinuclear antibodies is performed by various assays (indirect immunofluorescence, enzyme-linked immunosorbent assay [ELISA]) and the results are analyzed via 1 titers calculated by indirect immunofluorescence (in positive cases). A low antibody titer would be considered negative, while an increased titer would be diagnosed as positive and indicate a high concentration of antinuclear antibodies.
Quantitative antinuclear antibody test detects antinuclear antibodies in the blood. The normal immune system causes the body to produce antibodies to help fight infections. However, antinuclear antibodies usually attack the body's own tissues - specifically targeting the nucleus of each cell. Quantitative antinuclear antibody testing recognizes that the immune system has launched a misplaced attack on its own tissue - in other words, an autoimmune response.
Doctors may order a quantitative antinuclear antibody test if they suspect an autoimmune disease such as lupus, rheumatoid arthritis, scleroderma. A positive antinuclear antibody (ANA) result ( + ) indicates that you have an immune system disease or systemic lupus erythematosus. The test value can be ( +) or ( ++) from time to time. If the disease is more severe or progressing, it is equivalent to more positivity (+).

2. Quantification of antinuclear antibodies

2.1. Specimen collection and sample handling Specimen must be properly collected into a standard non-anticoagulant test tube (serum tube) or using a tube containing Li-Heparine, EDTA anticoagulant. Specimens were received from clinical departments and clinic sampling departments. The staff receiving the samples took the patient information from the hospital management software or the information that the nurse at the clinical department wrote on the test tube, then centrifuged it for 4000 rpm for 5 minutes before conducting the test. Storage of serum and plasma specimens: Samples are stable for 8 hours at 15-25°C, 1 day at 2-8°C, 28 days at -20°C. Frozen only once. Store standards, QC after being reconstituted at -20°C. When running, keep at room temperature (20-25°C) until completely defrosted and shake well before testing. experience. 2. Technical implementation The test machine and chemicals have been calibrated before performing the analysis. Quantitative antinuclear antibody titers are stable for 28 days and a calibration should be performed every time a reagent lot is changed. Quality check is within allowable limits. Normally run 2 levels of internal control (QC) per day: normal and abnormal. Compare with the law on quality control, if passed, analyze the sample.
Put the specimen into analysis according to the protocol of the machine. When the results are available, analyze and compare them with the test sheets, return and save the results to the network system, print the test result sheets and return the results to the patient on time.
Periodically: Re-calibrate and run 2 QC levels after changing a new batch of reagents or after servicing or repairing the machine due to problems, replacing important analytical equipment. Record the maintenance results in the periodic analyzer calibration results sheet.
Understanding the circulation and role of antinuclear antibodies in autoimmune pathogenesis, thereby understanding the diagnostic and prognostic value of these antibodies is very important in clinical practice and research in allergy and clinical immunology .

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