Antinuclear Antibody (ANA)Test: Introduction, Principle, Procedure, Result Interpretation, Clinical Significance, and Keynotes

Introduction of Antinuclear Antibody (ANA)Test

The antinuclear antibody (ANA)test is a type of blood test in which serum tested for autoantibodies ( SLE) directed against native deoxyribonucleic acid and other nuclear constituents are produced. It involves a variety of tissues and is associated with a wide range of antibodies in circulation. Characteristics of the disease are antibodies against native DNA, nucleoprotein, denatured DNA,  and other affects a wide range of tissues. The organs affected are, in decreasing incidence, joints, skin, kidneys, central nervous system, heart, and lungs.

Principle of Antinuclear Antibody (ANA)Test

Latex particles are bound with native DNA by means of an intermediary albumin matrix. These coated latex particles combine with any antibodies to n- DNA in serum to give a visible agglutination.

Test requirements for Antinuclear Antibody Test

1. Serum (non- hemolyzed)
2. Diagnostic kit:  It contains the following materials-
3. Anti-n DNA latex reagent
4. Positive control
5. Negative control
6. Plastic slide/Agglutination slide or tile
7. Dropper pipette/Micropipette
8. Extra we need-Tube a rack
9. Waste disposing bin
10. Gloves

Procedure of ANA Test

1. Bring all reagents to room temperature and mix gently before use.
2. Place 1/1 drop of the test sample (serum), Positive Control (red cap), and Negative Control (green cap) in separate divisions (cells) of the same slide respectively as shown above image.
3. Anti-n DNA latex reagent/SLE latex reagent to each cell.
4. Mix with the flat end of the pipette/mixer and spread fluid evenly over each cell.
5. Tilt the slide back and forth slowly for 2 minutes.
6. Observe for agglutination.

Result and Interpretation of Antinuclear Antibody (ANA)Test

Agglutination:Positive

No agglutination: Negative

Test (1): Positive due to agglutination

Positive Control (2): Positive

Negative Control (3): Negative

Clinical Significance of the ANA Test

1. ANA test is useful when you have conditions like joint or muscle pain, stiffness or swelling, tiredness, recurring or persistent fever, a red rash on the cheeks and bridge, numbness and tingling in your hands or feet, and hair loss.
2. ANA test is positive in various health conditions like systemic lupus erythematosus (SLE), Sjogren’s syndrome, scleroderma, rheumatoid arthritis, polymyositis, juvenile chronic arthritis, dermatomyositis, polyarteritis nodosa, and autoimmune hepatitis.

Keynotes on ANA Test

1. The frequency of  SLE  is high in women (approximately 3-4 times more frequent in men).
2. Reagent positive and negative control are stable at 2-8°C.
3. Bring reagent, positive and negative control to room temperature (25°C-/+ 5°C) prior to use.
4. False positive ANA test may occur due to the following conditions- a woman age 65 or older, mononucleosis or tuberculosis, and taking blood pressure or anti-seizure drugs.

Further Readings

1. http://www.vitroscience.cl/pdf/stanbio/RAPET_sLE.pdf
2. http://www.rapidtest.com/index.php?i=SLE-(Systemic-Lupus-Erythematosus)&id=577&cat=98
3. https://www.thermofisher.com/order/catalog/product/LAT701050#/LAT701050
4. https://labtestsonline.org/tests/antinuclear-antibody-ana
5. https://www.medicinenet.com/antinuclear_antibody/article.htm