Synonym

• ANA
• ANA Panel
• FANA
• Fluorescent antinuclear antibody

Tubes

• Red top tube
• 5 mL of venous blood

Handling and other instructions:

• Maintain at room temperature
• Reject the specimen if any of the following is present:
• Gross bacterial contamination
• Hemolysis
• Icterus
• Lipemia

Info

Antinuclear antibodies are a group of antibodies against cellular nuclear antigens like DNA, RNA, nucleoprotein, histones and other nuclear components.

Clinical

Antinuclear antibodies are used to:

• Provide support to the diagnosis of connective tissue disease when there is clinical suspicion
• Screen for connective tissue diseases especially
• Monitor the effectiveness of immunosuppressive therapy for SLE

Additional information:

• The presence of ANA is not specific for any one type of connective tissue disease
• SLE (Systemic Lupus Erythematosus) About 96-99% of SLE cases show positive ANA titers
• Lack of ANA almost rules out SLE; but 1-4% may lack antinuclear antibodies
• 3-4% of the population who have no apparent disease of any kind will have positive antinuclear antibodies; the test must be interpreted in the context of clinical symptoms

Discussion of diagnostic criteria for SLE:

The ANA test is often ordered in patient&'s with non-specific symptoms with consideration of SLE being the underlying condition. SLE symptoms may come and go and a complete review of the medical history is required.

A positive ANA test is one of 11 items on a list of criteria which may be present in patients with SLE. 4 of the 11 items are required to make the diagnosis, 3 of the 11 is suggestive of the diagnosis of SLE. The symptoms do not all need to be present at a single time period.

American College of Rheumatology Criteria (list of 11 items):

1. Malar rash (cheeks)
2. Discoid Rash (anywhere on body)
3. Photosensitivity
4. Oral Ulcers
5. Arthritis (Nonerosive; 2 or more joints)
6. Serositis: Pleuritis or pericarditis
7. Renal Disorder (proteinuria, casts in urine)
8. Neurologic symptoms (Seizures and/or psychosis)
9. Hematologic [Hemolytic anemia or leukopenia (white blood count below 4,000 cells per cubic millimeter) or lymphopenia (less than 1,500 lymphocytes per cubic millimeter) or thrombocytopenia (less than 100,000 platelets per cubic millimeter)]
10. Positive antinuclear antibody (>1:40)
11. Immunologic disorder (positive anti-dsDNA, anti-Sm test, antiphospholipid antibody, anticardiolipin antibody, or false positive syphilis test (VDRL)]

Nl Result

Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.

Titer of 1:40 or less

Results may also be reported as negative or positive (will usually be reported negative if titer is = 1:40).

High Result

ANA titers are often positive in the following conditions:

• Connective tissue diseases:
• Systemic lupus erythematosus (SLE)
• Drug-induced lupus like syndrome
• Mixed Connective Tissue Disease (MCTD)
• Sjogren's syndrome
• Scleroderma
• CREST syndrome
• Polymyositis-dermatomyositis
• Progressive systemic sclerosis
• Rheumatoid arthritis
• Felty's syndrome
• Raynaud's syndrom
• Other conditions:
• Patients over 65 years of age
• Cirrhosis (Hepatic/biliary)
• Hepatitis
• Infectious mononucleosis
• Leukemia
• Myasthenia gravis
• Renal failure (Chronic)
• Thyroiditis (Autoimmune)

Drug Induced false positive ANA may be due to:

• Carbamazepine
• Chlorpromazine
• Ethosuximide
• Griseofulvin
• Heavy metals
• Hydralazine
• Iodides
• Isoniazid
• Mephenytoin
• Methyldopa
• Oral contraceptives
• P-aminosalicylic acid
• Penicillin
• Phenylbutazone
• Phenytoin
• Primidone
• Procainamide
• Propylthiouracil
• Quinidine
• Sulfonamides
• Tetracyclines
• Thiazide diuretics
• Trimethadione

Low Result

No clinical significance to a low result.

• A negative result does not completely rule out SLE
• False negative results may be seen with the use of steroids or other immunosuppressants

References

• Afman IE et Antinuclear antibody testing in obstetric patients. S Afr Med J 2003: 93:932-937
• Lab tests online. ANA [Homepage on internet] ©2001-2006 [updated 2004 Dec 13;cited 2006 August 2] Available from http://labtestsonline.org/understanding/analytes/ana/test.html
• Laboratory Corporation of America. Antinuclear Antibodies (ANA) With Reflex to Multiple Confirmatory Tests [Homepage on internet] c2003 [updated 2006 Jun 8;cited 2006 August 2] Available from http://www.labcorp.com/datasets/labcorp/html/chapter/mono/nf10004770.htm
• MedlinePlus: Medical Encyclopedia. Antinuclear antibody panel [Homepage on internet] c2005 [updated 2006 May 30;cited 2006 Jul 14] Available from http://www.nlm.nih.gov/medlineplus/ency/article/003535.htm
• Nissl J,Terra RP. BC HealthGuide.Antinuclear Antibodies (ANA) [Homepage on internet] c1995-2006 [updated 2004 Aug 27;cited 2006 Jul 14] Available from http://www.bchealthguide.org/kbase/topic/medtest/hw2297/descrip.htm
• Nordenson NJ. HealthAtoZ. Antinuclear antibody test [Homepage on internet] c1999-2006 [updated 2002 Dec;cited 2006 Jul 14] Available from http://www.healthatoz.com/healthatoz/Atoz/ency/antinuclear_antibody_test.jsp
• Tan, E.M., et. al. The 1982 Revised Criteria for the Classification of SLE. Arth Rheum 25: 1271-1277
• www.medicalcriteria.com/criteria/sle.htm
• WebMD.Antinuclear Antibodies (ANA)[Homepage on internet]c1995-2006 [updated 2004 Jul 12;cited 2006 Jul 14] Available from http://www.webmd.com/hw/lab_tests/hw2297.asp