Antinuclear antibodies are antibodies the body produces against nuclear components
of its own cells. This results in the development of an autoimmune disease.
The antinuclear antibody (ANA) test is commonly used to rule out systemic lupus
erythematosus (SLE) because 95% to 99% of SLE patients have positive ANA
titers. A titer is the most dilute serum in which the ANA is detected. The ANA test
uses an indirect immunofluorescent procedure, which results in several staining
patterns: homogeneous, nucleolar, peripheral, and speckled patterns. These patterns
assist in diagnosing the specific disease process affecting the individual.
Normal Values
Negative at 1:8 dilution
Possible Meanings of Abnormal Values
Positive
Bacterial endocarditis
Chronic autoimmune hepatitis
Cirrhosis
Connective tissue diseases
Dermatomyositis
Discoid lupus erythematosus
Drug-induced lupus
Infectious mononucleosis
Leukemia
Malignancy, especially lymphoma
Mixed connective tissue disease
Myasthenia gravis
Polymyositis
Raynaud’s syndrome
Rheumatoid arthritis
Scleroderma
Sjögren’s syndrome
Systemic lupus erythematosus
Tuberculosis
Contributing Factors to Abnormal Values
• Hemolysis of the blood sample may alter test results.
• Drugs that may cause a false-positive result due to a drug-induced syndrome similar
to SLE: acetazolamide, carbidopa, chlorothiazide, chlorpromazine, clofibrate, ethosuximide,
gold salts, griseofulvin, hydralazine, isoniazid, lithium, methyldopa, oral
contraceptives, penicillin, phenylbutazone, phenytoin, primidone, procainamide,
propylthiouracil, quinidine, reserpine, streptomycin, sulfonamides, tetracyclines, thiazide
diuretics.
• Drugs that may cause a false-negative result: steroids.
Interventions/Implications
Pretest
• Explain to the patient the purpose of the test and the need for a blood sample to be drawn.
• No fasting is required before the test.
Procedure
• A 7-mL blood sample is drawn in a red-top collection tube.
• Gloves are worn throughout the procedure.
Posttest
• Apply pressure at venipuncture site. Apply dressing, periodically assessing for continued
bleeding.
• Label the specimen and transport it to the laboratory.
• Report abnormal findings to the primary care provider.
Clinical alert
• Positive ANA results can occur in people with no known autoimmune disease.
• Risk of infection at venipuncture site due to immunocompromised state. Teach
patient to notify health-care provider if drainage, redness, warmth, edema, or
pain at the site or fever occur.
تعليقات
إرسال تعليق