Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)

Norm of Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)

Negative or <20 units.
20–49 units.
≥50 units.


Usage of Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)

Assists in differentiating the type of autoimmune disease occurring. Highest titers (≥1:10,000) are suggestive of mixed connective tissue disease such as Raynaud's phenomenon. Positive in cytomegalovirus infection, neonatal lupus erythematosus, Sjögren's syndrome, systemic lupus erythematosus.


Description of Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)

An antinuclear antibody present in over 94% of mixed connective tissue autoimmune disease detected by an immunofluorescent procedure. Immunofluorescence results in characteristic staining patterns that help differentiate the type of connective tissue disease occurring. Anti-RNP antibodies are associated with a speckled pattern and occur in almost all clients with mixed connective tissue syndrome and about one fourth of clients with scleroderma and discoid and systemic lupus erythematosus. High titers are usually accompanied by clinical symptoms of mixed connective tissue disease. A positive test is specific for mixed connective tissue disease when results of other autoantibody testing are negative.


Professional Considerations of Anti-RNP Test (Antiribonucleoprotein Test, Extractable Nuclear Antigen)

Consent form NOT required.

  1. Tube: Red topped, red/gray topped, or gold topped.
  2. See Client and Family Teaching.



  1. Draw a 4-mL blood sample.


Postprocedure Care

  1. Transport the specimen to the laboratory for immediate spinning.


Client and Family Teaching

  1. Fast for 8 hours before sampling.
  2. Results may not be available for several days if testing is not performed on site.


Factors That Affect Results

  1. Reject hemolyzed, lipemic, or contaminated specimens.
  2. False-negative results may be caused by drug therapy with corticosteroids.
  3. Drugs that may cause false-positive results because of a drug-induced syndrome resembling systemic lupus erythematosus (SLE) include acetazolamide, aminosalicylic acid, carbidopa, chlorothiazide, chlorpromazine, clofibrate, diphenylhydantoin, ethosuximide, gold salts, griseofulvin microsize, griseofulvin ultramicrosize, hydralazine, hydrochloride, hydroxytryptophan, isoniazid, mephenytoin, methyldopa, methyldopate hydrochloride, methyl-thiouracil, methysergide maleate, oral contraceptives, penicillin, phenylbutazone, phenytoin, primidone, procainamide hydrochloride, propylthiouracil, quinidine gluconate, quinidine polygalacturonate, quinidine sulfate, reserpine, streptomycin sulfate, sulfadimethoxine, sulfonamides, tetracyclines, thiouracil, and trimethadione.


Other Data

  1. Titer is determined by counterimmunoelectrophoresis (CIE).