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Test ID: RIB Ribosome P Antibodies, IgG, Serum

Reporting Name

Ribosome P Ab, IgG, S

Useful For

As an adjunct in the evaluation of patients with lupus erythematosus (LE)


Aids in the differential diagnosis of neuropsychiatric symptoms in patients with LE

Clinical Information

The 80S mammalian ribosome is composed of approximately equal amounts of protein and RNA. The larger 60S subunit contains 3 acidic phosphoproteins, PO, P1, and P2 with molecular masses of 38 kDa, 19 kDa, and 17 kDa, respectively. The major immunoreactive epitope of these 3 autoantigens is found within 22 consecutive amino acids of the carboxy terminus of these 3 highly conserved proteins.


It has been known for some time that sera from some patients with lupus erythematosus (LE) react with ribosomal protein antigens. Studies performed with synthetic peptide antigens revealed that reactivity detected by immunoprecipitation and by immunofluorescence methods in sera from LE patients was directed at the above mentioned epitope. Antibodies to ribosome P proteins are considered highly specific for LE, and have been reported in patients with central nervous system (CNS) involvement and so called "lupus psychosis." The reported frequency of antibodies to ribosome P protein autoantigens in patients with LE is approximately 12%.


Since patients with LE may manifest signs and symptoms of CNS diseases including neuropsychiatric symptoms, the presence of antibodies to ribosome P protein may be useful in the differential diagnosis of such patients. Other causes of CNS symptoms in patients with LE include thrombosis with or without antibodies to phospholipid antigens and iatrogenic effects from treatment with corticosteroid drugs.


A positive result is consistent with the diagnosis of lupus erythematosus, and may indicate the presence of central nervous system involvement.

Testing Algorithm

See Connective Tissue Disease Cascade (CTDC) in Special Instructions.

Report Available

Same day/1 to 3 days

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Bonfa E, Golombek SJ, Kaufman LD, et al: Association between lupus psychosis and anti-ribosomal P protein antibodies. N Engl J Med 1987;317:265-271

2. Bonfa E, Elkon KB: Clinical and serologic associations of the anti-ribosomal P protein antibody. Arthritis Rheum 1986;29:981-985

Method Name

Multiplex Flow Immunoassay

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.35 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

<1.0 U (negative)

≥1.0 U (positive)

Reference values apply to all ages.

Test Classification

This test has been cleared, approved or is exempt by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
RIB Ribosome P Ab, IgG, S 53892-6


Result ID Test Result Name Result LOINC Value
RIB Ribosome P Ab, IgG, S 53892-6
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Demyelinating-Diseases, mml-Neuroimmunology, mml-Pediatric, mml-Spinal-Cord