Ordering Recommendation

May aid in the workup of suspected rheumatoid arthritis or undifferentiated inflammatory arthritides. The preferred test is Rheumatoid Arthritis Panel (3016634).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Serum separator tube.

Specimen Preparation

Separate serum from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)

Storage/Transport Temperature


Unacceptable Conditions

Contaminated, heat-inactivated, hemolyzed, icteric, or lipemic specimens.


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)


Semi-Quantitative Enzyme-Linked Immunosorbent Assay


Sun, Tue, Thu


1-4 days

Reference Interval

0-19 Units

Interpretive Data

Anti-carbamylated protein (anti-CarP) IgG antibodies are present in about 34-53 percent of patients with RA, have specificities of greater than 90 percent and can occur in RA patients seronegative for both rheumatoid factor and anti-CCP. These autoantibodies may be present in the preclinical phase of disease, are associated with future RA development, and may predict radiographic joint destruction. Patients with weak positive results should be monitored and testing repeated.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Analyte Specific Reagent (ASR)


Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
3003993 Carbamylated Protein Antibody, IgG
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Carbamylated protein IgG
  • CarP IgG
Carbamylated Protein (CarP) Antibody, IgG