Test ID: Z0946
CPT code: 86235
LOINC: 53022-0
Specimen Type: Red or SST tube
Frequency: 14 – 21 days
Instructions: 1 mL Serum from Red or SST, Refrigerated, Separate within one hour. Min 0.5 mL.
Text: Anti-U1 RNP antibodies typically appear in both SLE and MCTD. In MCTD, the presence of U1 RNP is required for diagnosis, whereas anti-RNP antibodies occur in only 30-40% of SLE. MCTD is typified by the high-titer RNP antibody activity in isolation; anti-RNP antibody activity in SLE commonly accompanies anti-Sm antibodies.
Methodology: Enzyme-linked immunosorbent assay (ELISA)