Antinuclear Antibodies, HEp-2 Substrate, IgG, Serum

Casandra

Casandra Test Code MC18702Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID NAIFACPT Code 86039

Antinuclear Antibodies, HEp-2 Substrate, IgG, Serum

Clinical Use

Use

The test is used for the evaluation of patients suspected of having systemic autoimmune rheumatic diseases, such as systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), Sjogren syndrome, systemic sclerosis (SSc), and other autoimmune diseases like autoimmune liver diseases. These diseases are often associated with antinuclear antibodies (ANAs), traditionally detected using the HEp-2 cell line substrate by indirect immunofluorescence. ANAs may target antigens not only in nuclear regions but also in cytoplasmic and mitotic regions, which are clinically relevant. The test is an initial screen for ANA-associated rheumatic diseases but requires confirmation with more specific tests due to limited diagnostic specificity.

Special Instructions

Positive results require confirmation using additional ANA-associated antibody tests, especially since the anticellular antibody test lacks diagnostic specificity. Clinical context and patient's demographics should guide test interpretation, as some patterns like the centromere pattern are indicative of specific disease types, such as limited diffuse SSc.

Limitations

The test's lack of specificity can be a challenge, as it may result in positive findings in patients without clinical evidence of systemic autoimmune rheumatic disease, sometimes preceding clinical manifestations. Variability in test performance can occur due to differences in reagent and kit design across laboratories. Positive results should be confirmed with additional specific tests targeting extractable nuclear antigens or based on clinical presentation.

Test Details

FDA Approved