Mixed Connective Tissue Disease Panel (RNP Antibody and ANA with Reflex)

Test Code

19875

CPT Codes
86038, 86235

Includes

ANA Screen, IFA, with Reflex to Titer and Pattern
RNP Antibody

If ANA Screen, IFA is positive, then ANA Titer and Pattern will be performed at an additional charge (CPT code(s): 86039).

Preferred Specimen

2 mL serum

Minimum Volume

1 mL

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 4 days
Refrigerated: 7 days
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis • Grossly lipemic • Grossly icteric • Microbial contamination may interfere

Methodology
Immunoassay (IA) • Immunofluorescence Assay (IFA)

Setup Schedule

See individual assays

Clinical Significance

This panel can be helpful in the diagnosis of individuals with clinical suspicion of mixed connective tissue disease (MCTD). All specimens are tested for antinuclear antibodies (ANAs) with an immunofluorescence assay (IFA), performed on human epithelial type 2 (HEp-2) cells; and RNP antibodies with a multiplex immunoassay. For specimens with positive ANA IFA results, reflex testing for ANA titer and pattern is performed.

The laboratory evaluation for individuals with clinical suspicion of autoimmune diseases often begins with an ANA screen. The classic ANA IFA on HEp-2 cells is considered by the American College of Rheumatology (ACR) as the current gold standard because of its overall high sensitivity for several autoimmune diseases [1]. Knowing the ANA titer and fluorescent staining pattern can be helpful in interpreting positive results [2]. The first indication of MCTD is often a high ANA titer (>1:1000), which occurs in 94% to 97% of patients with MCTD [3]. The presence of RNP antibodies is considered the serologic hall mark of MCTD and required by diagnostic criteria [3].

Individuals with negative results on the ANA IFA usually also have negative results on specific autoantibodies. Therefore, subserology testing is not recommended for individuals without positive ANA IFA results and clinical suspicion of relevant autoimmune disease [4]. However, Jo-1 antibody may be detected in ANA IFA-negative patients with some types of myositis, and SSA antibody may be detected in some ANA IFA-negative patients with lupus or Sjogren syndrome [4].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Methodology of testing for antinuclear antibodies (position statement). 2009. American College of Rheumatology. Updated December 2019. Accessed May 15, 2023. https://assets.contentstack.io/v3/assets/bltee37abb6b278ab2c/blta48818378bc89445/acr-position-statement-methodology-testing-antinuclear-antibodies.pdf
2. Tozzoli R, et al. Am J Clin Pathol. 2002;117(2):316-324.
3. Cappelli S, et al. Semin Arthritis Rheum. 2012;41(4):589-598.
4. Yazdany J, et al. Arthritis Care Res (Hoboken). 2013;65(3):329-339.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.