044
Test #
Mixed Connective Disease Panel (includes ANA, Sm, RNP70, Jo-1, Scl-70)
CPT Code(s) #
86038, 86039, 86255, 86235 x4
If Profile, Includes Tests:
N/A
Disease Name:
Systemic Connective Tissue Disease
Type of Study:
Serum Studies
Methodology:
Indirect Immunofluorescence and ELISA
Substrate:
HEp2/ELISA plate
Reference Range:
ANA (Titer)
• Negative <40
Sm (Units)
• Negative <20
• Weak Positive 20-39
• Moderate Positive 40-80
• Strong Positive >80
RNP (Units)
• Negative <20
• Weak Positive 20-39
• Moderate Positive 40-80
• Strong Positive >80
Jo-1 (Units)
• Negative <20
• Weak Positive 20-39
• Moderate Positive 40-80
• Strong Positive >80
Scl-70 (Units)
• Negative <20
• Weak Positive 20-39
• Moderate Positive 40-80
• Strong Positive >80
Units:
ANA:Titer, Sm,RNP,Jo-1,SCL-70:Units
Schedule:
Assay performed once per week. Report availability is within one week from the time of specimen receipt.
Specimen Requirements:
Collect 5-10 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into red capped tube provided with Beutner Laboratories collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.
Sample Stability:
Stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable refrigerated (2-8ºC) up to five days and frozen (-20ºC or lower) up to one year.
Clinical Relevance:
Mixed Connective Tissue Disease (MCTD) is a rare autoimmune disease, with mixed clinical features with Polymyositis (PM), Systemic Sclerosis (SSc), Systemic Lupus Erythematosus (SLE), and Rheumatoid Arthritis (RA) along with the presence of high titers of anti-ribonucleoprotein (RNP) antibodies. The most common clinical manifestations of mixed connective disease are Raynaud's phenomenon, arthralgias, swollen joints, esophageal dysfunction and muscle weakness. The disease can be serious with the development of pulmonary, renal, cardiovascular, gastrointestinal and central nervous system manifestations.
Serologic findings include a high ANA titer, often with a speckled pattern, and antibodies directed against a specific ribonuclease-sensitive extractable nuclear antigen, U1RNP. U1RNP antibodies are present in >80% of patients with MCTD. Antibodies to other nuclear antigens have been found in MCTD. Antibodies to dsDNA and Sm are infrequent in patients with MCTD, these are found in 0-8% of patients with MCTD. Anti-Ro antibodies are positive in 13%, Scl-70 and Jo-1 in 7% of patients. Up to 70% of patients will have a positive rheumatoid factor.
Select references:
1. Ortega-Hernandez OD, Shoenfeld Y. Mixed connective tissue disease: an overview of clinical manifestations, diagnosis and treatment. Best Pract Res Clin Rheumatol. 2012 Feb;26(1):61-72
2. Zampieri S, Ghirardello A, Iaccarino L, Tarricone E, Gambari PF, Doria A. Anti-Jo-1 antibodies. Autoimmunity. 2005 Feb;38(1):73-8
3. Ferrara CA, La Rocca G, Ielo G, Libra A, Sambataro G. Towards Early Diagnosis of Mixed Connective Tissue Disease: Updated Perspectives. Immunotargets Ther. 2023 Jul 26;12:79-89.
