Tests and diagnosis
By Mayo Clinic staffYour doctor may suspect mixed connective tissue disease based on your signs and symptoms. A physical exam may reveal signs such as swollen hands and painful, swollen joints.
A blood test can determine whether you have a certain antibody in your blood that indicates mixed connective tissue disease. The presence of this specific antibody — called U1-RNP — can help confirm your doctor's suspicions.
Mixed connective tissue disease usually develops slowly, making it difficult to diagnose. As your symptoms evolve — sometimes over many years — your diagnosis may change. Many people are first diagnosed with lupus and later re-diagnosed with mixed connective tissue disease. Others begin with a diagnosis of undifferentiated connective tissue disease — which means it's unclear which connective tissue disease you have — that later becomes mixed connective tissue disease or, possibly, lupus.
- Bennett RM. Clinical manifestations of mixed connective tissue disease. http://www.uptodate.com/home/index.html. Accessed Dec. 15, 2009.
- Mixed connective tissue disease (MCTD). The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec04/ch032/ch032c.html. Accessed Dec. 25, 2009.
- Hoffman RW, et al. Immune pathogenesis of mixed connective tissue disease: A short analytical review. Clinical Immunology. 2008;128:8.
- Bennett RM. Definition and diagnosis of mixed connective tissue disease. http://www.uptodate.com/home/index.html. Accessed Dec. 15, 2009.

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