From the Guidelines
Laboratory Tests for MCTD Monitoring
Laboratory tests should not be ordered yearly as a blanket approach to monitor Mixed Connective Tissue Disease (MCTD), as the frequency of testing should be tailored to the individual patient's disease course and risk factors 1.
Risk-Based Approach
A risk-based approach is suggested, where patients with MCTD and prominent features of systemic sclerosis (SSc) or idiopathic inflammatory myopathy (IIM) may benefit from more frequent monitoring, such as every 6 months, while those without these features may require less frequent monitoring, such as annually 1.
Pulmonary Function Tests (PFTs)
Pulmonary function tests (PFTs), including spirometry and diffusing capacity for carbon monoxide (DLCO), are recommended for monitoring MCTD patients, with the frequency of testing depending on the patient's disease course and risk factors 1.
High-Resolution Computed Tomography (HRCT)
High-resolution computed tomography (HRCT) chest is suggested when clinically indicated, such as when there are changes in symptoms or PFT results, or when assessing treatment response 1.
Ambulatory Desaturation Monitoring
Ambulatory desaturation monitoring is also suggested, with a frequency of every 3 to 12 months, to inform the need for supplemental oxygen 1.
Individualized Approach
Ultimately, the frequency of laboratory tests for MCTD monitoring should be individualized based on the patient's specific disease characteristics, risk factors, and clinical course, rather than a one-size-fits-all approach 1.
From the Research
Laboratory Tests for MCTD
The decision to order laboratory tests for Mixed Connective Tissue Disease (MCTD) should be based on the clinical setting and the patient's history and physical examination 2. The following points should be considered:
- Laboratory tests can aid in the differential diagnosis of connective tissue diseases, but the choice of tests should be determined by the clinical setting 2.
- A complete history, thorough physical examination, and knowledge of the course of the disease are essential for making a proper rheumatological diagnosis 3.
- Laboratory tests, such as hemogram, acute phase reactants, and immune factors, can be useful in diagnosing connective tissue diseases, but are relatively non-specific 3.
Monitoring MCTD
There is no clear evidence to support the need for yearly laboratory tests to monitor MCTD. However:
- Long-term follow-up is necessary to monitor disease activity and progression 4.
- Disease activity and remission can be assessed using measures such as the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and the European League Against Rheumatism scleroderma trials and research (EUSTAR) activity index 5.
- Naifold capillaroscopy (NFC) can be a useful non-invasive test for evaluating capillary abnormalities in MCTD patients and may correlate with organ involvement 6.
Disease Activity and Remission
The following points should be considered when monitoring disease activity and remission in MCTD:
- Disease conversion to another defined rheumatic condition can occur in a subset of patients 5.
- Remission is not frequent, but the disease can run a milder course than systemic lupus erythematosus and systemic sclerosis 5.
- Predictors of remission include percentage of predicted higher forced vital capacity 5.