| Evaluation/Test | Frequency | Abnormal finding | Management |
| Genetic (diagnostic) testing | Initial evaluation only to establish diagnosis | Expanded CTG repeat (DM1) or CCTG repeat (DM2) | Genetic counseling for individuals and families |
| Cardiac evaluation: ECG, echocardiogram, Holter monitoring | ECG at baseline and then annually; 24-hour ambulatory ECG monitoring if arrhythmias suspected clinically but not detected on standard ECG; echocardiography if symptoms or signs of myocardial dysfunction are present | Cardiac conduction abnormalities (very common in DM1 and variably present in DM2); structural heart abnormalities | Cardiology consultation and follow-up; may require advanced electrophysiological testing and possibly pacemaker or implantable cardioverter-defibrillator |
| Ophthalmologic examination | Baseline and then every two years | Iridescent posterior subcapsular cataract | May require cataract extraction |
| Forced vital capacity | Baseline and annually | Downward trending | Pulmonary medicine consultation |
| Polysomnographic evaluation | Indicated for evaluation of sleep complaints | Obstructive sleep apnea | Consult and follow-up with pulmonary medicine; consider NIPPV |
| Swallowing assessment: Modified barium swallow | Baseline (if symptomatic dysphagia) and annually or as needed | Oropharyngeal dysphagia | Assessment and follow-up by speech language pathologist and nutritionist |
| Neuropsychologic evaluation for patients with congenital and childhood-onset DM1 | Baseline and as needed thereafter | Learning disabilities; autism spectrum disorder; psychiatric symptoms | Psychiatric/psychologic consultation for specific diagnosis and management of target symptoms; special education; social support; vocational skills training |
| Fasting blood glucose and hemoglobin A1C | Baseline and then annually | Glucose intolerance or frank diabetes | Treatment of diabetes if present |
| Thyroid stimulating hormone | Initial evaluation and every two to three years | Elevated | Endocrinology consultation for treatment of hypothyroidism if detected |
| Creatine kinase* | Initial evaluation | Mild rise | Expected; no action needed |
| Electromyography* | Initial evaluation | Myotonia | Expected; no action needed |
