The tests that are indicated when mitochoncrial disease is suspected are listed below [and are all from the web page, Getting A Diagnosis, from the United Mitochoncrial Disease Foundation (UMDF) website [these tests would also be indicated in a pediatric patient with suspected metabolic diseases]:
Mitochondrial diseases are difficult to diagnose. Referral to an appropriate research center is critical. If experienced physicians are involved, however, diagnoses can be made through a combination of clinical observations, laboratory evaluation, cerebral imaging, and muscle biopsies. Despite these advances, many cases do not receive a specific diagnosis.
Most hospitals do not have a metabolic laboratory and therefore can run only the most basic tests. However, most hospitals will send specimens to any laboratory in the country. Not all laboratory tests are required for all patients, and your physician may decide that some of these tests are not necessary. In addition, a single blood or urine lab test with normal results does not rule out a mitochondrial disease. This is true for organic acids, lactic acid, carnitine analysis and amino acid analysis. Even muscle biopsies are not 100% accurate.
Metabolic Screening in Blood and Urine (all patients)
Basic chemistries Quantitative plasma amino acids Plasma acylcarnitine analysis Complete blood count Liver enzymes & ammonia Quantitative urine organic acids Blood lactate, pyruvate, L:P ratio Creatinine kinase (CPK)
Characterize Systemic Involvement (all patients)
Echocardiogram Brain MRI Audiology testing Ophthalmologic exam Electrocardiogram (EKG)
Metabolic Screening in Spinal Fluid (patients with neurological symptoms)
Lactate & pyruvate Quantitative amino acids Routine studies including cell count, glucose and protein measurement
Clinical Neurogenetics Evaluation (patients with developmental delays)
Karyotype Fragile X test Genetics consultation Child neurology consultation