A muscle biopsy for mito is not the conclusive test.
Myth
A muscle biopsy is the "gold standard" for diagnosis of mitochondrial disease.
Fact
Although the muscle biopsy is a powerful diagnostic tool, it should not be considered a "gold standard." Examination of a biopsy includes microscopic evaluation, enzyme testing, and genetic testing. Although all U.S. labs that offer muscle biopsy meet strict laboratory guidelines, there is no agreed-upon standard approach for enzyme testing. Furthermore, a muscle biopsy with full analysis costs well over $10,000 and poses both surgical and anesthetic risks. In some patients, the diagnosis can be made based on clinical symptoms and a positive blood test (identifying a genetic mutation) or a combination of clinical findings and other non-invasive testing -- in either case, a muscle biopsy is not necessary.
Finally, since biopsy results usually do not alter the long-term outcome or treatment considerations, some specialists and patients choose to treat without the need for a muscle biopsy.
Myth
A muscle biopsy is a muscle biopsy no matter where and how it is done.
Fact
Muscle removed for biopsy can be tested in many ways. For example, enzyme testing can be done on either ground-up muscle or on mitochondria extracted from muscle. Testing on extracted mitochondria is performed in only a few medical center laboratories and must be performed immediately. This procedure is known as a "fresh biopsy." In an alternative procedure, called a "frozen biopsy," the muscle is quickly cooled and stored at -80 degrees Celsius for testing at an outside facility. The scientific community is currently debating the advantages of testing "fresh vs. frozen" mitochondria. Some evidence indicates that the "fresh biopsy" may be the superior method. Other types of mitochondrial testing of the muscle biopsy may need to be conducted; a limited number of laboratories offer such testing.
http://my.clevelandclinic.org/disor...s_and_facts_about_mitochondrial_diseases.aspx
MA DCF could have followed Justina to Tufts.