Forgot to mention that the cost of an EMG is about $1500 and a muscle biopsy is about twice that (even more if it's done with general anesthesia or IV sedation) plus the pathology fee. You can see which is the better money-maker for the hospitals. I'm getting cynical in my old age :-)
Hi,
In support of what Jan said about biopsy; The reason muscle biopsy is rarely used outside of research is that an MRI can reveal most muscle abnormalities. Second, as she said they are most often inconclusive in CLCN1 defects. On the other hand they are more useful in Sodium Channel diseases (SCN4a), but here again an MRI is just as useful as a biopsy.
I am sorry but I must add more complexity to the picture. A nerve EMG makes a positive finding in 90% of Ion Channelopathies. I am among the 10% without electrical myotonia. Some who do not exhibit electrical myotonia on initial testing may still have it inferred from a test that includes muscle that is stressed by an exercise routine and cold. So if one is not prepared to test for the rarest occurance then one is not prepared to do a complete test.
If you feel in the least frustrated or insecure about your doctors, may I suggest that you make arrangements to be seen at the Neuromuscular Clinic at the University of Rochester, they are among the top three clinics in the US. Prof. Robert Griggs M.D. will respond to email sent directly to him. His address is to a staff member:
Patricia_Hopkins@urmc.rochester.edu
Good Luck, Joe