Types of Diagnostic Testing For MD
MD cannot be diagnosed with symptoms alone. This is because many of the symptoms exhibited by patients with MD are generalizable to many other neurological disorders. To truly pinpoint the cause of symptoms that an individual is experiencing, testing must be done. There are many different types of testing that can be performed.
Bloodwork
The muscle damage caused by some types of MD means that the level of creatine kinase in the blood will often be higher than normal. A blood sample may also be used for genetic testing, and this can sometimes identify the cause of muscle problems without the need for a muscle biopsy.
Genetic Testing
Genetic testing can be done via bloodwork or other means of bodily fluid/tissue. DNA is extracted from a blood, saliva, or tissue sample of a patient and compared to a DNA sample of an individual who is carrying the faulty gene. If the DNA sequencing matches, this type of testing can confirm that a patient does have MD.
Muscle Biopsies
Your provider will only need to remove a small piece of tissue from the designated muscle. Your doctor takes the tissue sample by inserting a biopsy needle into your muscle. If a larger sample is required, your healthcare provider may make an incision in your skin and remove a larger section of muscle. This muscle can then be used for physical evaluation of tissue. When assessing the tissue, doctors examine the sample for hallmarks of MD. If hallmarks are found, the sample is sent for genetic testing to confirm.
Magnetic Resonance Imaging (MRI)
This type of testing is not a confirmatory test. It simply scans the brain, spinal cord, and muscles to look for damage. In case damage is found, further testing may be done to determine the cause of the damage.
Electromyog-raphy (EMG)
To perform this test, the doctor inserts a tiny needle—a conductor for electrical current called an electrode—through the skin and into the muscle. This allows your doctor to measure the amount of electricity generated by muscle cells when they become activated by a nerve impulse. If muscle reaction is low, more testing may be needed to confirm the reason for low impulse.
Nerve Conduction Testing
This type of testing is quite similar to EMG. During a nerve conduction test, a doctor stimulates the nerve and measures the time it takes to respond. Several places along the nerve are tested, and the area where the response takes too long is likely to be the place where the nerve is compressed. The difference between EMG and nerve conduction testing is that EMG measures the muscle response to nerve stimulation, while nerve conduction testing measures the nerve stimulation and impulse itself.
Electrocardio-gram (ECG)
Muscular dystrophy causes the atrophy of all muscles, including the heart. An ECG measures the functionality of the heart. If issues are detected with the heart, more testing will be needed to confirm that MD is the source of the problems. This test is not a confirmatory test but rather, it is an indicator that more testing is needed.