Using different tests on different sections, they look at the tissue's overall appearance, chemical activities in the tissue, and the presence or absence of critical proteins. The information these tests provide helps determine exactly what disease and what form of it the person has. This analysis can yield information about muscle degeneration and regeneration, fiber type abnormalities, mitochondrial abnormalities, scar tissue, inflammation and other clues to specific disorders. Histochemistry uses stains to detect chemical activities in the cells, including the actions of specific enzymes and metabolic processes. A lab that performs only histology may miss important metabolic abnormalities.
Immunohistochemistry uses antibodies to detect the presence or absence of proteins.
Specific antibodies can also be used to identify the nature of inflammatory cells found in the muscle. The lab may also use electron microscopy to get very high magnification views of the cellular structure, which can confirm structural abnormalities, like the presence of nemaline rods. Finally, a DNA analysis can be performed on a muscle sample to detect a genetic mutation. Although a blood sample is usually adequate for a DNA test, a muscle sample may be needed to test for mitochondrial DNA mutations. Multiple Biopsies Yadollah Harati, a neurologist and director of the Muscle and Nerve Pathology Laboratory at Baylor College of Medicine in Houston, usually takes as many as five separate muscle samples from different regions of the muscle incision.