Although fresh tissue is the best material to submit for electron microscopy, you can also use formalin fixed tissue as well as paraffin embedded tissue. Autopsy material can be submitted for electron microscopy. Organelle preservation is often compromised. However, neurosecretory granules, tonofibrils, desmosomes, viruses and immune complex deposits in the kidney are often sufficiently preserved for diagnostic purposes. This is an excellent source of material.
Techniques are available for separating blood from cells.
The cells are pelleted, fixed in a routine EM fixative and then processed.