I am a Medical Laboratory Scientist. I work in the lab performing all types of testing on blood and body fluids that the physician, PA, or NP order. This ranges from Hematology, Coagulation, Chemistry, Urinalysis, Microbiology, Immunology, Toxicology, Molecular (DNA sequencing), Virology, and Flow Cytometry (CD4/CD8 counts and detecting different cellular markers that are specific to tumor cells in ALL, AML, CML, CLL, etc). I can also work in a blood bank if I wanted, performing blood types, cross-matching compatible units and discovering and identifying any antibodies a patient might have developed if they receive frequent blood transfusions.
As part of my job, I work up in the OR for open heart surgeries. There I run blood gasses while the heart is stopped and the patient is on bypass, and run ACT's (activated clotting times) to make sure we have them properly anti-coagulated. In fact, I just got called in the middle of last night to go in to work on a heart transplant case. It's really fun to work in the OR for open hearts. I'm always amazed at how far we've come with medicine!
I too have been thinking about heading down the PA track. I am hoping to job shadow some of the PA's in the surgery suites that I know, as well as some that work as generalists in family practices and others that work orthopedics.