What do you need to do to become clinical laboratory scientist?

Do you mean a Clinical Laboratory Technician, the guy who runs your blood test in the hospital laboratory, or processes your throat culture? You would need to take a college level course in laboratory medicine, and then you would apply for ASCP certification. Ask the lab manager at your local hospital for the names of good schools near you, and he/she can give you some guidance where you need to go and what you need to do to get your certification. There USED to be a single certification of MT, Medical Technologist, but the ASCP (American Society of Clinical Pathologists) is more like a union than a certifying body, and they have pretty well seized control of the field over the last 40 years so that if you aren't MT ASCP certified, then you can't work in the laboratory. A shame; they threw away a LOT of talent by doing that. They have also come out with a lot of sub-specialties where you have to get individual certification in each department of the laboratory. Again the ASCP union establishing their turf.