Each state has different requirements to apply to a CLS program after you have fulfilled the course requirements. After your receive your BS, you apply to a 1 year internship (clinical program) which will allow to sit for the California state exam. You would need to check the specific state of interest to see their requirements:
Many schools have Majors with a CLS emphasis, however; you can major in any field as long as you fulfill the course requirements for the internship.
Clinical Laboratory Scientist (CLS)
Licensure as a CLS in California requires a Bachelor’s degree with required coursework to qualify for a CLS Trainee license and entry into a training internship program. The internship is generally one year and includes practical laboratory training in all specialty areas of a cooperating medical laboratory as well as didactic training. After training the candidate must pass a comprehensive written exam* to obtain a California CLS License. Many schools also qualify their students to sit for one or more of the national certifying exams which are used as a benchmark in states without licensing laws. Once licensed, renewal will require 24 Continuing Education units per two year licensing cycle.
Required Coursework for CLS
Required Coursework Includes
18 semester or equivalent quarter hours of Biological Science
Required Courses: Medical Microbiology, Hematology and Immunology
Recommended Courses: Parasitology, Virology, Mycology
16 semester or equivalent quarter hours in Chemistry
Required Courses: Analytical Chemistry, (Quantitative Analysis) and Biochemistry
Recommended Courses: Clinical Chemistry
3 semester or equivalent quarter hours in Physics
Including instruction in Principles of Light and Electricity
Helpful Websites: http://www.camlt.org/laboratory-profession#licensing-for-cls
http://www.cdph.ca.gov/programs/lfs/Pages/TrainingPrograms.aspx