Information on becoming a Clinical Laboratory Scientist

What is a Clinical Laboratory Scientist (CLS)?

A Clinical Laboratory Scientist (CLS) is a licensed healthcare professional who performs laboratory analyses in all departments of a clinical laboratory, using samples from the human body. The analysis is performed on body fluids such as blood, urine, sputum, stool, and body fluids such as cerebrospinal, peritoneal, pericardial and synovial fluids, as well as other specimens. The CLS provides invaluable information for the prevention, diagnosis, treatment and management of disease, using sophisticated biomedical instruments to generate accurate and reliable test results. A CLS must interpret quality assurance parameters, troubleshoot analytical instruments and develop and modify testing methods. A CLS should be detail-oriented, with good communication skills and the ability to multitask efficiently.

Clinical Laboratory Scientists work in hospitals, private clinical labs and doctors offices, as well as research labs. Other career opportunities include working in specialty laboratories (forensics, fertility or veterinary labs), biotechnology labs, sales and marketing with biomedical supply and pharmaceutical companies, infection control (Public Health) labs. Some individuals with CLS training work with laboratory computer systems or as laboratory inspectors.

What training and licensing is required?

Licensure as a CLS in California requires a license from the California Department of Public Health (CDPH), Laboratory Field Services.

Required coursework: The CLS license requires a Bachelor's degree with required course work to qualify for a CLS Trainee license and entry into a training internship program. Required course work for CLS licensure includes:

  • 18 semester or equivalent quarter hours of biological science
  • 16 semester or equivalent quarter hours in chemistry
  • Required courses in medical microbiology, hematology, immunology, analytical chemistry (quantitative analysis), biochemistry, physics (3 units incl. principles of light and electricity)
  • Recommended courses in parasitology, virology, mycology, clinical chemistry

Note that these are the minimum requirements. Internship programs are highly competitive, and admission usually requires a wealth of laboratory experience, both inside and outside of university classes.

CLS internship program: The internship is one year and includes practical laboratory training as well as didactic training in all specialty areas of a State approved medical laboratory. There are 13 training programs for the CLS Generalist License located throughout the State of California. The number of trainee positions varies at each site. Some California training sites pay a stipend. Some charge tuition. There is one program in San Diego County coordinated byUCSD Medical Center and affiliates (contact Barbara Sevilla). UCSD does not pay a stipend, but also has no tuition fee requirement. Contact information for the remainder of the CLS training programs in California can be found here.

Requirements for each internship program are posted on their respective websites, or can be obtained by contacting them directly. Applicants must have completed all state-mandated coursework. Applicants are ranked using a variety of criteria that always include letters of recommendation and GPA. The minimum GPA varies from approximately 2.75 to 3.00 among programs. However, CLS internship training programs are highly competitive, and those students who do get accepted will almost always have higher GPAs than the posted minimum.

Experience in an academic or clinical laboratory is highly recommended (especially clinical). Admission to internship programs is highly competitive, and lab experience will enhance your application. Having additional laboratory classes on your classes will also increase your chances of admission.

California CLS License: After training, the candidate must pass a comprehensive national certifying examination to obtain a California CLS License. Once licensed, renewal will require 12 Continuing Education units per year.

The SDSU Microbiology major with CLS emphasis

All the required course work for a CLS license is currently available at SDSU. With the exception of Chemistry 251, all the necessary courses can also be used towards the requirements for our Microbiology major with CLS emphasis.

Note that completion of the SDSU B.S. degree in Microbiology (with emphasis in CLS):

  • does not include a CLS internship training program
  • does not guarantee admission to a CLS internship training program
  • does not guarantee a California CLS License

Additional information

For more information about our program at SDSU, see the following pages:

For more information about state licensing and internships, see the following pages:



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