Clinical Laboratory Scientists (CLS) -- also known as Medical Laboratory Scientists (MLS) or Medical Technologists (MT) -- are essential healthcare professionals who perform complex diagnostic testing on patient samples. Their work directly informs physician diagnoses, treatment decisions, and patient outcomes. Despite working behind the scenes, clinical laboratory scientists are responsible for generating an estimated 70% of the data used in medical decision-making.

This guide walks you through every step of the process, from choosing a NAACLS-accredited program to passing the ASCP Board of Certification exam, meeting state licensure requirements where applicable, and maintaining your credentials through continuing education. We have also compiled verified data for all 51 states we track so you can compare requirements side by side.

What Does a Clinical Laboratory Scientist Do?

Clinical Laboratory Scientists perform complex medical laboratory tests on blood, body fluids, and tissue samples to help detect, diagnose, and monitor diseases. They analyze test results for accuracy, troubleshoot instruments and methodologies, and report findings to physicians and other healthcare providers. CLS professionals are trained to operate and maintain sophisticated laboratory instruments, including automated analyzers, microscopes, and molecular diagnostic equipment.

The profession goes by several titles, which can be confusing. A Clinical Laboratory Scientist (CLS), Medical Laboratory Scientist (MLS), and Medical Technologist (MT) all refer to the same role. The title used often depends on the state, employer, or certifying body. The ASCP Board of Certification uses the MLS(ASCP) credential, while some states still use the older MT designation.

CLS professionals work across a wide range of laboratory settings, including:

• Hospital laboratories: The most common workplace, performing urgent and routine testing across all departments -- chemistry, hematology, blood bank, microbiology, and urinalysis.
• Reference laboratories: High-volume commercial labs (such as Quest Diagnostics and Labcorp) that process tests from physician offices and clinics nationwide.
• Clinics and physician office labs: Smaller settings where CLS professionals may handle a broader range of duties with less specialization.
• Public health laboratories: State and federal labs that focus on infectious disease surveillance, environmental testing, and outbreak response.
• Research laboratories: Academic and pharmaceutical research settings where CLS professionals contribute to clinical trials and biomedical research.

According to the U.S. Bureau of Labor Statistics, the median annual wage for clinical laboratory technologists and technicians is approximately $60,000--$62,000, with experienced professionals in high-demand areas and specialized roles earning significantly more. The field is experiencing a nationwide workforce shortage, making job prospects strong for qualified candidates.

Step 1: Education Requirements

NAACLS-Accredited Programs

The standard path to becoming a CLS/MLS is earning a bachelor's degree from a program accredited by the National Accrediting Agency for Clinical Laboratory Sciences (NAACLS). NAACLS is the primary accrediting body recognized by both the ASCP Board of Certification and state licensing agencies. Completing a NAACLS-accredited program is typically required for eligibility to sit for national certification exams.

A qualifying MLS/CLS program includes extensive coursework in:

• Clinical chemistry and biochemistry
• Hematology and coagulation
• Clinical microbiology (bacteriology, virology, mycology, parasitology)
• Immunology and serology
• Immunohematology (blood banking and transfusion medicine)
• Urinalysis and body fluids
• Molecular diagnostics
• Laboratory management and quality assurance

Clinical Rotations

NAACLS-accredited programs include extensive clinical rotations -- typically during the final year of the bachelor's program -- where students gain hands-on experience in a hospital laboratory setting. Clinical rotations cover all major laboratory departments and provide the practical skills needed to perform independently after graduation. Most programs require a minimum of one full academic year (approximately 1,000 hours) of supervised clinical training.

There are two common program formats:

• University-based "4+0" programs: Integrated four-year programs where all didactic coursework and clinical rotations are completed within a single degree.
• Hospital-based "3+1" programs: Students complete three years of prerequisite sciences at a university, then apply to a hospital-based clinical training program for the final year.

Step 2: ASCP Board of Certification Exam

The American Society for Clinical Pathology (ASCP) Board of Certification (BOC) administers the most widely recognized national certification exam for clinical laboratory scientists. The MLS(ASCP) credential is the gold standard in the profession and is required or preferred by the vast majority of employers and state licensing agencies.

Key exam facts:

• Credential awarded: MLS(ASCP) -- Medical Laboratory Scientist certified by the ASCP Board of Certification.
• Format: Computer-based exam with approximately 100--110 scored questions covering all major laboratory disciplines.
• Content areas: Blood banking, chemistry, hematology, immunology, microbiology, urinalysis/body fluids, and laboratory operations.
• Testing: Administered at Pearson VUE testing centers year-round.
• Passing score: Scaled scoring; candidates receive a pass/fail result.
• Eligibility: Graduation from a NAACLS-accredited MLS/CLS program (or equivalent education and clinical experience routes recognized by ASCP).

Alternative Certification: AMT

American Medical Technologists (AMT) also offers a national certification for medical technologists: the MT(AMT) credential. AMT certification is accepted by some employers and states, but ASCP certification remains the most widely recognized and is specifically required by many state licensing laws. If you are pursuing state licensure, verify which certifications your state accepts.

State-by-State Clinical Laboratory Scientist Requirements

Not all states regulate clinical laboratory scientists through state licensure. Only about 10 states -- including California, Florida, and New York -- require a state license to practice. In the remaining states, employers typically require ASCP certification even though there is no state licensing mandate. Click any state name to see its complete requirements.

Data sourced from official state licensing board websites and the ASCP Board of Certification. Requirements change frequently -- always verify with your state board before applying.

States That Require Licensure for Clinical Laboratory Scientists

Unlike many healthcare professions where every state requires a license, clinical laboratory science is regulated at the state level in only a small number of states. Approximately 10 states currently require clinical laboratory scientists to hold a state license. These states include California, Florida, New York, and several others that have enacted clinical laboratory personnel licensure laws.

In states without licensure requirements, employers still typically require national certification (usually ASCP) as a condition of employment. Even in non-licensing states, holding ASCP certification is considered the professional standard and is essential for career advancement.

Key differences in licensing states:

• California: Has one of the most rigorous licensure systems, administered by the California Department of Public Health Laboratory Field Services. California requires a specific CLS license and has its own education and exam requirements.
• Florida: Requires licensure through the Florida Department of Health, with specific education and examination requirements for clinical laboratory personnel.
• New York: The New York State Education Department issues clinical laboratory technologist licenses, with specific education and examination requirements.

Continuing Education Requirements

Maintaining your CLS/MLS credentials requires ongoing continuing education (CE). Requirements exist at two levels: national certification maintenance and state licensure renewal (where applicable).

ASCP Certification Maintenance

The ASCP Board of Certification requires certificants to participate in the Credential Maintenance Program (CMP). The CMP operates on a three-year cycle and requires documented continuing education activities to maintain active certification status. Certificants must demonstrate ongoing competence through a combination of CE activities, including professional development, laboratory-related coursework, and other approved educational activities.

State License Continuing Education

States that license clinical laboratory scientists have their own CE requirements for license renewal, which may differ from ASCP's national requirements. Across the 51 states we track, the average CE requirement is 32.9 hours per renewal cycle. Some states accept ASCP-approved CE toward state license renewal; others require state-specific coursework.

Tips for managing CE requirements efficiently:

• Track your CE hours year-round rather than scrambling at renewal time. Many online platforms offer CE tracking tools.
• Professional organizations such as ASCP, the American Society for Clinical Laboratory Science (ASCLS), and the Clinical Laboratory Management Association (CLMA) offer CE opportunities through conferences, webinars, and publications.
• Look for activities that satisfy both ASCP certification maintenance and state licensure renewal requirements simultaneously.
• Many laboratory journals offer CE credits for reading articles and completing assessments -- a convenient way to stay current with clinical advances while earning credit.

Frequently Asked Questions

Sources

The information in this guide is compiled from official sources. We recommend verifying current requirements directly with these organizations before making career or educational decisions:

• American Society for Clinical Pathology (ASCP) -- Board of Certification
• National Accrediting Agency for Clinical Laboratory Sciences (NAACLS) -- Program Directory
• U.S. Bureau of Labor Statistics -- Clinical Laboratory Technologists and Technicians
• American Medical Technologists (AMT)
• American Society for Clinical Laboratory Science (ASCLS)
• Individual state licensing board and health department websites -- see each state page for direct links to official regulatory authorities.