Becoming a medical laboratory scientist (MLS) requires a bachelor’s degree in a science field and completion of a clinical training program, followed by a national certification exam. The full path takes about four years if you start from scratch, or as little as 12 months if you already hold a science degree. Here’s what each step looks like.
Step 1: Earn a Bachelor’s Degree
You need a bachelor’s degree with a strong foundation in biology and chemistry. Most people either major in medical laboratory science directly or earn a degree in biology, chemistry, or a related life science and then complete clinical training separately. If your university offers a dedicated MLS program, you’ll typically take your science prerequisites in the first two years and move into MLS-specific coursework and clinical rotations in the final two.
Regardless of the path you choose, you’ll need at least 16 semester hours in biology (including microbiology) and 16 semester hours in chemistry (including organic chemistry or biochemistry). These specific credit thresholds come up repeatedly in certification eligibility requirements, so plan your course schedule around them early.
Step 2: Complete a NAACLS-Accredited Program
This is the single most important credential decision you’ll make. Programs accredited by the National Accrediting Agency for Clinical Laboratory Sciences (NAACLS) meet standardized quality benchmarks, and graduating from one gives you a direct path to sit for the certification exam. Many employers prefer or require graduates from accredited programs, and in states that mandate licensure, accreditation is often a prerequisite for obtaining your license.
NAACLS-accredited programs include both four-year university programs (where clinical training is built into the degree) and standalone professional programs you enter after completing prerequisite coursework. The clinical component typically involves around 16 weeks of hands-on rotations in a hospital or reference laboratory, divided across disciplines like hematology, microbiology, blood banking, and clinical chemistry. During rotations, you work with patient specimens under supervision, learning to run both routine and complex tests.
Step 3: Pass the Certification Exam
The most widely recognized credential is the MLS(ASCP), administered by the American Society for Clinical Pathology’s Board of Certification. The exam covers blood banking, chemistry, hematology, immunology, microbiology, molecular biology, and urinalysis. It’s a computer-based test, and you can schedule it at testing centers across the country.
There are multiple eligibility routes for the exam:
- Route 1 (most common): A bachelor’s degree plus completion of a NAACLS-accredited MLS program within the last five years.
- Route 2: A valid MLT(ASCP) certification (the technician-level credential), a bachelor’s degree meeting the biology and chemistry credit requirements, and two years of full-time clinical laboratory experience within the last five years.
- Route 4: A bachelor’s degree meeting the biology and chemistry credit requirements plus five years of full-time clinical experience.
Route 1 is the most straightforward. Routes 2 and 4 exist for people who entered the field at the technician level or gained experience before pursuing full certification.
If You Already Have a Science Degree
You don’t need to start over. Several universities offer post-baccalaureate certificate programs designed specifically for people who hold a bachelor’s degree in biology, chemistry, or another science and want to transition into MLS. These programs focus on the clinical laboratory coursework and rotations you’re missing, skipping the general education and prerequisite science classes you’ve already completed.
Program length varies. Some certificate tracks run 12 months (the University of North Dakota and the University of Arkansas for Medical Sciences both offer 12-month options). Others take three to four semesters. Several programs deliver didactic coursework online, which can make it easier to study while managing other obligations. Texas Tech University Health Sciences Center and the University of Texas Medical Branch, for example, offer online MLS coursework for students who already hold a four-year science degree. You’ll still need to complete clinical rotations in person at a partnering hospital or lab.
State Licensure Requirements
National certification is the baseline, but ten states also require a separate state-issued license before you can practice: California, Florida, Hawaii, Louisiana, Montana, Nevada, New York, North Dakota, Tennessee, and West Virginia. Licensure requirements vary by state and may include additional applications, fees, or examinations. If you plan to work in one of these states, check its specific requirements early so you’re not caught off guard after graduation.
In the remaining 40 states, your ASCP certification is generally sufficient to begin working, though individual employers may have their own preferences.
MLS vs. MLT: Understanding the Difference
Medical laboratory technicians (MLTs) and medical laboratory scientists (MLSs) both run lab tests that help diagnose disease, but the roles differ in complexity and autonomy. Technicians typically hold an associate’s degree, perform more routine and automated testing, and work under the supervision of a technologist or lab manager. Scientists hold a bachelor’s degree, perform more complex manual tests, and carry greater responsibility for quality assurance across the laboratory.
Starting as an MLT can be a practical entry point if you want to work in the field sooner. You can gain experience, earn a paycheck, and later pursue your bachelor’s degree and MLS certification through Route 2. The tradeoff is that the total timeline may end up longer than going directly through a four-year program, and you’ll need to accumulate two years of clinical experience before you’re eligible for the MLS exam.
What You’ll Actually Do on the Job
Medical laboratory scientists perform the tests that drive roughly 70% of medical decisions, though most patients never meet the person running their bloodwork. Your day-to-day involves analyzing blood, urine, tissue, and other biological specimens using both automated instruments and manual techniques. You might type and crossmatch blood for a transfusion, identify bacteria from a wound culture, count blood cells to help diagnose anemia or leukemia, or run chemistry panels that reveal how well a patient’s liver or kidneys are functioning.
Most MLS positions are in hospitals, but opportunities also exist in reference laboratories, public health agencies, research institutions, forensic labs, and the pharmaceutical industry. Shift work is common, especially in hospitals, since labs operate around the clock. Many scientists work evenings, nights, or weekends, particularly early in their careers.
Career Outlook and Salary
Demand for clinical laboratory professionals remains strong. An aging population that needs more diagnostic testing, combined with a wave of retirements in the current workforce, has created consistent job openings across the country. The Bureau of Labor Statistics groups technologists and technicians together in its projections and reports steady growth for the field.
Starting salaries vary by region and employer, but the field offers solid middle-class pay with room for advancement. With experience, you can move into supervisory roles, laboratory management, quality assurance, education, or specialized areas like molecular diagnostics. Some scientists eventually pursue graduate degrees to move into pathology, research, or laboratory administration.