What Is a Medical Laboratory Scientist? The Healthcare Career Behind Most Diagnoses
Medical laboratory scientists run the tests doctors rely on to diagnose and treat patients. Here's what the job involves, how to become one in as little as a year after a science degree, and who it suits.
By Saima Ahmad, MPH· 2 min read
When a doctor orders a blood count, checks for an infection, or matches blood for a transfusion, someone has to run that test accurately and quickly. That someone is a medical laboratory scientist (MLS).
I've spent more than 25 years in clinical laboratories, and this is the career I wish more students knew about. It's essential, it's in demand, and many people have never heard of it.
What a medical laboratory scientist does
MLS professionals work in hospital and reference labs, analyzing patient samples such as blood, urine, and tissue fluids. The work usually rotates through several departments:
- Chemistry: glucose, electrolytes, kidney and liver function, cardiac markers
- Hematology: blood counts and blood-cell abnormalities, including signs of leukemia
- Microbiology: identifying bacteria and fungi and testing which antibiotics will work
- Blood bank (transfusion medicine): blood typing and crossmatching so transfusions are safe
- Immunology and molecular testing: antibodies, viral loads, and DNA-based tests
It's detail-heavy, science-driven work. You operate and troubleshoot sophisticated analyzers, run quality control, and call critical results to physicians and nurses. There's little direct patient contact but a lot of responsibility: your results guide treatment decisions every day.
How to become a medical laboratory scientist
There are three common routes:
- A bachelor's degree in medical laboratory science from a NAACLS-accredited program. Clinical rotations are built in.
- A science bachelor's plus a post-baccalaureate certificate. If you already have a biology or chemistry degree, a 12-month NAACLS-accredited hospital or university program gets you ready for certification. This is one of the fastest routes into healthcare for science graduates.
- Start as a medical laboratory technician (MLT) with a two-year associate degree, then complete an MLT-to-MLS bridge program while working.
After your program, you take the ASCP Board of Certification MLS exam. A few states, including California, New York, and Florida, also require a state license.
See the full MLS route or the MLT route.
Related laboratory careers
The lab has specialties for people drawn to specific kinds of work:
- Cytotechnologists screen cells under the microscope to find cancer and pre-cancer. Cytotechnology route.
- Histotechnicians and histotechnologists prepare the tissue slides that pathologists use for diagnosis. Histotechnology route.
Lab experience also leads to leadership: supervisor, lab manager, quality and compliance, and laboratory director roles.
Is it a good fit for you?
Medical laboratory science tends to suit people who:
- Enjoy science and problem-solving more than bedside care
- Like precision, procedures, and getting things exactly right
- Stay calm under time pressure, since emergency results can't wait
- Want a healthcare career without many more years of school
For current pay and job outlook, check the Bureau of Labor Statistics page for clinical laboratory technologists and technicians, which is updated every year.
If you want a behind-the-scenes role where your work matters to every patient, the lab is worth a serious look.
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