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Medical Laboratory Scientist (MLS)
Find the current format, timing, scoring, fees, eligibility, and testing options for AMT MLS, with direct links to official sources.
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Questions210 four-option multiple-choice questions (per the current content outline; AMT embeds unscored pretest items in its exams, and the handbook gives a 200–230 item range across AMT examinations)
Testing time3.5 hours
ScoringScaled score 0–100; pass requires a scaled score of 70 or greater
Exam feeUSD 245 (non-refundable; includes application, exam, and first annual fee); USD 225 for candidates residing outside North America; USD 245 retesting fee
Prep options
Study resources for AMT MLS
Independent prep
Courses and study resources
Exam overview
What to know before choosing your prep
- Who runs it
- AMT
- Category
- Medical Laboratory
- Current version
- Current MLS (AMT) "Competencies and Examination Specifications" content outline (©2026); no public version code or edition label
- Where it applies
- United States — national
- Exam languages
- English
- Score scale
- 0–100 scaled scores (not percentages)
- Testing provider
- Pearson VUE
- Format
- Computer-based at Pearson VUE test centers; OnVUE online proctoring also available
- Availability
- Year-round by appointment (nearly every day except Sundays and holidays), after AMT application approval
- Results
- Preliminary results displayed on screen immediately at the test center, with a printed results copy
- Remote testing
- Available
Exam structure
Single computer-delivered exam of 210 four-option multiple-choice items (single best answer) across nine work areas: General Laboratory 21.0% (44 items), Chemistry 18.1% (38), Hematology 15.2% (32), Coagulation and Hemostasis 4.7% (10), Immunology and Serology 3.3% (7), Immunohematology 10.5% (22), Blood Banking and Transfusion Services 7.6% (16), Microbiology 12.4% (26), Urinalysis and Body Fluids 7.1% (15)
Where rules vary
U.S. national certification; the exam page links "State Licensure Authorities Recognizing AMT Exams for MLS and MLT" and AMT notes California LFS approval of the MLS exam, but the exam itself is one uniform national test.
Eligibility
One of three eligibility routes: (1) baccalaureate degree from a NAACLS/accredited MLS program within the last 5 years; (2) baccalaureate degree plus an accredited MLT program or a 50-week US military medical laboratory training program within the last 5 years; (3) baccalaureate degree with at least 48 semester hours of MLT/clinical laboratory science or related coursework plus one year (2,080 hours) of approved clinical laboratory experience within the last 5 years; clinical rotations/experience across Blood Banking, Microbiology, Chemistry, and Hematology required on all routes
Retake policy
Retake permitted 45 days after a failed attempt; limited to 4 exam attempts per certification; retesting fee USD 245