ASCP Board of Certification
ASCP MLS
ASCP Board of Certification Medical Laboratory Scientist (MLS)
The certification for medical laboratory scientists who perform and interpret clinical lab tests; required for employment in most clinical laboratories.
Blueprint-complete program: 7 decks, 914 cards.
What's on the exam
ASCP BOC MLS Content Guideline
Blood Banking / Immunohematology
18%ABO and Rh blood groups · Antibody identification and screening · Compatibility testing and crossmatch · Transfusion reactions and components · Hemolytic disease of the newborn
Body Fluids and Urinalysis
8%Urine physical, chemical and microscopic · CSF and serous fluids · Renal function · Fecal and other body fluids
Chemistry
20%Carbohydrates, lipids and proteins · Enzymes and cardiac markers · Electrolytes and blood gases · Endocrinology and therapeutic drug monitoring · Instrumentation and QC
Hematology
18%RBC, WBC and platelet morphology · Anemias and hemoglobinopathies · Leukemias and WBC disorders · Coagulation and hemostasis · CBC and cell counts
Immunology / Serology
8%Antigen-antibody reactions · Autoimmune and hypersensitivity · Infectious disease serology · Complement and immunoglobulins
Microbiology
20%Bacteriology and identification · Antimicrobial susceptibility · Mycology, parasitology and virology · Specimen collection and culture · Gram stain and media
Laboratory Operations
8%Quality control and assurance · Laboratory safety · Lab math and method evaluation · Regulations (CLIA) and informatics
Frequently asked questions
How much does the ASCP MLS cost?
The ASCP MLS costs $250. Application fee.
How long is the ASCP MLS and how many questions does it have?
100 questions — 2.5 hours.
What do you need to pass the ASCP MLS?
Scaled score of 400.
Can you retake the ASCP MLS?
After 30 days; up to five attempts.
What is the best way to study for the ASCP MLS?
Study the official blueprint, not random material: the exam is weighted by domain (Blood Banking / Immunohematology 18%, Body Fluids and Urinalysis 8%, Chemistry 20%, Hematology 18%, Immunology / Serology 8%, Microbiology 20%, Laboratory Operations 8%). Spaced-repetition flashcards built domain-by-domain against that blueprint are the most time-efficient way to cover everything the exam tests.
Ready to prepare?
Our ASCP MLS — Medical Laboratory Scientist program follows this exact blueprint — every domain covered, scheduled by spaced repetition, with a journey from first card to test day.