MLS study guide
MLS · Work through your exam, one topic at a time.
The Medical Laboratory Scientist (MLS) credential is awarded by the ASCP Board of Certification (BOC), the certification body associated with the American Society for Clinical Pathology. It is the entry-level professional credential for laboratory professionals who perform and interpret clinical testing across the full laboratory - generalist scientists as well as those working in hospital, reference, public health, and physician-office laboratories. The MLS study guide has 8 sections and about 2,240 words.
01Blood Bank / Immunohematology
Blood bank questions reward system-level reasoning: you predict what an antibody will do in vivo, then pick the safest product under time pressure. Know ABO genetics and the reciprocal isohemagglutinins of Landsteiner's rule, why anti-A and anti-B are IgM and complement-activating, and why anti-D and most other significant antibodies are IgG that react at 37 °C and in the indirect antiglobulin test.
322 words, about 2 min02Clinical Chemistry
Chemistry questions test whether you can trace a number back to preanalytical and analytical causes. Master spectrophotometry and Beer's law, then distinguish reference intervals, decision limits, and critical values.
290 words, about 1 min03Hematology and Hemostasis
Start with the CBC and derived indices, then classify anemia by MCV. Microcytic: iron deficiency (low ferritin, high TIBC, low saturation, high RDW), thalassemia trait (normal or high ferritin, normal RDW, target cells, Mentzer index below 13), anemia of chronic disease (low TIBC, high ferritin).
282 words, about 1 min04Microbiology
Build a decision tree from specimen to organism to susceptibility. Know Gram stain reaction and morphology, then media: sheep blood agar, chocolate, MacConkey (lactose fermenters pink), Columbia colistin-nalidixic acid, mannitol salt, bile esculin, XLD and Hektoen, thioglycollate, and anaerobic media.
236 words, about 1 min05Immunology and Serology
Separate innate from adaptive immunity, then know immunoglobulin structure and function: IgG crosses the placenta and dominates the secondary response, IgM is a pentamer marking recent exposure, IgA guards mucosa, IgE arms mast cells. Trace the classical, alternative, and lectin complement pathways and what CH50 measures.
281 words, about 1 min06Urinalysis and Body Fluids
Work through physical, chemical, and microscopic phases. Specimen: first-morning midstream, timely analysis, appropriate preservative.
292 words, about 1 min07Molecular Diagnostics
Follow the workflow: specimen, nucleic acid extraction, amplification or hybridization, detection, interpretation. Know polymerase chain reaction stages and real-time chemistry (hydrolysis probes, molecular beacons, intercalating dyes), and that the cycle threshold is inversely proportional to starting target; roughly one cycle equals a two-fold difference.
265 words, about 1 min08Laboratory Operations and Management
Know the regulatory frame: CLIA certificate types and test complexity categories (waived, moderate, high), personnel qualification requirements, and accreditation by CAP or The Joint Commission. Distinguish method verification (FDA-cleared method adopted by the laboratory) from validation (laboratory-developed or modified method).
272 words, about 1 min