CLS Exam Preparation
Everything you need to pass your CLS, MLS, or MT certification exam — 350+ practice questions, study guides, and topic reviews for all major board areas.
Chemistry
79 questions
Hematology
73 questions
Microbiology
72 questions
Blood Bank
66 questions
Immunology
60 questions
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Why Use Our Exam Prep
Built by lab professionals who've been through the certification process. Here's what makes our prep different.
Board-Aligned Content
Questions are mapped to ASCP and AMT content outlines. We cover Chemistry, Hematology, Microbiology, Blood Bank, Immunology, and Lab Operations.
Learn From Explanations
Every question includes a detailed rationale. Understand why answers are correct and why distractors are wrong.
Completely Free
No paywalls, no account required. Practice as much as you need, whenever you need, 100% free.
CLS Exam Topics & Study Guides
Comprehensive study guides for every major topic on the ASCP and AMT board exams.
Clinical Chemistry
Cardiac markers (troponin, CK-MB), liver function tests, renal function, electrolytes, acid-base balance, therapeutic drug monitoring, and endocrinology.
- • Key enzymes and their clinical significance
- • Reference ranges and critical values
- • Quality control and method validation
Hematology & Coagulation
CBC interpretation, WBC differentials, anemia classification, hemoglobinopathies, coagulation cascade, PT/PTT/INR, and platelet disorders.
- • Cell morphology and identification
- • Coagulation factor pathways
- • Normal hematology reference ranges
Clinical Microbiology
Gram-positive and gram-negative bacteria identification, fungal cultures, viral testing, antibiotic susceptibility testing, and infection control.
- • Gram stain morphology and biochemical tests
- • Culture media and incubation requirements
- • Antimicrobial resistance mechanisms
Blood Bank & Transfusion
ABO and Rh typing, antibody screening and identification, crossmatching, hemolytic disease of the newborn, and transfusion reactions.
- • ABO blood group system and Rh factors
- • Antibody detection methods
- • Donor screening and component therapy
Immunology & Serology
ELISA, Western blot, flow cytometry, autoimmune disease markers, hypersensitivity reactions, and immunodeficiency testing.
- • Immunoglobulin classes and functions
- • Autoantibody testing methods
- • Complement cascade and immune complexes
Lab Operations & QC
CLIA regulations, quality control procedures, statistical analysis, laboratory safety, phlebotomy techniques, and specimen handling.
- • Westgard rules and QC interpretation
- • CLIA waived vs. moderate vs. high complexity
- • Chain of custody and legal issues
CLS Exam Study Tips
Strategies to help you pass the ASCP, AMT, or NCA board exam on your first attempt.
Focus on High-Yield Topics
Chemistry, Hematology, and Microbiology make up the largest portion of the ASCP exam. Prioritize these areas while still reviewing Blood Bank and Immunology regularly.
Practice with Time Limits
The ASCP board exam gives you about 60 seconds per question. Use our timed practice sessions to build speed and accuracy before test day.
Review Incorrect Answers Thoroughly
Each practice question includes detailed explanations. Understanding why an answer is correct — and why others are wrong — is the most effective way to learn.
Take Multiple Practice Sessions
Questions are randomly selected each session, so take the quiz multiple times to expose yourself to a wider range of topics and question formats.
Know Your Reference Ranges
Many exam questions test normal and critical values. Memorize common reference ranges for chemistry analytes, hematology parameters, and coagulation studies.