MLS (ASCP) - Medical Laboratory Scientist

  • Cost $240
  • Renews every 3 years


In Person


The American Society of Clinical Pathology (ASCP) grants the Medical Laboratory Specialist (MLS) certification to recognize healthcare professionals in medical laboratory science. A certified MLS conducts routine to complex laboratory tests in blood banking, chemistry, hematology, immunology, biology, and urinalysis to diagnose and treat diseases. MLS certification requires critical thinking skills to solve specimen, test, and instrumentation problems. Medical Laboratory Scientists work with physicians and other healthcare professionals to determine courses of action when treating patients.


  • Exam Fee: $240

  • International Candidate Fee: $200. There is a discount of $95 for applicants that have a medical laboratory education and reside in specific countries listed in the International Pricing Policy.

  • Fees will increase by $10 beginning July 1, 2023.

Course Format

Test Format

The MLS (ASCP) examination is a timed (2.5 hours), computer-based exam with 100 multiple-choice questions. The ASCP Board of Certification (BOC) administers the MLS certification exam using the format of Computer Adaptive Testing (CAT). The CAT format measures knowledge and skills more accurately than standard fixed-form tests. Test takers can't skip items because the CAT algorithm measures the individual’s ability level for each question answered. Each exam adjusts to the test takers’ knowledge level, and every exam is unique. 

The exam content covers areas within Medical Laboratory Science, including blood banking, urinalysis, chemistry, hematology, immunology, and lab operations. Examinations are scored on a scale of 0 to 999, with a minimum passing score of 400. The exam costs $240.

Exam Results

The computer-based exam is scored electronically. Applicants receive Pass/Fail results immediately at exam completion. The ASCP BOC emails a detailed score report within 24 hours. Successful applicants receive their certificates in the mail within 3 to 5 weeks of passing the exam.

In Person

Applicants take the MLS exam in-person at a Pearson VUE test center. They must report to the testing center 30 minutes before their scheduled test time. Applicants must supply a government-issued photo ID with a signature. The first and last name on this ID must match the name the applicant used to register for the exam.

Pearson VUE provides a locker to store all personal belongings, which can't be taken into the testing room. The Test Administrator (TA) may collect a digital photograph, digital signature, and/or palm vein image and complete other check-in procedures. Applicants receive a checklist of test taking rules to read. The exam is computer-based and monitored by the TA. There's no interaction allowed between test takers during the exam.


Steps to Obtain the MLS Certification

  • Determine your exam category and eligibility route

  • Log in or create an ASCP account

  • Complete the online application

    • Upload appropriate documentation as PDF files within the online application

  • Submit the non-refundable $240 application fee within 90 days of starting application

  • Request academic institution to send official transcripts to the ASCP BOC, if applicable

  • Monitor application status by logging into ASCP account to View the Status

    • Applicants receive emails notifications when changes in status occur

  • Resolve any deficiencies with the application

  • Await Admission Notification email

  • Schedule exam date with Pearson VUE

  • Prepare for exam day

  • Await official exam results

Eligibility Requirements: 

As of January 2022, the American Society of Clinical Pathology offers six options to meet eligibility requirements:

  1. Hold a Bachelor’s degree from a medical laboratory scientist program accredited by the National Accrediting Agency for Clinical Laboratory Sciences (NAACLS)

  2. Certification as a medical laboratory technician, plus a bachelor’s degree from an accredited institution plus two years of full-time clinical lab experience

  3. Certification as a clinical laboratory assistant, plus a bachelor’s degree, plus four years of professional experience 

  4. Hold a Bachelor’s degree plus five years of related work experience

  5. Current ASCP medical technician (MT)/medical laboratory science (MLS) certification, plus a bachelor’s degree from a regionally-accredited college or university, plus five years of full-time clinical experience

  6. Completion of a 50-week US military medical laboratory training course in the past ten years, plus a bachelor’s degree plus one year of full-time clinical experience

Once eligibility is met, candidates must apply for the certification exam. The application for MLS certification is completed online through an ASCP account. MLS candidates must submit the application fee within 90 days of the application start date.

Candidates who pass the exam receive a notification via email to view their exam score within four business days of completing the exam. They receive their wall certificates in approximately 3 to 5 weeks for U.S. mail and 6 to 9 weeks for International mail.

Candidates who are unsuccessful at passing the exam may reapply. They may retake the exam up to five times under the same eligibility route. If they fail five times under this route, they must meet the eligibility requirements under an alternate eligibility route. If they don't meet any of the alternate requirements, they're no longer eligible to apply for the MLS exam. Each time an applicant applies to take the MLS exam, they must pay the full $240 application fee.


Certified medical lab scientists must renew MLS certification every three years. MLS certification renewal requires 36 points in continuing education activities defined by the Credential Maintenance Program (CMP).

Renewal Fee

  • Renewal fee: $95

  • Reinstatement fee: $125

  • Fee is reduced by $15 if renewing multiple ASCP certifications that expire on the same day or will expire in three months of each other.

Continuing Education

Effective 1/1/2023, all certification categories are required to complete one CMP point of continuing education in the area of medical ethics (e. g., HIPAA, compliance, confidentiality training.)

Other Resources

The ASCP offers the following resources for exam candidates, including:

Related Certifications

The ASCP offers other certifications, including:

  • Technologist in Microbiology (M)

  • Technologist in Molecular Biology (MB)

  • Specialist in Chemistry (SC)

  • Diplomate in Laboratory Management (DLM)

  • Specialist in Blood Banking (SBB)

  • Specialist in Molecular Biology (SMB)

Was this page helpful?

Related Jobs

View job details for Medical Technologist
Staff Position

Medical Technologist

  • Mercy Medical Center Mary Catherine Bunting Center
  • Baltimore, MD
  • evenings
  • Sign-On Bonus
From the web
View job details for Medical Technologist
Staff Position

Medical Technologist

  • Mercy Medical Center Mary Catherine Bunting Center
  • Baltimore, MD
  • nights
  • Sign-On Bonus
From the web
View job details for Medical Lab Scientist
Staff Position

Medical Lab Scientist

  • Oak Point University, IL
  • Chicago, IL
  • Sign-On Bonus
From the web
View job details for Medical Technologist
Staff Position

Medical Technologist

  • LifeSouth Community Blood Centers
  • Atlanta, GA
  • evenings
  • Sign-On Bonus
Posted 4 days ago
From the web
View job details for Medical Technologist
Staff Position

Medical Technologist

  • City of Philadelphia, PA
  • Philadelphia, PA
  • Sign-On Bonus
From the web

Frequently asked questions

Is the MLS exam difficult?

Of the 5,411 people who've attempted the MLS exam since the first year of testing (1931), 69% of them passed the exam, according to ASCP’s 2021 exam statistics. Of the 3,021 candidates who took the exam through CAAHEP/NAACLS eligibility routes, 79% passed it on their first attempt.

How long should you study for MLS?

A medical laboratory scientist career requires a 4-year degree and up to 5 years of relevant work experience, depending on the education path. Therefore, achieving the MLS certification may take 4 to 9 years of study in medical laboratory science.

What are some certifications I can pursue after obtaining MLS (ASCP) certification?

You can pursue Technologist in Microbiology (M-ASCP), Technologist in Molecular Biology (MB-ASCP), Specialist in Chemistry (SC-ASCP), Diplomate in Laboratory Management (DLM-ASCP), Specialist in Blood Banking (SBB-ASCP) or Specialist in Molecular Biology (SMB-ASCP), among others.

How do I pass the MLS (ASCP) exam?

To earn a passing score, you must earn at least 400 points or more on the exam. Most tests span two hours and 30 minutes and test takers tackle 100 multiple-choice ASCP exam questions related to the knowledge and skills involved in performing essential tasks in the medical laboratory.

When did ASCP change from MT to MLS?

The Medical Technologist (MT) certification changed to the Medical Laboratory Scientist (MLS) certification in 2009.

What other certification does the ASCP offer besides the MLS?

The American Society of Clinical Pathologists (ASCP) also offers the following certifications:

  • Specialist in Microbiology (SM)

  • Specialist in Cytometry (SCYM)

What organization offers the MLS?

The American Society of Clinical Pathologists (ASCP) offers the MLS.