CLS - Clinical Laboratory Scientist

A Clinical Laboratory Scientist (CLS) is also known as a Medical Laboratory Scientist (MLS), so certification is the same for both professionals. This professional credential signifies a high level of proficiency and knowledge in laboratory sciences. It’s designed for individuals who perform a full range of laboratory tests and play a crucial role in diagnosing and treating diseases. This certification is often required for working in hospital laboratories, research labs and diagnostic labs. The American Society for Clinical Pathology (ASCP) is the certifying body for CLS/MLS certification, recognized for its rigorous standards and comprehensive examination.

Eligibility

As of January 2024, 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 5 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 CLS/MLS certification is completed online through an ASCP account. 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 scores within 4 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.

Unsuccessful candidates may reapply. They may retake the exam up to 5 times under the same eligibility route. If they fail 5 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 CLS/MLS exam. Each time an applicant applies to take the CLS/MLS exam, they must pay the full $250 application fee.

Completion Time: 2.5 hours

Cost: $250 nonrefundable

Exam Format

Applicants have 2.5 hours to complete the CLS/MLS exam, which has 100 multiple-choice questions with one right answer. Testers can’t skip 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 scaled score of 400. 

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.

Application Process

Steps to Obtain the CLS/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 the ASCP account to View the Status

  • Applicants receive email 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

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

Renewal Fees

• 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 within three months of each other.

Beginning July 1, 2024:

• CMP fees for all credentials will increase by $5.

• CMP reinstatement fees for all credentials will increase by $10.

• CMP fees for additional credentials will increase by $5.

• CMP fees are non-refundable.

MLS certification renewal requires 36 points in continuing education activities defined by the Credential Maintenance Program (CMP).

Required point distribution for CLS/MLS certification renewal includes:

• 2 points in each category: blood banking, chemistry, hematology and microbiology

• 1 point in laboratory or patient safety

• 1 point in medical ethics

• 26 points in lab specialty, immunology, molecular diagnostics, management, education or other related laboratory areas of interest

Beginning with certification cycles expiring in January 2024 and going forward, revised CMP requirements will increase the points required in blood banking, chemistry, hematology and microbiology from 2 to 8, but the other total CMP points won’t increase.

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

• Content Outline

• Reading List

• Exam and Certification Procedures

• Review Course (Cost: $59 for non-members and $49 for members)

• Practice Exam (Cost: $99 for non-members and $89 for members)

• Study Guide and Review Course (Cost: $129 for non-members and $109 for members)

• Study Guide, Review Course and Practice Exam (Cost: $139 for non-members and $119 for members)

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)