What Is the CLES Certification?

What the Certified Laboratory Equipment Specialist credential means and why you may still see CLES even though it is no longer listed as a current AAMI exam

If you have worked in HTM for a while, you may have seen a credential written as:

Published August 28, 2026 · Revised September 6, 2026

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What Does CLES Stand For?

CLES stands for Certified Laboratory Equipment Specialist. The credential identifies HTM professionals with specialized knowledge of laboratory equipment, where troubleshooting may combine electronics and mechanics with temperature control, fluidics, optics, refrigeration, sample handling, and connections to laboratory information systems.

AAMI no longer lists CLES among the certification exams currently offered, although existing holders may still maintain and use the credential under ACI policies. That distinction matters: seeing CLES after a technician's name can still communicate meaningful laboratory experience, but a prospective candidate should check AAMI's current certification catalog instead of assuming a new CLES exam application is available.

What Kind of Equipment Did CLES Cover?

Laboratory equipment can include systems such as:

The exact equipment mix varies considerably between laboratories.

Laboratory Equipment Is a Specialty

A general biomed may understand:

But laboratory equipment adds areas involving:

Large Laboratory Analyzers

Modern analyzers may combine:

That makes them complex electromechanical systems.

Why Specialized Knowledge Matters

A chemistry analyzer failure could involve:

A technician needs to understand more than:

The machine has power.

CLES as a Legacy Credential

AAMI's current certification pages list active pathways such as:

CLES is not listed as a current new-exam certification.

However, AAMI still references existing CLES credential holders in current certification materials.

Existing CLES Holders Still Matter

Current AAMI materials still recognize CLES when discussing:

For example, current CHTM eligibility information recognizes CLES alongside credentials such as:

for one of its management-certification pathways.

Why You Still See CLES After Someone's Name

Someone may have earned CLES when the examination was available.

That credential does not suddenly become meaningless because the exam is no longer offered to new candidates.

Active vs Legacy Certification

This distinction is useful.

Active certification program

means new candidates can currently apply and test for it.

Legacy credential

means people may still legitimately hold the designation even though new testing is no longer offered.

Do Not Tell an Existing CLES Holder Their Credential Is Fake

CLES is a legitimate historical HTM credential.

The important point is:

It is not currently a standard new-certification path offered by AAMI.

Why Was CLES Created?

The basic idea was similar to CRES.

CBET covers broad biomedical equipment knowledge.

A specialty credential could recognize someone whose work was concentrated in:

Laboratory equipment.

Laboratory Equipment vs General Biomed

General biomed might include:

Laboratory support might include:

The troubleshooting foundation overlaps.

The technology does not always.

Centrifuges

A centrifuge may involve:

Incubators

An incubator may involve:

Refrigerators and Freezers

Laboratory refrigeration can be clinically critical because it may store:

depending on the application.

Analyzers

Modern laboratory analyzers may contain multiple subsystems.

Think:

Sample Handling

↓

Fluidics

↓

Reaction

↓

Measurement

↓

Software Result

A failure can occur anywhere in that chain.

Optics

Laboratory devices may use:

to measure chemical reactions.

Fluidics

Many analyzers move very small quantities of:

through:

Air leaks, restrictions, and contamination can create significant errors.

Temperature

Chemical reactions often depend strongly on temperature.

A small temperature error may matter much more than it would in some general-purpose equipment.

Calibration and Quality Control

Laboratory equipment operates in an environment where:

are central to patient-result reliability.

Lab Results Are Clinical Data

A device does not need to physically connect to a patient to create serious clinical risk.

A laboratory analyzer can generate information used to make treatment decisions.

That makes measurement accuracy critical.

Networking

Modern laboratory systems also connect to:

LIS

LIS generally means:

Laboratory Information System.

The analyzer may produce a correct result but still fail to transmit it.

Device vs Interface

If:

Analyzer result appears locally.

But:

Result does not appear in the LIS.

The measurement system may be fine.

Look downstream.

Service Model

Laboratory equipment is often heavily supported through:

That can affect how much in-house biomeds work directly on complex analyzers.

Why CLES May Have Become Less Common

HTM roles evolve.

Some specialty equipment is increasingly supported through:

The fact that the CLES examination is no longer currently offered does not mean laboratory technology stopped mattering.

Laboratory Equipment Still Appears in CBET

AAMI's current CBET outline specifically includes understanding and troubleshooting laboratory equipment such as:

So modern CBET candidates still need some laboratory-equipment knowledge.

What Certification Should a Lab-Focused Biomed Pursue Today?

Because CLES is not currently listed as a new AAMI examination, someone entering the profession today should look at currently available credentials such as:

CBET

for broad BMET certification.

Other training may come from:

Should Your Site Still Have a CLES Article?

Yes.

Because people still encounter:

CLES

in:

Someone searching:

What does CLES mean?

should be able to find a clear explanation.

This Is Also a Good Example of Why Certification Information Needs Dates

An old article may say:

Apply for the CLES exam.

That may have been correct when written.

It is misleading today.

Certification content should always indicate when it was reviewed.

CLES vs CRES

CLES:

Laboratory equipment specialty.

CRES:

Radiology/imaging specialty.

CRES remains a current AAMI examination.

CLES currently does not.

CLES vs CBET

CLES historically represented laboratory specialization.

CBET represents broader biomedical equipment knowledge and remains an active certification path.

Existing CLES and Career Advancement

An existing CLES credential may still have professional relevance.

AAMI's current CHTM eligibility information recognizes a current CLES certification as one possible qualifying professional credential when paired with the required management experience.

What Did You Actually Prove?

If someone has CLES after their name, you proved:

They earned the Certified Laboratory Equipment Specialist credential through the certification program when that pathway was available.

You should not assume:

They can currently retake or newly apply for the CLES examination.

And you should not tell a new technician:

Go sign up for CLES

without first checking whether the certification has been reintroduced.

A Useful Way to Think About CLES Today

Think:

Legitimate credential

but:

Legacy certification pathway.

Existing holders may still use it.

New technicians should review currently available certification options.

Final Thoughts

CLES is an important part of HTM certification history.

It recognized technicians who specialized in a part of healthcare technology that can be extremely complex:

Laboratory equipment.

That equipment combines:

and directly affects clinical laboratory results.

But certification programs change.

As of August 2026, AAMI still recognizes CLES as an existing credential in current materials, but it does not list CLES among its current new-candidate certification exams.

That distinction is worth making clear whenever the credential is discussed.

— Jake

Important Note

This article reflects publicly available AAMI information reviewed in August 2026. CLES is referenced by AAMI as an existing credential, but it is not currently listed among AAMI's active new-candidate certification examinations. Certification programs can change, so readers interested in a future or reinstated CLES pathway should verify current information directly with AAMI.

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