Neither national credential is mandatory at the national level: ASHA describes its C-AA as a voluntary credential that does not substitute for state licensure or registration, and CAOHC says its COHC is not mandatory under OSHA.
Whether you must hold one is decided state by state — Texas, for one, counts a CAOHC certificate toward its assistant license — with employer requirements on top.
This page compares the C-AA, the COHC and the military routes: fees, exams, renewal and how state registration changes the picture.
Is certification required to work as an audiology assistant?
Neither of the two national credentials for this role is mandatory at the national level.
ASHA describes its C-AA as a national, voluntary credential that is not interchangeable with state licensing laws and does not automatically qualify a holder for state licensure or registration.
CAOHC likewise states that its COHC certification is not mandatory under OSHA, though it documents at least 20 hours of training and a passed national exam.
What governs is your state, and a state can make a credential count: Texas accepts a CAOHC certificate as one route to its assistant license.
ASHA says support personnel licensure varies from state to state, and its scope-of-practice document for assistants does not supersede state laws that require licensure or registration of support personnel.
Employers can add a layer on top: a job posting can require a credential the state does not, so read each posting's requirements on its own terms.
Requirements change — verify before you apply or hire
ASHA C-AA: the audiology assistant certification
ASHA — the American Speech-Language-Hearing Association — abbreviates its credential for this role C-AA, short for Audiology Assistants Certification.
It is a national certification, not a license, and holding one is voluntary.
The credential is recent: ASHA's renewal page distinguishes C-AA holders who applied before and after April 15, 2021, so it has been offered since at least early 2021.
Eligibility runs through one of three education pathways.
- Pathway one: a bachelor's degree in communication sciences and disorders (CSD) plus 500 hours of supervised field work.
- Pathway two: a different college degree, a high school diploma or a GED, plus ASHA's online audiology education modules (or an equivalent assistant program) plus 1,000 hours of supervised field work.
- Pathway three: a military audiology or ENT job series certificate.
Field work has to sit inside ASHA's Scope of Practice for Audiology Assistants, under the supervision of an ASHA-certified audiologist.
All three pathways also require prerequisite courses, including one-hour courses in universal safety precautions and patient confidentiality, completed no more than two years before you apply.
Plan the calendar as well: ASHA asks for up to six weeks to review an application after the last document arrives.
The Assistants Certification Exam has 100 multiple-choice questions, is administered by Prometric at test centers or online, and the passing score for audiology assistants is 162.
Candidates get one year from approval to test and may sit the exam up to three times in that year; each retest costs $99.
The initial certification fee is $249, which includes the exam and up to two years of certification and benefits; annual renewal is $125, due December 31.
Those are ASHA's posted fees as of October 2026.
Keeping the C-AA runs on a three-year interval: holders complete ASHA's certification maintenance assessment module (MOCA) in the third year, follow the Assistants Code of Conduct, and keep paying the annual fee.
There is no separate charge for the MOCA.
The certification maps onto ASHA's 2022 scope for assistants: testing without clinical interpretation — hearing screening, pure-tone air conduction thresholds, newborn hearing screening, immittance and OAE screening, and nondiagnostic otoscopy.
ASHA's scope is explicit about the flip side: assistants should not diagnose, interpret results, counsel, recommend or fit devices, or present themselves as audiologists.
What that looks like shift to shift is the role's own question — the audiology assistant career guide covers the day-to-day work.
CAOHC COHC certification for assistants
The Council for Accreditation in Occupational Hearing Conservation (CAOHC) runs the Certified Occupational Hearing Conservationist (COHC) credential — a certification a technician can earn to perform audiometric testing in a workplace hearing conservation program.
Becoming a COHC takes a CAOHC-approved 20-hour course plus the exam given at the end, and there are no prerequisites.
The exam covers only material presented in the course.
Both the 20-hour certification course and the 8-hour recertification course require passing a national standardized written exam plus practical exams on audiometric testing and hearing protector fitting.
CAOHC's course search lists in-person, hybrid and virtual options.
Fees are set by each Course Director and vary by location; CAOHC does not publish a single course price or handle registration.
Certification runs on a five-year cycle, and the clock starts on the date you completed the course — not the exam date.
If you cannot recertify in time, request an extension at least 30 days before expiry.
CAOHC does not grant extensions after expiration, and a certificant who lapses without one retakes the full 20-hour course.
OSHA's own rule is broader than any one credential.
Under 29 CFR 1910.95(g)(3), audiometric tests may be performed by a licensed or certified audiologist, an otolaryngologist or other physician, or a technician who is CAOHC-certified or has satisfactorily demonstrated competence in testing and audiometer use.
The scope is narrower than clinic assistant work.
COHC training does not qualify anyone — unless also a licensed audiologist or physician — to do testing beyond pure-tone air conduction, so no bone conduction or speech audiometry.
Military training counts only partway here: DoD-trained hearing technicians holding a CAOHC-approved DOEHRS certificate have completed the practicum portion, but they must still pass the CAOHC exam and pay the exam fee to become COHCs.
CAOHC's other credential is not an assistant rung: the Certified Professional Supervisor of the Audiometric Monitoring Program (CPS/A) is open only to audiologists and physicians with a current practitioner license, though other professionals may take the course without sitting the exam.
State registration requirements for audiology assistants
State law is where "required" can flip.
ASHA keeps an interactive map of the states whose laws and regulations accept its assistant certifications — the C-AA and the speech-language pathology assistant credential — as an option or as a way to meet the full requirements to practice as an assistant.
ASHA's scope document does not override any of it: where a state requires licensure or registration of support personnel, assistants follow that state's rules.
Texas shows how concrete a state requirement gets.
Texas licenses an "assistant in audiology".
The application is $150 for a two-year license.
Applicants need at least a high school diploma plus a CAOHC certificate, or a bachelor's degree in communicative sciences or disorders instead.
They also sit the Texas jurisprudence exam and file an approved supervision plan with a licensed audiologist.
Notice what Texas counts toward its state license: a CAOHC certificate.
The state, not ASHA, issues the license.
That split — national credential versus state credential — is the pattern to check in your own state.
Titles vary as much as rules.
"Audiology assistant" is the title ASHA's credential uses, Medicare's rules speak of audiological aides, assistants and technicians, and CAOHC's credential names the occupational hearing conservationist.
CAOHC's FAQ describes state registration rules aimed at audiometric technicians.
Our research did not confirm those state rules against the regulations themselves, so ask your state's labor department, health department or audiology board which titles it regulates.
Four questions to start with: whether support personnel must register, what the state calls the credential, whether the C-AA counts toward it, and what supervision the state expects.
Which credential do employers prefer?
Our research found no published data ranking one credential above another in audiology assistant hiring, so treat any blanket "employers prefer X" claim with suspicion.
Requirements are set by each employer, on top of whatever your state requires.
What each credential documents is concrete, and that is what an employer is hiring.
The C-AA documents supervised field work inside ASHA's scope, a passed 100-question exam and the Assistants Code of Conduct its holders follow.
The COHC documents a 20-hour CAOHC-approved course, passed practical exams in audiometric testing and hearing protector fitting, and a passed national written exam.
CAOHC describes that training as proof a technician has met a high standard — a minimum of 20 hours of instruction.
Both credentials can be verified online.
CAOHC runs an online verification tool that employers and the public can use to confirm a current CAOHC credential, and ASHA runs a free online verification system for its certifications.
One boundary matters to practices that bill Medicare.
CMS's Benefit Policy Manual (chapter 15, section 80.3.1) defines a qualified audiologist as someone with an audiology master's or doctorate who is licensed in the state where services are furnished, or who meets alternative requirements in a state without licensure.
Medicare is not authorized to pay for audiological tests performed by aides, assistants or technicians who do not meet that definition.
No assistant certification moves that line.
Credentials document what you are trained to do; Medicare's rule decides what it pays for.
Hiring rather than job-hunting?
Our hearing care hiring hub is the employer's starting point for hiring an audiology assistant.
Next steps
Order matters here: the state decides whether you must hold anything, the credential you choose documents the training, and the employer decides what it wants on top.
Work through them in that order.
Check your state first
Your state's audiology licensing board or health department decides whether support personnel must register and what the credential is called. State rules come first — ASHA's own scope document defers to them.Map your C-AA pathway
Pick the pathway that fits your education: a CSD bachelor's with 500 supervised hours, the module route with 1,000 hours, or a military audiology or ENT certificate. Add the prerequisite courses, including safety and confidentiality, if you have not taken them.Budget the fees and the timeline
Plan around the $249 initial fee and the $125 annual renewal, allow up to six weeks for application review, and use your one-year testing window — up to three attempts, at $99 per retest.Occupational route? Look at CAOHC
If workplace hearing conservation is your target, search CAOHC's course list for an approved 20-hour course in person, hybrid or virtual, and calendar the five-year renewal from your course completion date.
Whichever route you take, the credential is not the whole picture: ASHA's scope document defers to state licensure law, and Medicare is not authorized to pay for audiological tests performed by aides, assistants or technicians who do not meet its qualified-audiologist definition.
Career information, not licensing, legal, medical, clinical, billing or coding advice. Requirements, fees and state rules change — confirm current details with ASHA, CAOHC and your state's licensing board or health department.