- The Short Answer: What the Letters Spell Out
- Why the Acronym Causes So Much Confusion
- Who Stands Behind This Credential
- What a Council-certified Microbial Consultant Actually Does
- The Six Exam Domains Behind the Name
- Exam Format at a Glance
- Who Qualifies to Use the Title
- Fees, Validity and Renewal
- CMC Versus Its Closest Relatives
- Getting Started Without Wasting Time
- Frequently Asked Questions
- Here, CMC means Council-certified Microbial Consultant, issued by the American Council for Accredited Certification (ACAC).
- The exam has 120 multiple-choice questions, three hours, closed book, with a 75% passing score.
- Six official domains cover biology, health effects, investigation, sampling, remediation and Health & Safety.
- Initial certification totals $500 for a two-year term; renewal is $400 and requires 40 recertification credits.
The Short Answer: What the Letters Spell Out
On this site, CMC stands for Council-certified Microbial Consultant. It is a professional certification for people who design, conduct and interpret microbial sampling and investigation work, typically in buildings and indoor environments. The credential is awarded by the American Council for Accredited Certification (ACAC) through its CMC Certification Board.
That is the entire expansion, and it is worth stating plainly because the same three letters appear on very different credentials in other industries. If you landed here from a search for the meaning of the acronym, you may be looking for something else entirely. If you are working in mold assessment, indoor air quality, building science or industrial hygiene, you are in the right place. For broader background, see our explainers on what CMC is and CMC meaning.
Why the Acronym Causes So Much Confusion
Search for "CMC" and you will find results spanning management consulting, nursing, pharmaceutical manufacturing and more. None of those are what this article covers. The practical risk for a candidate is real: buying a study guide, practice test or course for the wrong credential wastes money and time, and the content will not map to the ACAC exam.
The official name is the cleanest filter. Whenever you evaluate a resource, look for the full phrase "Council-certified Microbial Consultant" and the ACAC name, not just the three-letter abbreviation. Our companion pieces on what CMC means and what a CMC is cover the same ground from different angles.
Who Stands Behind This Credential
Three organizations matter, and it helps to keep their roles straight:
- ACAC (American Council for Accredited Certification): the issuer. Its CMC Certification Board reviews applications and grants certification.
- CESB (Council for Engineering and Scientific Specialty Boards): the accrediting body for the certification program itself.
- Kryterion, Inc.: the exam delivery partner, supporting testing-center and online video-proctored administration scheduled through ACAC.
This structure matters because it tells you where to verify facts. Fee schedules, application forms, handbooks and domain charts all live on ACAC's own pages, and that is the source you should trust when third-party prep sites disagree with each other.
What a Council-certified Microbial Consultant Actually Does
The title describes a person who can run the full arc of a microbial problem: understand the organisms involved, recognize the health implications, plan an investigation, collect defensible samples, interpret results, guide remediation and protect the people doing the work. ACAC requires candidates to demonstrate the ability to design, conduct and interpret sampling regimens, which is what separates this certification from a general awareness credential.
Typical work settings include environmental consulting firms, industrial hygiene practices, building-science and engineering firms, and restoration-adjacent consultancies. If you are researching openings, our CMC jobs page discusses where the credential tends to be relevant. We also do not quote salary numbers here, because no reliable salary survey specific to ACAC CMC holders has been verified; the CMC salary guide and the ROI analysis explain how to evaluate the return without borrowing figures from unrelated credentials.
The Six Exam Domains Behind the Name
The name "microbial consultant" is easier to grasp once you see what the exam objectives include. ACAC's formal domain chart, approved February 21, 2024, lists six domains. ACAC does not publish percentage weights for them, so no domain can honestly be called the "biggest." Treat all six as testable.
Domain 1: Scientific knowledge of biological agents
The foundation: what the organisms are, how they grow, and what conditions support them.
- Fungi, bacteria and related biological contaminants found in indoor environments
- Moisture, nutrients and growth conditions
- Bioaerosols and how biological material becomes airborne
Domain 2: Potential health effects and risks associated with exposure
Why the work matters: translating presence of organisms into plausible health concerns without overstating certainty.
- Exposure pathways and susceptible populations
- The limits of what sampling data can say about health outcomes
Domain 3: Principles of Microbial Investigation
How a consultant frames a problem before touching a sampler.
- Building and moisture history, observations and hypotheses
- Building-science reasoning about where contamination originates and travels
Domain 4: Principles of Microbial Sampling
The technical heart of the credential.
- Designing sampling regimens that answer a defined question
- Method selection, equipment use and calibration
- Interpreting results and recognizing data limitations
Domain 5: Principles of Microbial Remediation
What happens after the findings.
- Remediation scope, containment and documentation
- Post-remediation verification and how it relates to the original investigation
Domain 6: Health & Safety
Protecting workers and occupants during investigation and remediation.
- Respiratory protection concepts and respirator selection
- Hazard awareness for personnel on site
Exam Format at a Glance
| Feature | Council-certified Microbial Consultant exam |
|---|---|
| Issuer | ACAC, CMC Certification Board |
| Delivery | Computer-delivered; testing center or online video proctoring scheduled through ACAC |
| Questions | 120 multiple choice, at least four answer options each |
| Time | Three hours |
| Books and notes | Closed book |
| Passing score | 75%, set using the Modified Angoff method |
| Practical component | No separate practical assessment described |
| Results | Immediate electronic score, with results emailed |
A few logistics worth knowing: the handbook describes randomized question and answer order, and adaptive testing is not described. The split between scored and unscored questions is not published. Testing-center candidates need two government-issued IDs, including one with a photo. Online candidates need their own computer, an approved webcam, a private location, and an internet connection of at least 2 Mbps upload and download; phones and tablets are not permitted. ACAC's current Examinations page specifies arriving 15 minutes early, while the handbook says 30, so plan for the earlier-of-everything cushion. Calculator permission is unverified, so confirm it with ACAC before test day.
The passing score deserves its own clarity. The 75% threshold is the score a candidate must reach on the exam. It is a different thing from a pass rate, which describes how many candidates succeeded. Read more in our CMC passing score and pass rate articles. For context, ACAC's 2025 Exam Pass Ratio reports 94%, based on 16 passes from 17 attempts. That is a very small sample, it includes retakes and state-licensing-only candidates, and it is not first-attempt-only data, so read it as a snapshot rather than a prediction.
Who Qualifies to Use the Title
The credential is experience-gated, which is part of what the name signals. ACAC publishes three routes to eligibility, each combining education with documented microbial sampling or consulting experience:
- A related four-year postsecondary degree, or 30 qualifying college credits, plus four years of documented microbial sampling experience.
- A related two-year degree, or 15 qualifying credits, plus six years of documented experience.
- A high school diploma or GED plus eight years of consulting experience in microbial sampling.
Qualifying fields include microbiology, engineering, science, architecture and industrial hygiene. ACAC's FAQ defines qualifying coursework and excludes social sciences. The handbook says experience should come from Building Sciences, Microbiology and Microbial Risk Analysis, though that wording is guidance rather than a confirmed mandatory three-area rule.
The application package includes four project sheets, applicable transcripts and experience verification. ACAC does not require a preparation course or a minimum number of training hours. One honest caution: ACAC's current application page describes online forms, email verifications and unanimous board approval over roughly six months including the exam, while the handbook cites 90 days and notarized forms or employer affidavits. That conflict is unresolved, so check ACAC directly before you plan your timeline. Our CMC requirements and exam dates guides track the details.
Key Takeaway
Because the title is tied to documented sampling experience, your application clock often starts long before your study clock. Begin gathering project sheets, transcripts and verifiers early, and treat them as a parallel workstream to exam prep.
Fees, Validity and Renewal
| Item | Amount (USD) |
|---|---|
| Examination fee | $100 |
| Certification fee (includes $100 nonrefundable processing) | $400 |
| Total for initial two-year term | $500 |
| Retake | $100 |
| Renewal | $400 |
ACAC publishes no separate member and non-member fee schedule. Certification lasts two years. Current recertification procedures call for 40 recertification credits (RCs): 10 for continued field activity and 30 for professional development during the term, along with an attestation and retained evidence in case of audit. Note that other ACAC documents describe the requirement slightly differently (the handbook uses general 40-RC wording and a program page mentions 20 professional-development hours per year), so follow the current Recertification Procedures page. A fuller breakdown lives in our CMC certification cost guide.
CMC Versus Its Closest Relatives
ACAC administers related microbial credentials, and the domain chart document covers both the CMC and CMI examinations. Candidates often search "CMC vs CMI" for that reason. The key distinction to remember is that this site is about Council-certified Microbial Consultant only; do not assume a fact about a sibling credential carries over. Likewise, a licensing-only exam result does not itself confer CMC certification, which matters if your state requires an exam for licensure.
For a broader orientation to the credential family, see CMC certification and what CMC certification is.
Getting Started Without Wasting Time
Because the exam assumes comprehensive knowledge of ACAC's listed references, your study plan should start from the source material. The handbook lists, among others, the ACGIH Bioaerosols: Assessment and Control (first edition 1999 or second edition 2024), the AIHA Field Guide for the Determination of Biological Contaminants (second edition, 2005), ANSI/IICRC S500-2021, S520 in either its 2015 or 2024 edition, the OSHA Small Entity Compliance Guide for the Respiratory Protection Standard (2011), and NIOSH Respirator Selection Logic (2004). The handbook explicitly warns that its selected study-guide pages are examples, not an exhaustive prep list.
If you want a light sequencing idea tied to the domains, one reasonable approach is below. Adjust it to your own background, since a building scientist will move faster through Domain 3 than a microbiologist will.
Build the biology and health foundation
- Domains 1 and 2, anchoring terminology before technique
Work the method-heavy domains
- Domains 3 and 4, with attention to sampling design and data limits
Close with remediation and safety
- Domains 5 and 6, then timed mixed review
When you are ready to test yourself, use the CMC practice tests to check recall across all six domains, and pair them with the CMC study guide and the one-page cheat sheet for final review. If you want to gauge your readiness honestly, read how hard the CMC exam is. You can also explore a full set of practice questions aligned to the official objectives, and see our notes on CMC training options.
Frequently Asked Questions
It stands for Council-certified Microbial Consultant, a certification issued by the American Council for Accredited Certification (ACAC) through its CMC Certification Board.
No. Several unrelated credentials share the acronym. This article covers only the ACAC microbial consulting certification, so always check the certifying body and the full title before buying study materials.
The exam has 120 multiple-choice questions delivered over three hours, closed book. The passing score is 75%, set using the Modified Angoff method. No separate practical assessment is described.
The initial two-year term totals $500: a $100 examination fee plus a $400 certification fee that includes $100 nonrefundable processing. A retake is $100 and renewal is $400.
No mandatory preparation course or minimum training-hour requirement is published. What you do need is a qualifying education and documented microbial sampling experience combination, plus four project sheets, transcripts and experience verification.