- MMB is ABPath's initial Medical Microbiology subspecialty certification for physicians, not an ASM or ASCP credential.
- The 2026 exam has 305 questions across six sections and 6 hours 10 minutes of active testing time.
- Bacteria dominates the blueprint at 49%, more than four times the next-largest domain.
- Passing requires a scaled score of 500, not a raw percentage-correct threshold.
What Is MMB Certification?
MMB is the site abbreviation used here for the American Board of Pathology's (ABPath) initial Certification in Pathology: Medical Microbiology subspecialty examination. On ABPath's own examination schedule, this credential is designated MB. It is a physician certification built on top of an existing primary board certification, not a bench-level laboratory credential and not the ASM ABMM examination or an ASCP-issued designation. If you're comparing options, it also isn't the same thing as a separate Clinical Microbiology focused practice designation offered elsewhere - those pathways have different sponsoring organizations, different eligibility rules, and different exams entirely.
For a broader orientation to the credential and how it fits into a pathology career, see What Is MMB Certification? and the companion explainer What Is MMB?. If you're still untangling the acronym itself, MMB Meaning and What Does MMB Stand For? walk through the naming convention in more detail.
Eligibility Requirements
MMB is not an entry-level exam. Candidates must already hold accepted primary certification - Anatomic Pathology/Clinical Pathology (AP/CP), AP alone, CP alone, or certification from another ABMS member board - before they can sit for the subspecialty exam. On top of that primary certification, ABPath requires 12 months of ACGME-accredited Medical Microbiology fellowship training, plus completion of the applicable ABPath medical education, licensure, and program-director verification requirements.
Because eligibility involves multiple moving pieces - training accreditation, primary board status, and program verification - it's worth mapping your own timeline against the official criteria well before registration opens. A full walkthrough of each requirement, along with common eligibility pitfalls, is available in MMB Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Exam Format & Structure
The MMB exam is a computer-based, single-best-answer multiple-choice test that incorporates written and practical material - meaning candidates should expect image-based and case-oriented items alongside straightforward recall questions. Testing happens in person at Pearson VUE Professional Centers; this is not a remotely proctored, at-home exam, so candidates need to plan travel and scheduling logistics accordingly.
For the 2026 cycle, the exam contains 305 questions across six sections, with 6 hours 10 minutes of active testing time. The total scheduled examination block is 8 hours 40 minutes, which includes instructions, a survey, and scheduled breaks - so candidates should budget for a full testing day, not just the active question time.
One notable feature: ABPath provides a Medical Microbiology Terminology reference during the examination itself. This is a narrow, built-in reference tool - it is not general open-book access, and candidates shouldn't plan to rely on outside material or broad lookup during testing.
Key Takeaway
Because the terminology reference covers only specific terms, candidates still need to memorize organism identification, mechanisms, and interpretive criteria cold - the reference tool won't substitute for content mastery.
For a deeper dive into exam-day logistics, section pacing, and what "practical material" actually looks like on screen, see How Hard Is the MMB Exam? Complete Difficulty Guide 2026. Scheduling specifics - including how far in advance to register for a Pearson VUE seat - are covered in MMB Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Exam Domains Breakdown
The 2026 blueprint carries an internal content specification date of April 10, 2026, and allocates content across seven domains. The distribution is heavily skewed toward one area, which should directly shape how you divide study time.
| Domain | Approximate Weight |
|---|---|
| Bacteria | 49% |
| Fungi | 13% |
| Viruses & Prions | 11% |
| Parasites | 11% |
| Traditional and Molecular Methods, NOS | 9% |
| Management & Informatics-Medical Microbiology | 5% |
| Management and Informatics-General | 2% |
Bacteria (49%)
This is the single largest domain by a wide margin - nearly half the entire exam. Candidates must be fluent in organism identification, resistance mechanisms, taxonomy changes, and clinical correlation across the full range of clinically relevant bacterial pathogens.
- Prioritize this domain first and revisit it most often in your review cycle
- Expect both classic identification questions and applied clinical scenarios
Fungi (13%)
The second-largest domain, covering mycology identification, emerging fungal pathogens, and antifungal susceptibility concepts that pathologists encounter in consultative practice.
- Morphologic identification remains central
- Don't neglect less common but clinically significant organisms
Viruses & Prions and Parasites (11% each)
These two domains are weighted evenly and together make up nearly a quarter of the exam. Viral diagnostics, molecular detection strategies, and parasite life cycles/identification are core content here.
- Treat these as equal-priority study blocks
- Expect overlap with molecular methods content
Traditional and Molecular Methods, NOS (9%)
Covers laboratory methodology spanning classic culture-based techniques through molecular diagnostics - a domain that ties directly into how findings from the other four domains are actually generated and interpreted.
Management & Informatics - Medical Microbiology (5%) and General (2%)
Together these smaller domains total just 7% of the exam but shouldn't be skipped entirely, since they cover practice management and informatics concepts specific to a microbiology laboratory setting.
For the complete official breakdown, including subtopics within each domain, see MMB Exam Domains 2026: Complete Guide to All 7 Content Areas. A condensed, high-yield reference of must-know facts across all domains is also available in MMB Cheat Sheet 2026: One-Page Review of Must-Know Facts.
Registration Cost and Fees
The 2026 initial application and examination fee for MMB is USD 2,100, which includes a USD 200 nonrefundable administrative fee. Candidates should factor this administrative portion into their planning, since it is not recoverable if you withdraw or reschedule outside the allowed window. Because testing is conducted in person at Pearson VUE Professional Centers rather than remotely, candidates should also budget for travel and time away from clinical duties on top of the exam fee itself.
A full breakdown of what's included in the fee, how it compares across the certification lifecycle, and what additional costs to anticipate is covered in MMB Certification Cost 2026: Complete Pricing Breakdown.
Passing Score and Pass Rate
MMB uses a scaled score of 500 as its passing standard - this is not equivalent to answering 50% of questions correctly. Scaled scoring accounts for item difficulty across the exam form, so candidates should not attempt to estimate their performance based on a simple percentage-correct calculation.
In 2025, 8 of 10 examinees passed, an 80% overall pass rate, and notably all 10 examinees that year were first-time test-takers. This is a small cohort, so the figure should be read as directional rather than a large-sample statistical benchmark.
For more context on how the scaled scoring model works and what it means for your preparation, see MMB Passing Score 2026: Exactly What You Need to Pass and MMB Pass Rate 2026: What the Data Shows.
Who Hires MMB-Certified Pathologists
MMB certification is typically pursued by pathologists who already hold AP/CP or AP or CP certification and want to formalize subspecialty expertise gained through an ACGME-accredited Medical Microbiology fellowship. This certification signals to hiring institutions - academic medical centers, hospital systems with dedicated clinical microbiology laboratories, and reference laboratories - that a pathologist has completed focused fellowship training and passed a rigorous, ABPath-administered subspecialty examination covering bacteria, fungi, viruses, parasites, and laboratory methodology.
Because the credential sits on top of primary board certification rather than replacing it, MMB-certified physicians often serve in roles that combine general pathology responsibilities with directorship or consultative duties in the microbiology lab. For a broader look at where this credential fits in the job market and what roles typically require or prefer it, see MMB Jobs and the return-on-investment discussion in Is the MMB Certification Worth It? Complete ROI Analysis 2026.
Building a Domain-Weighted Study Plan
Given that Bacteria alone accounts for roughly half the exam, an effective study plan should not spread time evenly across all seven domains. Instead, allocate study weeks proportional to blueprint weight, spending the most calendar time on bacterial identification, mechanisms, and clinical correlation before moving to the smaller domains.
Bacteria (49%)
- Work through organism identification and taxonomy systematically
- Focus extra time on resistance mechanisms and clinical correlation
Fungi (13%)
- Review morphologic identification and antifungal concepts
Viruses & Prions and Parasites (11% each)
- Pair these two domains since molecular detection concepts overlap
Methods and Management domains (9%, 5%, 2%)
- Cover laboratory methodology, then the smaller management/informatics topics
In the final stretch before your Pearson VUE appointment, cycle back through Bacteria at least once more given its outsized weight, and use practice questions to simulate the pacing of a 305-question, six-section exam. A more detailed week-by-week framework, including how to sequence practice tests, is available in MMB Study Guide 2026: How to Pass on Your First Attempt. You can also use our practice test platform to work through domain-weighted question sets that mirror the actual blueprint distribution.
Maintaining Certification After You Pass
Current ABPath certificates carry no fixed expiration date, but holding one is conditional on ongoing participation in Continuing Certification. This includes biennial PATHway reporting, maintaining professional standing, and demonstrating lifelong learning and improvement in medical practice.
The standard CME route requires 70 qualifying credits per two-year reporting period, with at least 80% of those credits related to your scope of practice. ABPath also permits approved training and research alternatives for physicians whose activities don't map neatly onto traditional CME credit.
Separately, ABPath CertLink offers a quarterly assessment format with a cumulative performance requirement of at least 60% over four years. This gives certified pathologists an ongoing, lower-stakes way to demonstrate continued knowledge rather than facing a single high-stakes recertification exam.
Key Takeaway
Passing the initial MMB exam is the entry point, not the finish line - budget time each reporting period for CME credits or CertLink participation to keep your certification active.
Frequently Asked Questions
No. MMB refers specifically to ABPath's Certification in Pathology: Medical Microbiology, a physician subspecialty certification. It is a distinct credential from the ASM ABMM examination, which serves a different candidate population and certifying body.
No. Testing is conducted in person at Pearson VUE Professional Centers. It is not remotely proctored at home, so candidates need to schedule an in-person testing appointment.
The passing standard is a scaled score of 500. This is not the same as answering 50% of questions correctly, since scaled scoring adjusts for item difficulty.
Bacteria, which makes up approximately 49% of the exam content - by far the largest single domain in the 2026 blueprint.
ABPath makes a Medical Microbiology Terminology reference available during the exam, but this is a narrow, built-in tool rather than general open-book access to outside materials.