- What Is MMB, Exactly?
- Who Grants the MMB Certification
- Who MMB Is For
- Exam Format and Structure
- The Seven MMB Content Domains
- Registration, Fees, and Testing Logistics
- How Passing Is Determined
- Keeping the Certificate Active
- Where MMB Fits Professionally
- Building a Domain-Aware Study Plan
- Frequently Asked Questions
- MMB is the American Board of Pathology's initial subspecialty certification in Medical Microbiology, distinct from lab-based or ASM credentials.
- The 2026 exam runs 305 questions across six content sections in 6 hours 10 minutes of active testing.
- Bacteria dominates the blueprint at 49% of content, far ahead of every other domain.
- The 2026 fee is USD 2,100, including a nonrefundable USD 200 administrative fee, paid for in-person Pearson VUE testing.
What Is MMB, Exactly?
MMB is the site abbreviation used here for the Certification in Pathology: Medical Microbiology, a subspecialty certification issued by the American Board of Pathology (ABPath). On ABPath's own examination schedule, the credential is referenced with the code MB. If you've landed on this page trying to sort out competing definitions of "MMB," it's worth saying plainly: this site is built around the ABPath physician subspecialty exam, not the ASM ABMM examination, not an ASCP laboratory credential, and not a separate Clinical Microbiology practice designation. Those are different programs, run by different organizations, with different eligibility rules, fees, and exam structures.
MMB certifies that a physician-pathologist has met ABPath's standards of knowledge and judgment in medical microbiology, layered on top of an already-completed primary certification. It is not an entry-level credential - it's a subspecialty stamp added after residency and fellowship training.
Who Grants the MMB Certification
The American Board of Pathology administers MMB as one of its subspecialty certifications, built on top of accepted primary certification. ABPath publishes an annual content specification and exam schedule for the credential; the current detailed content specification carries an internal date of April 10, 2026, and the schedule document is labeled for the 2026 cycle. If you want the full breakdown of how ABPath weights each content area, see the MMB Exam Domains 2026: Complete Guide to All 7 Content Areas.
Who MMB Is For
MMB is not a first certification. Eligibility requires one of the following as a prerequisite:
- Accepted primary certification in Anatomic Pathology/Clinical Pathology (AP/CP)
- Primary certification in AP alone or CP alone
- Certification by another ABMS member board
On top of that primary certification, candidates need 12 months of ACGME-accredited Medical Microbiology fellowship training, plus ABPath's applicable medical education, licensure, and program-director verification requirements. This is a meaningful commitment layered on years of prior training - not a weekend add-on. For the complete eligibility checklist, read MMB Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Key Takeaway
You cannot sit for MMB without prior AP/CP, AP, CP, or another ABMS board certification plus a full year of ACGME-accredited microbiology fellowship training. Confirm your fellowship's accreditation status early.
Exam Format and Structure
MMB is a computer-based, single-best-answer multiple-choice examination that also incorporates written/practical material - meaning some items rely on images, slides, or lab data rather than text alone. The 2026 schedule specifies:
- 305 questions spread across six sections
- 6 hours 10 minutes of active testing time
- 8 hours 40 minutes of total scheduled time, which includes instructions, a survey, and breaks
Testing happens in person at Pearson VUE Professional Centers. There is no remote-proctoring option for this exam - you'll need to plan travel and scheduling around an approved test center. ABPath also makes a Medical Microbiology Terminology reference available during the exam itself; this is a narrow, built-in reference tool, not general open-book access to outside materials.
Because the day is long and cognitively demanding, pacing matters as much as content mastery. For a breakdown of what makes this exam difficult beyond raw content volume, see How Hard Is the MMB Exam? Complete Difficulty Guide 2026.
The Seven MMB Content Domains
The 2026 blueprint allocates content across seven domains, and the distribution is heavily skewed toward one organism category. Understanding these weights should directly shape how you allocate 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 by far the largest domain and effectively the backbone of the exam. Candidates should expect deep coverage of bacterial identification, pathogenesis, antimicrobial susceptibility patterns, and clinically significant organism groups.
- Treat this as the domain that determines whether you pass, not a domain among equals
- Prioritize recurring review across every study block, not a single dedicated week
Fungi, Viruses & Prions, and Parasites (13% + 11% + 11%)
Together these three domains make up over a third of the exam. Each is distinct enough to require its own review pass - fungal identification and mycology-specific terminology, viral diagnostics and prion disease features, and parasite life cycles and diagnostic morphology.
- Don't lump these together just because each is individually smaller than Bacteria
- Combined, they rival Bacteria in total exam weight
Traditional and Molecular Methods, NOS (9%)
This section covers diagnostic methodology - both classical microbiology techniques and molecular testing approaches - separate from organism-specific content.
- Expect questions on test selection, interpretation, and limitations of methods
Management & Informatics - Medical Microbiology (5%) and General (2%)
These two smaller domains together make up 7% of the exam but are easy to under-prepare for because they feel administrative rather than clinical.
- Don't skip these entirely just because they're low-weighted - every point counts toward a scaled score
For a section-by-section walkthrough with more granular topic lists inside each domain, see MMB Exam Domains 2026: Complete Guide to All 7 Content Areas.
Registration, Fees, and Testing Logistics
The 2026 initial application/examination fee for MMB is USD 2,100, which includes a USD 200 nonrefundable administrative fee. Because the administrative portion is nonrefundable, candidates should confirm eligibility and fellowship documentation before submitting an application rather than after. Testing takes place in person at Pearson VUE Professional Centers - there is no at-home remote-proctoring pathway for this subspecialty exam, so scheduling should account for travel time and test-center availability near your exam window.
A full cost breakdown, including how the administrative fee interacts with the total, is covered in MMB Certification Cost 2026: Complete Pricing Breakdown. If you're planning around specific testing periods and deadlines, check MMB Exam Dates 2026: Testing Windows, Deadlines & Scheduling before locking in fellowship or work commitments.
How Passing Is Determined
MMB uses a scaled score, and the passing standard is a scaled score of 500. This is not the same as answering half the questions correctly - the scoring model accounts for question difficulty across the 305-item exam rather than treating every item as equally weighted toward a raw percentage. Candidates sometimes assume a "50% correct" heuristic, which is inaccurate for this exam.
In 2025, 8 of 10 examinees passed MMB, an 80% overall pass rate, and all 10 examinees that year were first-time test-takers. That's a small cohort, which is worth keeping in mind when interpreting the number - but it does indicate that well-prepared, first-time candidates make up the bulk of who sits for this exam. For more context on what that pass rate does and doesn't tell you, read MMB Pass Rate 2026: What the Data Shows, and for a full explanation of the scaled scoring model, see MMB Passing Score 2026: Exactly What You Need to Pass.
Keeping the Certificate Active
Current ABPath certificates, including MMB, have no fixed expiration date. However, they remain conditional on ongoing participation in Continuing Certification, which includes:
- Biennial PATHway reporting
- Maintaining professional standing
- Lifelong learning and improvement-in-practice activities
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. Approved training and research alternatives also exist for physicians whose activity doesn't map cleanly onto traditional CME. Separately, ABPath CertLink offers a quarterly assessment format with a cumulative performance requirement of at least 60% averaged over four years - an alternative to periodic high-stakes recertification exams.
Where MMB Fits Professionally
MMB sits downstream of AP/CP, AP, CP, or another ABMS board certification, plus fellowship training - which means the physicians pursuing it are typically already practicing pathologists narrowing into microbiology-focused clinical or laboratory-director roles. It signals a documented, ABPath-verified depth in bacterial, fungal, viral, and parasitic diagnostics beyond general pathology training, which matters for hospital systems and reference laboratories evaluating who should direct microbiology services. For a broader look at how the credential factors into hiring conversations, see MMB Jobs, and for a discussion of return on the time and cost investment, read Is the MMB Certification Worth It? Complete ROI Analysis 2026.
Building a Domain-Aware Study Plan
Because Bacteria alone accounts for roughly half the exam, a generic even-split study calendar wastes time. A domain-aware plan front-loads and repeatedly revisits bacteriology while still giving Fungi, Viruses & Prions, Parasites, and Methods dedicated blocks.
Bacteria foundations
- Build organism-by-organism review sheets covering identification and pathogenesis
- Interleave antimicrobial susceptibility concepts throughout, not as a single topic
Fungi and Parasites
- Focus on diagnostic morphology and life cycles
- Use image-based practice since the exam includes practical material
Viruses & Prions plus Methods
- Cover viral diagnostics and prion disease features
- Review traditional and molecular testing methods and their limitations
Management & Informatics domains
- Don't skip the smaller 5% and 2% domains - review lab management and informatics basics
Full-length review, weighted toward Bacteria
- Run timed practice covering all 305-question, six-section format
- Revisit Bacteria repeatedly given its 49% share
For a step-by-step preparation framework built around this exact blueprint, see MMB Study Guide 2026: How to Pass on Your First Attempt, and for a condensed reference during final review, try the MMB Cheat Sheet 2026: One-Page Review of Must-Know Facts. You can also run full-length, timed practice sets modeled on the six-section structure through MMB Exam Prep's practice tests to get comfortable with pacing before test day.
Frequently Asked Questions
No. MMB here refers to the American Board of Pathology's Certification in Pathology: Medical Microbiology, a physician subspecialty certification. It is a separate program from the ASM ABMM examination, an ASCP laboratory credential, or a Clinical Microbiology practice designation.
The 2026 schedule includes 305 questions across six sections, with 6 hours 10 minutes of active testing time and 8 hours 40 minutes of total scheduled time including instructions, a survey, and breaks.
No. Testing is conducted in person at Pearson VUE Professional Centers; there is no remote-proctoring option for this exam.
A scaled score of 500 is required to pass. This is not equivalent to answering 50% of questions correctly - it reflects a scaled scoring model applied across the 305-item exam.
Current ABPath certificates have no fixed expiration date, but they remain conditional on ongoing Continuing Certification requirements, including biennial PATHway reporting, professional standing, and lifelong learning activities such as CME or CertLink participation.