- PHLD(ABB) is awarded by the American Board of Bioanalysis, and the full credential requires both General Knowledge and Public Health Microbiology.
- The official fee schedule lists a USD 420 application fee and USD 355 per individual examination component.
- Start your application 16-20 weeks before the exam; supporting documents are normally due 8-10 weeks before.
- The 20-CE eligibility prerequisite is suspended pending CMS enforcement and is not currently active.
What This Credential Is (and Is Not)
Several unrelated credentials share the same four-letter acronym. This cheat sheet covers only one: the Public Health Laboratory Director (PHLD) credential, designated PHLD(ABB). It is offered through the American Association of Bioanalysts (AAB), and the certifying and examining body is the American Board of Bioanalysis (ABB). If you have seen exam dates, fees or pass rates attached to a different PHLD, none of that applies here.
The credential is aimed at laboratory professionals who direct or supervise testing at a high level and who have a strong public health or clinical microbiology background. For a plain-language orientation, see What Is PHLD? and What Does PHLD Stand For?. For the broader picture of the credential itself, start with PHLD Certification.
The Two-Component Structure
The most important structural fact is that the complete credential requires both of the following examinations:
| Component | What It Covers | Can It Stand In for the Whole Credential? |
|---|---|---|
| General Knowledge (laboratory director track) | Management, regulation, finance, safety and related director-level topics | No |
| Public Health Microbiology | Technical microbiology, epidemiology, immunology and quality topics | No |
Passing one component does not substitute for the whole credential. Plan your preparation around two distinct bodies of knowledge: a management and regulatory half, and a technical microbiology half. The PHLD Exam Domains guide walks through how the content areas map onto each half.
Eligibility Snapshot
ABB's eligibility standards, effective December 28, 2024, define three routes. Each is summarized below at a high level; confirm the details against the official eligibility page before applying.
- Route 1: a CLIA-qualified director.
- Route 2: a qualifying Ph.D. or Sc.D.
- Route 3: an accepted clinical or professional doctorate. This route additionally requires 16 hours of specified doctoral coursework or an approved relevant thesis/research project.
Requirements common to all routes
Every route requires the same academic and experience foundation.
- 32 acceptable semester hours of chemistry and biological science coursework.
- Four qualifying years of experience within the preceding ten years.
- Within those four years, two years directing or supervising high-complexity testing.
- Also within those four years, two years of specified laboratory training or experience that includes one year in public-health or clinical microbiology.
- Pathway-specific licensing and laboratory-acceptability conditions still apply.
Fees, Timing and Retake Rules
Official fee schedule
| Item | Amount (USD) |
|---|---|
| Application fee | 420 |
| Individual examination component | 355 |
| General Knowledge plus one technical discipline, same day | 525 |
One piece of arithmetic is worth knowing: the application fee plus the same-day General Knowledge and technical discipline fee adds up to USD 945. That is a simple subtotal, not an advertised package price, and it is not an all-in preparation budget. It leaves out study materials and any retake fees. The PHLD Certification Cost breakdown explains how to build a realistic budget around these official numbers.
Application timeline
- Begin the application 16-20 weeks before the examination you are targeting.
- Supporting documentation is normally due 8-10 weeks before the examination.
- ABB generally administers the examinations in spring and fall; check the current schedule in PHLD Exam Dates: Testing Windows, Deadlines & Scheduling.
Because the documentation requirements involve verifying coursework and experience, many candidates lose a testing window simply by starting late. Back-plan from the exam date, not from the day you feel ready.
Retake rules
- After an initial failure, the FAQ permits two retakes.
- To keep your file open, a retake must occur within the next two administrations or one year, whichever is longer.
- After three failures, you must wait two years and reapply with evidence of additional education or training.
Key Takeaway
Treat the first sitting as a real attempt, not a trial run. Three failures trigger a two-year wait plus a fresh application with new evidence of education or training. Build your study plan to be ready for the first date you book.
The Twelve Preparation Topics
The twelve topics below are unweighted preparation topics. They are not twelve official combined examination domains, and they are not an exhaustive statement of current examination coverage. Domains 1-4 come from the headings of AAB's General Knowledge for the Laboratory Director 2026 online-course listing. Domains 5-12 come from the eight published headings of AAB's Review Manual for Public Health Microbiology, 2012 edition. Use them as a map of what to study, not as a blueprint of how the exam is scored.
General Knowledge half (Domains 1-4)
Domain 1: CLIA '88
The regulatory backbone of laboratory director responsibility.
- Director qualifications and responsibilities under the amendments.
- Complexity categories and what high-complexity testing implies for oversight.
- Personnel, proficiency testing and inspection obligations.
Domain 2: Financial Laboratory Management and Employment Law
The business side of running a laboratory.
- Budgeting, cost analysis and test-menu decisions.
- Employment law fundamentals relevant to hiring, discipline and supervision.
Domain 3: General Laboratory Management
Day-to-day leadership and operational decisions.
- Staffing, workflow and performance oversight.
- Policies, procedures and documentation.
Domain 4: Laboratory Safety, OSHA, and Disaster Preparedness
Protecting staff and maintaining operations under stress.
- OSHA requirements as they apply to laboratory work.
- Emergency and disaster planning for continuity of testing.
Public Health Microbiology half (Domains 5-12)
| Domain | Topic | Focus for a Director-Level Candidate |
|---|---|---|
| 5 | Bacteriology | Identification, susceptibility concepts and clinical significance |
| 6 | Environmental Microbiology | Water, food and environmental sample testing in a public health context |
| 7 | Parasitology | Recognizing organisms and matching them to specimens and presentations |
| 8 | Mycology | Fungal identification and clinical relevance |
| 9 | Virology/Molecular Microbiology | Viral testing approaches and molecular methods |
| 10 | Epidemiology in the Community | Outbreak thinking, surveillance and population-level interpretation |
| 11 | Immunology of Infectious Diseases | Host response and serologic test interpretation |
| 12 | Quality Control/Quality Assurance | Monitoring, corrective action and assurance systems |
The public-health emphasis matters. Domains 6 and 10 in particular distinguish this credential from a purely clinical microbiology review. Expect to think about communities and environments, not just individual patient specimens. For a deeper domain-by-domain treatment, read PHLD Exam Domains 2026: Complete Guide to All 12 Content Areas.
Question Style and Format
ABB's item-writing guidance specifies four-option multiple-choice questions and favors application and scenario items. In practice, that shapes how you should prepare:
- Scenario over recall. Expect a situation (a regulatory question, a specimen result, a staffing or safety problem) followed by a question about the best action or interpretation.
- Four options, one best answer. Distractors are written to be plausible, so eliminate by principle, not by gut feeling.
- Director perspective. Even in the technical half, think like the person accountable for the laboratory's decisions, not only the bench technologist.
ABB's publicly accessible General Knowledge Content Outline appears in its Item Writer Guide and was accepted in June 2014. Its 70 questions and percentages are historical and are not treated as current or as the whole PHLD examination. Do not build your plan around those figures. To gauge how challenging the format feels in practice, see How Hard Is the PHLD Exam?, and to practice scenario-style items, use the PHLD practice tests.
What Has Not Been Verified
A trustworthy cheat sheet states its limits. The following were not verified in accessible issuer sources, so this article does not state them:
- Current question counts for each component.
- Current exam duration.
- The numeric passing standard.
- Published pass rates.
If you see a specific passing percentage or pass rate quoted elsewhere, confirm it with ABB before relying on it. For what is and is not publicly known, see PHLD Passing Score 2026 and PHLD Pass Rate 2026: What the Data Shows.
Key Takeaway
When a number is missing from official sources, the right move is to ask ABB after eligibility approval, not to adopt a figure from a forum. Your approved application is what unlocks the current weighted outlines.
Sequencing Your Review by Domain
A good plan follows the structure of the credential rather than generic habits. The timeline below is tied to the two-component design and to the application calendar. For a full approach, see the PHLD Study Guide.
Regulatory foundation (Domains 1 and 4)
- Begin with CLIA '88 because it frames director accountability for everything else.
- Pair it with safety, OSHA and disaster preparedness while the regulatory vocabulary is fresh.
Management and finance (Domains 2 and 3)
- Cover financial management, employment law and general management.
- Practice scenario items that ask for the best managerial action.
Organism-based microbiology (Domains 5-9)
- Work through bacteriology, environmental microbiology, parasitology, mycology and virology/molecular.
- Spend extra time on the areas furthest from your daily work.
Population and assurance topics (Domains 10-12)
- Study epidemiology in the community, immunology of infectious diseases and quality control/quality assurance.
- Use these as integrating topics that tie the technical content together.
If you are sitting General Knowledge and one technical discipline on the same day, make sure your final weeks include mixed practice across both halves so that switching between management and microbiology thinking does not cost you time on exam day.
After You Pass: Validity and Revalidation
- Initial certification is valid through December 31 of the award year.
- Annual revalidation is required.
- You must complete 24 acceptable CE contact hours per two-year PEER cycle.
Because the initial term ends on December 31 regardless of when you passed, the first renewal can arrive quickly. Track your CE contact hours from the start rather than reconstructing them later. If you are weighing whether the ongoing commitment pays off, read Is the PHLD Certification Worth It? and the PHLD Salary Guide for earnings context, and PHLD Jobs for where the credential is used.
Frequently Asked Questions
Yes. The complete credential requires both components, and neither one substitutes for the whole credential.
The official schedule lists a USD 420 application fee, USD 355 for an individual examination component, and USD 525 for General Knowledge plus one technical discipline on the same day. The USD 945 figure is only the arithmetic subtotal of application plus the same-day examination fee, not an advertised package.
Start the application 16-20 weeks before the examination. Supporting documentation is normally due 8-10 weeks before it, so late starters often miss their intended window.
After an initial failure, two retakes are permitted. To keep your file open, retake within the next two administrations or one year, whichever is longer. After three failures, you wait two years and reapply with evidence of additional education or training.
No. ABB explicitly suspends the 20-CE eligibility prerequisite pending CMS enforcement, so it is not an active prerequisite at this time.