Quick reference: U.S. credentialing authorities

How federal and state authorities interact

The CMS National Plan and Provider Enumeration System assigns a single 10-digit National Provider Identifier that follows a clinician across state moves and employer changes. The NPI is necessary for every Medicare and Medicaid claim, but it does not, by itself, confirm that the provider currently holds an active state license, that authorization is delegated to each state medical board under the Tenth Amendment. Browse PlainDoctor by state to see how providers register practice locations.

Why specialty board certification matters

Board certification by an American Board of Medical Specialties member board signals voluntary post-licensure examination and ongoing Maintenance of Certification cycles. It is not legally required to practice medicine, but health plans, hospital credentialing committees, and patients increasingly use it as a quality signal. View specialty-level data through PlainDoctor specialty pages showing certification rates by jurisdiction.

Reading disciplinary records responsibly

State medical board orders are public legal documents that describe the factual findings, conclusions of law, and disciplinary action taken. A single malpractice payment does not necessarily indicate poor practice, high-risk specialties (neurosurgery, obstetrics) have higher baseline payment rates than primary care. Patterns of multiple actions, license restrictions, or revocations are the meaningful signals to weigh. Read the PlainDoctor methodology for how disciplinary data integrates into provider profiles.

Step 1, What should you look for in a doctor?

Before searching for a doctor, clarify what type of provider you need. For routine checkups, preventive care, and managing common illnesses, a primary care physician (PCP) is the right starting point. PCPs include family medicine doctors, general internists, and pediatricians. If you have a specific condition or need a procedure, a specialist may be more appropriate, but many specialists require a referral from a PCP for insurance coverage purposes.

Consider practical factors early: geographic proximity to your home or workplace, whether the provider accepts your insurance plan, hospital affiliations (relevant if you might need hospitalization), and whether the practice is accepting new patients. These logistical factors eliminate many options quickly, so it's better to check them before investing time researching a specific provider.

Step 2, Search the NPI Registry

The National Plan and Provider Enumeration System (NPPES), maintained by the Centers for Medicare & Medicaid Services (CMS), is the most authoritative public database of U.S. healthcare providers. Every provider with a National Provider Identifier (NPI) appears in this registry. You can search it directly at the CMS NPI Registry, or use PlainDoctor's search which indexes the same data.

An NPI record includes the provider's full legal name, primary specialty taxonomy code (which identifies their specialty category), practice address, phone number, and the date their NPI was issued. Cross-referencing a provider's NPI confirms that the person is a real, federally registered healthcare provider, not just a name on a website.

Note that some providers hold multiple NPI numbers (individual NPI Type 1, and organizational NPI Type 2 for a practice entity). When searching for a doctor as an individual, filter for Type 1 NPIs.

Step 3, Understand Provider Credentials

Healthcare providers use a range of credential abbreviations after their names. Understanding what these mean helps you choose the right type of provider:

MD (Doctor of Medicine) - A fully licensed physician who completed four years of medical school at an allopathic institution, followed by residency training (3–7 years depending on specialty). MDs are licensed by state medical boards and can prescribe medication and perform surgery in their trained specialty.

DO (Doctor of Osteopathic Medicine) - A fully licensed physician who completed four years of osteopathic medical school. DOs have the same prescribing and surgical privileges as MDs and receive additional training in osteopathic manipulative medicine (OMM). Most patients will find no practical difference between care from an MD and a DO.

NP (Nurse Practitioner) - An advanced practice registered nurse (APRN) who has completed a master's or doctoral degree in nursing. NPs can diagnose conditions, order tests, and prescribe medications, though their scope of practice varies by state. Some states allow NPs to practice independently; others require physician supervision.

PA (Physician Assistant) - A nationally certified provider with a master's-level degree who works as part of a physician-led team. PAs can diagnose, treat, and prescribe, but their scope of practice is supervised by a licensed physician. The credential has recently been renamed "Physician Associate" by many professional organizations, though PA is still widely used.

Other common credentials: CNM (Certified Nurse-Midwife), CRNA (Certified Registered Nurse Anesthetist), CNS (Clinical Nurse Specialist), DPM (Doctor of Podiatric Medicine), OD (Doctor of Optometry), DDS/DMD (Dentist), DC (Doctor of Chiropractic), PhD/PsyD (Psychologist).

Step 4, Verify State Licensure

An NPI number confirms a provider is registered with CMS, but it does not confirm that their state license is active. A provider's state medical board license is the legal authorization to practice in that state. Licenses can be suspended, revoked, or placed on probation, and these actions are publicly documented.

Every state has a medical board that maintains a publicly searchable license database. For physicians, the Federation of State Medical Boards (FSMB) operates DocInfo.org, which aggregates license and disciplinary information from all 50 states. You can search by name and verify active license status, board actions, and malpractice reports submitted by insurers.

For nurse practitioners and physician assistants, check the relevant state nursing or PA board website directly. Most state health department websites have a license lookup tool accessible through their main portal.

Step 5, Check Board Certification

Board certification is voluntary and goes beyond basic licensure. A board-certified physician has passed comprehensive specialty exams administered by one of 24 member boards of the American Board of Medical Specialties (ABMS) or the American Osteopathic Association (AOA). Board certification indicates demonstrated expertise in a specialty area.

To verify ABMS certification, search at certificationmatters.org (free public lookup). For AOA-certified osteopathic physicians, check osteopathic.org. Enter the physician's name and state to confirm their certification status, specialty, and whether their certification is current (many certifications require periodic recertification exams).

Note that some physicians are board eligible but not yet certified, this typically means they have completed training but have not yet taken or passed the certification exam. It is common early in a career and does not necessarily indicate a problem.

Step 6, Evaluate the Practice and Ask Questions

Credentials verify that a provider is qualified. Choosing the right fit requires a few more steps:

Check hospital affiliations. Physicians are credentialed by each hospital where they have admitting privileges. If you need hospitalization, knowing which hospital your doctor is affiliated with matters, especially if you have a preferred facility or if a specific hospital has specialists you may need.

Review patient feedback cautiously. Online reviews can surface consistent patterns (very long wait times, communication issues) but are not statistically reliable for individual quality of care. One-star reviews are often outliers; patterns across many reviews are more informative. Healthgrades, Zocdoc, and Google reviews are common sources.

Ask about communication preferences. Many practices now offer secure patient portals (MyChart, Healow) for messaging, test results, and appointment scheduling. If direct communication with your provider matters to you, ask during the first visit whether the doctor or a staff member responds to portal messages.

Confirm coverage continuity. Ask whether the practice has coverage arrangements for after-hours or urgent needs. Large practices often have on-call physicians; solo practitioners may direct after-hours calls to an answering service or urgent care.

Use our specialty directory to find providers in specific medical fields, or browse by state to see providers in your area.

Frequently Asked Questions