Types of Medical Specialties Explained: From MD to Subspecialty

Curious about the types of medical specialties and the paths healthcare providers take? From Family Medicine to Pediatric Cardiology, the medical field is packed with fascinating opportunities. Let’s explore how doctors choose, train, and grow into experts in their specialties and subspecialties—making healthcare as tailored as possible.

KEY TAKEAWAYS:

Medical specialties allow doctors to focus on specific fields like Cardiology, Dermatology, or Pediatrics.
MDs and DOs differ slightly in training but share equal opportunities in all specialties.
Board certifications and taxonomy codes are essential for credentialing and billing in healthcare.
Subspecialties like Pediatric Cardiology or Rheumatology provide deeper expertise for specialized care.
Rotations during medical school help students explore different fields and choose their path.

What Exactly Are Medical Specialties?

When a medical provider enters the healthcare field, they have to make one major decision: what type of medicine they want to practice. This isn’t just about becoming a doctor but involves choosing a specific field to focus on. For instance, some healthcare providers choose physical therapy, occupational therapy, or speech therapy—fields that often work hand-in-hand. Others may dive into behavioral health, like psychiatrists, psychologists, or social workers.

But today, we’re zooming in on doctors—the MDs (Medical Doctors) and DOs (Doctors of Osteopathic Medicine). Whether you’ve heard these acronyms thrown around before or not, you’ll leave here understanding their differences and the massive range of specialties they can pursue.

MDs vs. DOs: What’s the Deal?

Both MDs and DOs are fully licensed physicians capable of diagnosing, treating, and prescribing. The big difference lies in where they study and their philosophies. Here’s the breakdown:

MDs (Medical Doctors): These folks attend allopathic medical schools and follow a traditional Western medicine approach. They focus on diagnosing and treating conditions primarily through medication, surgery, and technology.
DOs (Doctors of Osteopathic Medicine): DOs attend osteopathic medical schools, which offer the same education as MD programs but add an extra layer: osteopathic manipulative medicine (OMM). This hands-on approach is focused on treating the whole person—body, mind, and spirit—and incorporates techniques to address musculoskeletal imbalances (think chiropractor vibes but with a broader medical lens).

Both paths lead to the same residencies, the same board certifications, and ultimately the same level of expertise. It’s just a matter of philosophical preference when choosing their medical school. Cool, huh?

The Path to Specialization: From Residency to Board Certification

Once a medical student has finished four grueling years of medical school, it’s decision time: which residency program to apply for. Residencies are specialized training programs where doctors get hands-on experience in their chosen field. These last anywhere from 3 to 7 years, depending on the specialty.

Medical Rotations: Testing the Waters

In the last two years of medical school, students rotate through various specialties, like internal medicine, family medicine, pediatrics, and surgery. This helps them figure out what they love (and what they absolutely don’t). Think of it as medical speed-dating but with way more pressure.

Competitive Residency Matches

Residency programs are competitive. Students apply to programs across the nation, hoping to snag a spot in their dream specialty. They even have to plan for backup options in case they don’t get their first choice. It’s a tough world out there!

The American Board of Medical Specialties: 40 Specialties and Counting

Here’s where it gets official. Every specialty has its own board that governs the certification process. For example:

Family Medicine has its own board.
Internal Medicine has its own board.
Dermatology, Cardiology, Psychiatry… you name it, there’s a board for it.

These boards set the standards, administer the board exams, and ensure specialists maintain their certifications. And here’s a fun fact: board certification wasn’t always required. Back in the day, some doctors were “grandfathered” into practicing without having to take the boards. Not anymore! Now, every doctor has to take and pass their board exams, and many certifications require recertification every few years.

Subspecialties: Going Deeper Into the Field

If a doctor decides to take their expertise even further, they can pursue a subspecialty through a fellowship program. This is like doing a mini-residency but in a hyper-specific niche. Let’s break it down with an example:

A doctor completes a residency in Pediatrics and becomes board-certified.
They realize they’re passionate about Pediatric Cardiology.
To pursue this passion, they complete a fellowship in Pediatric Cardiology and take another board exam to become sub-board certified.

Now they’re not just a pediatrician—they’re a Pediatric Cardiologist, meaning they’ve gone even deeper into their field. And trust me, there are tons of subspecialties to choose from—about 90 in total!

A Quick Look at Specialties and Subspecialties

Let’s organize this in a simple table because who doesn’t love a clean visual? Here’s a glimpse into the possibilities:

Specialty	Subspecialty Options
Pediatrics	Pediatric Cardiology, Neuropediatrics
Internal Medicine	Cardiology, Gastroenterology, Nephrology
Family Medicine	Sports Medicine, Geriatrics
Surgery	Plastic Surgery, Neurosurgery

Source: American Board of Medical Specialties. (Definitely check them out if you want to geek out over more details!)

The Hidden World of Taxonomy Codes: What Are They and Why Do They Matter?

Taxonomy codes—those little-known but massively important details in the world of medical specialties. These codes are unique identifiers that classify a provider’s specialty and subspecialty for billing and credentialing purposes.

Here’s the deal:

Every doctor has a taxonomy code that’s tied to their specialty (like Family Medicine, Pediatrics, or Dermatology) or their subspecialty (like Pediatric Neurology or Cardiothoracic Surgery).
These codes are registered with their NPI (National Provider Identifier), so when they bill insurance companies, there’s no confusion about what type of care they’re authorized to provide.

For example:

A doctor practicing Internal Medicine has a taxonomy code for that specialty.
If they decide to pursue a subspecialty in Gastroenterology, they’ll get a different taxonomy code for that, reflecting their advanced training.

Here’s a table to make it crystal clear:

Specialty/Subspecialty	Taxonomy Code
Internal Medicine	207R00000X
Gastroenterology (Subspecialty)	207RG0100X
Pediatrics	208000000X
Pediatric Neurology	2084N0400X

Why does this matter?

Because insurance companies and billing systems rely on these codes to determine reimbursement rates, ensure accuracy in claims, and classify providers correctly. If the wrong taxonomy code is used, it can delay payments—or worse, result in a claim being denied.

Billing Processes: How Specialties and Subspecialties Affect Reimbursement

Billing in healthcare is complicated. Your specialty (or subspecialty) can directly impact how much you’re reimbursed for services. Why? Because reimbursement rates are often tied to the complexity of care provided.

Here’s a simplified breakdown:

General Specialties: Providers in general fields, like Family Medicine or Internal Medicine, often have lower reimbursement rates because they handle broader, less-specialized care. For example, a routine check-up or managing chronic conditions.
Subspecialties: Specialists like Cardiologists or Neurosurgeons often receive higher reimbursement rates because they’re performing highly technical, complex procedures.
Niche Subspecialties: And here’s where it gets interesting. If a doctor pursues an ultra-specialized subspecialty (like Pediatric Cardiac Surgery), they may become one of the only providers in their region for that service. This exclusivity can lead to significantly higher reimbursements—but also comes with a smaller pool of patients needing that level of expertise.

The Connection Between Billing and Credentialing

Credentialing specialists (aka the heroes behind the scenes) are the ones who ensure that a provider’s taxonomy codes, licenses, and certifications all align with their specialty. If you’re managing a medical group or contracting specialists, this process is critical. Why? Because it affects the following:

Insurance contracts: The taxonomy codes used dictate reimbursement rates, so contracts need to reflect the correct specialty/subspecialty.
Claim accuracy: Wrong taxonomy codes lead to rejected claims, delayed payments, and general headaches for providers and patients alike.

Medical Credentialing Process: What Every Provider Needs to Know

Switching Gears: Pursuing a Subspecialty Later in Your Career

Let’s say a doctor finishes their residency and works in a general specialty, like Internal Medicine, for a few years. One day, they decide, “You know what? I’d really love to specialize in Cardiology.” Can they make the switch? Absolutely.

Here’s how it works:

Identify the Subspecialty: Doctors typically pursue subspecialties in areas related to their current specialty. For example, an Internal Medicine physician can transition to Cardiology, but they can’t just jump into Orthopedic Surgery—it’s not related to their training.
Apply for a Fellowship: A fellowship is essentially a training program for subspecialties. These programs can last 1 to 3 years, depending on the field. During this time, the doctor hones their skills in their new niche.
Board Certification in the Subspecialty: Once the fellowship is complete, they take another board exam to become certified in their new subspecialty.
Update Credentials: This is where taxonomy codes come back into play. Their new subspecialty requires updated credentials and billing codes to reflect their advanced training.

Here’s an example timeline:

Residency: Internal Medicine (3 years)
Practice: General Internal Medicine (5 years)
Fellowship: Cardiology (3 years)
New Role: Board-certified Cardiologist!

Why Some Doctors Pursue Subspecialties Later

It’s not uncommon for doctors to pursue a subspecialty later in their careers. Here are some common reasons:

Passion for a Specific Field: They discover a niche area they’re deeply interested in—like becoming a Neuro-Oncologist after practicing as a general Neurologist.
Market Demand: If their region has a high demand for a certain specialty (but very few providers), pursuing a subspecialty can be a smart career move.
Personal Growth: Some doctors just love learning and want to expand their expertise.

What About Rare Subspecialties?

Here’s where it gets tricky. Some subspecialties are so rare that you may not find providers in every region. For example:

Neonatal Surgery: Specializing in surgery for newborns.
Medical Toxicology: Focusing on the effects of poisons and toxins.
Hyperbaric Medicine: Treating patients in pressurized chambers for conditions like decompression sickness.

In these cases, patients often need to travel across the country to find a specialist. This rarity also makes these providers incredibly valuable—and often well-compensated.

FAQs About Types of Medical Specialties

Let’s tackle some frequently asked questions about types of medical specialties, their subspecialties, and the fascinating journey healthcare providers take to get there. Whether you’re a curious patient, an aspiring medical student, or just someone fascinated by the complexities of healthcare, this FAQ section will break it all down in simple, easy-to-understand terms.

What is a medical specialty?

A medical specialty is a specific branch of medicine that doctors focus on after finishing medical school. It’s what allows doctors to develop expertise in a certain area of healthcare, like Cardiology, Pediatrics, or Family Medicine.

Doctors train for their specialty during their residency, which can last anywhere from 3 to 7 years, depending on the specialty. After that, they become board-certified in their chosen field by passing rigorous exams.

What’s the difference between MDs and DOs?

Great question! Both MDs (Medical Doctors) and DOs (Doctors of Osteopathic Medicine) are fully licensed physicians who can diagnose, treat, and prescribe medication. The difference lies in their training:

MDs attend allopathic medical schools and focus on traditional Western medicine.
DOs attend osteopathic medical schools, where they learn the same medical principles but also focus on treating the whole person—mind, body, and spirit. They’re also trained in osteopathic manipulative medicine (OMM), which involves hands-on techniques to address musculoskeletal imbalances.

Ultimately, both MDs and DOs can specialize in any field of medicine, and their education paths converge during residency.

How many medical specialties are there?

According to the American Board of Medical Specialties (ABMS), there are 40 official medical specialties. These specialties cover a wide range of fields, from Internal Medicine and Dermatology to Neurology and Orthopedic Surgery.

Beyond that, there are 90 recognized subspecialties, allowing doctors to dive even deeper into specific areas of care. For example:

A doctor specializing in Pediatrics might pursue a subspecialty in Pediatric Neurology.
An Internal Medicine physician could specialize further in Cardiology or Gastroenterology.

What is a subspecialty?

A subspecialty is an even more focused area within a medical specialty. Doctors train in a subspecialty through fellowship programs, which come after their residency.

For example:

A doctor might specialize in Family Medicine (general care for people of all ages) but decide to pursue a Sports Medicine fellowship.
A surgeon might train further to specialize in Pediatric Surgery or Cardiothoracic Surgery.

Subspecialties allow doctors to become true experts in a very specific field, providing highly specialized care for their patients.

How do doctors decide their specialty?

Doctors usually decide their specialty during medical school. In their final two years, they go through rotations in different fields (like Surgery, Pediatrics, and Psychiatry) to see what they enjoy most.

Once they decide, they apply for a residency program in that specialty. Sometimes doctors change their minds after starting practice, in which case they can return to training for a subspecialty or even switch specialties entirely (though this is rare).

What is board certification, and is it required?

Board certification is the process of becoming officially certified in a specialty or subspecialty by passing a rigorous exam.

While being board-certified wasn’t always required in the past (some older doctors were “grandfathered” in), it is now mandatory for all new doctors. Certification helps ensure that a provider has met the highest standards of knowledge and skill in their field.

Doctors also have to recertify every few years to maintain their credentials, depending on the requirements of their specialty’s governing board.

What is a taxonomy code? Why is it important?

A taxonomy code is a unique 10-character code assigned to every healthcare provider that identifies their specialty or subspecialty. For example:

An Internal Medicine doctor’s taxonomy code might be 207R00000X.
A Cardiologist (a subspecialist of Internal Medicine) would have a different code: 207RC0000X.

These codes are essential for credentialing and billing, as they ensure that insurance companies and healthcare systems classify doctors correctly for reimbursement. Using the wrong taxonomy code can lead to rejected claims or delayed payments.

Can a doctor change their specialty later in their career?

Yes! A doctor can pursue a new specialty or subspecialty later in their career. For example:

A general Internal Medicine doctor might decide to specialize in Rheumatology after practicing for a few years.
A Family Medicine doctor could choose to focus on Sports Medicine.

This process usually involves completing additional training (like a fellowship) and becoming board-certified in the new field.

Wrapping It All Up: The Fascinating World of Medical Specialties

We’ve covered a lot in this deep dive into types of medical specialties. From understanding the differences between MDs and DOs to breaking down residency programs, board certifications, and the intricate world of subspecialties, it’s clear that the journey to becoming a specialist—or subspecialist—is no walk in the park. And let’s not forget the behind-the-scenes role of taxonomy codes and billing, which ensure that providers are properly credentialed and reimbursed for their expertise.

Whether it’s a Family Medicine doctor staying in their general field or an Internal Medicine physician pursuing a fellowship in Cardiology years later, there’s no shortage of opportunities for healthcare providers to grow and specialize. And for patients? These specialties and subspecialties mean better, more tailored care—whether that’s a dermatologist treating stubborn skin conditions or a neonatal surgeon operating on newborns in life-or-death situations.

The world of medical specialties is vast, exciting, and constantly evolving. If you’re ever curious about what makes healthcare tick or want to explore your options as a patient or provider, start by checking out resources like the American Board of Medical Specialties. There’s so much out there to discover!

And with that, I’ll leave you to digest all this info. Got questions or topics you want to dive into further? Let me know in the comments, or share this knowledge with someone who’d find it fascinating! Until next time, keep learning and exploring.