Which Medical Procedures Require Prior Authorization? A Breakdown for 6 Key Specialties

A procedure your practice assumed was covered can still get denied if it required prior authorization and nobody checked. The rules are not consistent across specialties, payors, or even procedure types within the same specialty. Here is what actually requires prior auth across six of the highest-burden specialties, and what does not.

Specialty Prior Authorization at a Glance

Before going specialty by specialty, here is the quick reference. Use this table to confirm whether your specialty’s highest-volume procedures are likely to need prior auth before you schedule them.

Disclaimer: The information in this article is for general educational purposes only and does not constitute legal, financial, or compliance advice. Billing codes, payor rules, and regulatory requirements change frequently. Verify current requirements with your payor, your compliance officer, or a certified billing professional before making changes to your billing practices.

Facts and Figures for Specialty Prior Authorization

• Orthopedics, oncology, and cardiology consistently carry the highest prior auth burden due to high-cost procedures and imaging
• Dermatology and ophthalmology have specialty-specific triggers most general billing guidance misses entirely
• MRI and other advanced imaging almost always require prior auth, regardless of the ordering specialty
• Prior auth requirements change yearly and by payor, so a procedure that did not need authorization last year may need it now
• Tracking requirements by specialty, not just by payor, is the only way to stay ahead of denials

Let’s explore each specialty one by one and understand their prior auth needs.

Orthopedics: The Heaviest Prior Auth Burden in Outpatient Care

Prior authorization challenges in orthopedic practices are consistently among the worst in outpatient medicine.^³ Joint replacements, spinal procedures, and advanced imaging almost always require authorization, and the documentation standard is high.

• Joint replacement (hip, knee, shoulder) requires documented conservative treatment failure before most payors approve
• MRI for back, knee, or shoulder pain frequently requires prior auth, especially for Medicare Advantage plans
• Extended physical therapy beyond the initial visit count often needs authorization to continue
• Spinal fusion and decompression surgery carry some of the strictest documentation requirements in any specialty

Documentation requirements at this level are exactly the kind of administrative load that benefits from dedicated process management. See how proper prior authorization management reduces that burden.

Dermatology: Where Insurance Complexity Catches Practices Off Guard

Prior authorization challenges in dermatology practices are less obvious than in surgical specialties because most routine visits do not require it. The insurance complexity in dermatology prior authorization shows up specifically around biologics and certain procedures, not general dermatology visits.

• Biologic medications for psoriasis and eczema (Dupixent, Humira, and similar) almost always require prior auth and step therapy documentation
• Mohs micrographic surgery sometimes requires authorization depending on payor and lesion characteristics
• Cosmetic-adjacent procedures with a medical justification (certain excisions, scar revisions) frequently get flagged for medical necessity review
• Routine skin checks, biopsies, and standard excisions typically do not require prior authorization

Ophthalmology: Injections and Imaging Are the Trigger Points

Prior authorization challenges in ophthalmology cluster around a small number of high-cost treatments rather than routine eye care. Annual exams and standard diagnostic testing rarely need authorization.

• Anti-VEGF injections for macular degeneration (Eylea, Lucentis, Avastin) almost always require prior auth and ongoing reauthorization
• Certain cataract procedures with premium lens upgrades may trigger medical necessity review
• Advanced imaging like OCT for specific diagnoses can require authorization depending on payor policy
• Routine vision exams and standard cataract surgery typically do not require prior auth

Oncology: Speed Matters More Than Almost Any Other Specialty

Oncology prior authorization is unique because delays have a direct clinical cost. Chemotherapy regimens and biologic cancer drugs typically require authorization before the first infusion, and most payors offer expedited review given the urgency.

• Chemotherapy and biologic infusions require prior auth in nearly all cases, with most payors offering 24 to 48 hour expedited review
• PET scans for staging or treatment monitoring almost always require authorization
• Genetic and molecular testing tied to treatment decisions frequently requires separate authorization from the treatment itself

Cardiology: High-Cost Diagnostics Drive the Requirement

Cardiology prior authorization requirements are almost entirely procedural and diagnostic, not tied to office visits. The triggers are consistent across most payors.

• Cardiac catheterization and electrophysiology studies require prior auth from nearly every commercial payor
• Echocardiograms and stress tests increasingly require authorization, particularly for Medicare Advantage plans
• Pacemaker and implantable device procedures require extensive documentation of medical necessity before approval

Radiology: Advanced Imaging Almost Always Requires Authorization

Radiology prior authorization is the most consistent requirement across every specialty on this list, because the trigger is the imaging modality itself rather than the ordering physician’s specialty.

• MRI, CT, and PET scans require prior auth from nearly every commercial and Medicare Advantage payor
• Nuclear imaging studies face some of the strictest documentation requirements of any diagnostic category

MRI specifically:

Prior authorization for MRI is required by most payors regardless of which specialty ordered it. But does Medicare require prior authorization for MRI? Traditional Medicare generally does not, but Medicare Advantage plans frequently do, which creates confusion for practices treating mixed Medicare populations.^²

Cardiovascular Surgery: High-Stakes Procedures Mean High Scrutiny

Cardiovascular surgery prior authorization requirements are among the strictest in any specialty, driven by the cost and risk profile of the procedures involved. Payors require extensive documentation before approving anything beyond emergency intervention.

• Coronary artery bypass grafting (CABG) requires documented evidence of failed or contraindicated less invasive treatment, along with current cardiac imaging
• Valve replacement and repair procedures, whether surgical or transcatheter (TAVR), require multidisciplinary evaluation documentation in most payor policies
• Vascular surgery including aneurysm repair and bypass procedures typically requires imaging confirmation of severity before approval
• Stent placement outside of an emergency cardiac event almost always requires prior auth, while emergency placements are typically authorized retroactively

Emergency cardiovascular procedures are the one major exception across this specialty. Most payors process retroactive authorization for emergent, life-threatening cases, but elective and planned procedures face the full prior auth review process described above.

ENT and Otolaryngology: Where Pediatric and Adult Rules Diverge

ENT prior authorization requirements differ significantly depending on patient age and procedure type, which makes this specialty easy to get wrong if your team applies one standard rule across all cases.

• Tonsillectomy and adenoidectomy in adults frequently requires prior auth, while the same procedure in pediatric patients is often exempt or fast-tracked under separate payor criteria
• Sinus surgery (functional endoscopic sinus surgery) requires documented failure of conservative treatment, typically a minimum trial period of medical management before surgical approval
• Cochlear implants require some of the most extensive documentation in the specialty, including audiology test results, trial hearing aid outcomes, and candidacy evaluation from a specialist
• Surgical treatment for obstructive sleep apnea, including procedures beyond CPAP, generally requires a sleep study confirming diagnosis and severity before authorization

The age-based distinction in this specialty is the detail most practices miss. A procedure that sails through prior auth for a child can require a completely different documentation pathway for an adult, even when the surgical technique itself is identical.

Why Specialty Prior Authorization Rules Keep Changing

Specialty prior authorization requirements are not static. Payors adjust their prior auth lists annually, and a procedure that did not require authorization last year can require it this year with no notice beyond a policy update buried in a provider bulletin.^¹

The most reliable way to stay current is a quarterly review of payor policy updates for your top five highest-volume procedures, cross-checked against your most common payors. Waiting to find out through a denial is the most expensive way to learn a requirement changed.

For a broader look at the administrative strain this creates, see A3’s breakdown of the top challenges providers face with prior authorization.

Getting Prior Authorization Right Across Every Specialty

Tracking prior auth requirements across multiple specialties and payors is exactly the kind of work that falls through the cracks without dedicated staff. A3’s Prior Authorization Services manage the full process for practices across every specialty listed above, including submission, tracking, and appeals. Contact A3 for a free practice audit to see where your current prior auth process is creating delays.

Frequently Asked Questions

What is the difference between prior authorization and precertification?

The terms are largely interchangeable in practice, though some payors use them to mean slightly different things. Prior authorization typically refers to approval required before a service is rendered. Precertification sometimes refers specifically to inpatient admissions or planned procedures requiring advance notice. Always check the specific payor’s terminology in their provider manual, since usage varies.

Does behavioral health require prior authorization?

Yes, and often more aggressively than physical health specialties. Inpatient psychiatric admissions almost always require authorization before admission or within 24 to 48 hours of an emergency admission. Intensive outpatient programs and partial hospitalization programs typically require ongoing authorization renewed every few weeks, with the payor reviewing progress notes to approve continued treatment.

Do physical therapy visits need prior authorization?

Initial physical therapy evaluations generally do not require prior auth, but most payors cap the number of visits allowed before authorization is needed to continue treatment. The visit threshold varies by payor, commonly somewhere between 6 and 12 visits, after which documentation showing functional improvement is required to extend the authorization.

Does home health care require prior authorization?

Most Medicare Advantage and commercial payors require prior authorization for home health services, including skilled nursing visits and home-based physical or occupational therapy. Traditional Medicare has historically required less upfront authorization for home health, though this has been shifting as more home health is delivered through Medicare Advantage plans with stricter authorization requirements.

Is prior authorization required for a colonoscopy?

Routine screening colonoscopies typically do not require prior authorization under most commercial and Medicare plans, since preventive screening is broadly covered. Diagnostic colonoscopies ordered due to symptoms, and any colonoscopy that turns therapeutic with a polypectomy or biopsy, may face different coverage rules depending on the payor, though authorization specifically is less common in gastroenterology than in surgical specialties.

Do spinal injections for pain management need prior authorization?

Yes, in nearly all cases. Epidural steroid injections, facet joint injections, and nerve blocks for chronic pain almost universally require prior authorization, along with documentation of conservative treatment attempts. Implantable pain devices, such as spinal cord stimulators, require an even more extensive authorization process including a trial period before permanent implantation is approved.

Do oncology drugs require prior authorization?

Yes, almost universally. Chemotherapy agents and biologic cancer treatments require prior authorization from nearly every commercial and Medicare Advantage payor. Most payors recognize the clinical urgency and offer expedited review, typically within 24 to 48 hours, but the authorization step itself is rarely skipped regardless of urgency.

Does Medicare require prior authorization for MRI?

Traditional Medicare (Parts A and B) generally does not require prior authorization for MRI in most circumstances.^² Medicare Advantage plans, which are administered by private insurers, frequently do require it. This distinction causes confusion for practices that see both traditional Medicare and Medicare Advantage patients, since the same procedure can have different authorization requirements depending on which plan the patient holds.