Different denials, different paths.
Surgery, MRI, medication, Medicare, prior auth, behavioral health. Each denial category has its own playbook. Find yours below.
Surgery denials
Surgical denials are issued before the procedure (prior authorization) or after (claim denial). Both have appeal paths. The strategy depends on which.
MRI and imaging denials
MRI, CT, PET, and other imaging denials are almost always issued at the prior-auth stage. They move fast, and so should the appeal.
Medication and prescription denials
Drug denials happen at the pharmacy benefit (PBM) layer, separate from the medical benefit. They include non-formulary drugs, GLP-1s, specialty injectables, brand-name vs. generic, and prior-auth-required medications.
Medicare denials
Medicare denials follow a federally-defined 5-level appeal process. Most beneficiaries stop at level 1. The higher levels, particularly the Independent Review Entity and ALJ, reverse a meaningful share of cases.
Prior authorization denials
Most 'denials' people receive are actually prior-authorization refusals, issued before care is delivered. The legal framework, timeline, and leverage are different from post-service claim denials.
Experimental or investigational denials
Carriers commonly deny coverage by labeling a treatment 'experimental' or 'investigational', a designation that bypasses the usual medical-necessity analysis. These denials are appealable, and many reverse when peer-reviewed evidence, compendia listings, or clinical-trial data are presented.
Mental health parity denials
The federal Mental Health Parity and Addiction Equity Act (MHPAEA) requires plans to apply no more restrictive treatment limitations to mental health and substance-use disorder benefits than to comparable medical/surgical benefits. Many denials violate parity, often unintentionally, and these violations are a powerful reversal lever.
Out-of-network emergency denials
The federal No Surprises Act (NSA), effective 2022, prohibits balance billing and most out-of-network cost-sharing for emergency services regardless of facility or provider network status. Denials and balance bills that violate the NSA are appealable, and providers face federal independent dispute resolution (IDR) rather than billing the patient.
Infertility and IVF denials
Infertility coverage varies dramatically by state and by plan. Roughly 20 states have some form of infertility coverage mandate, and several specifically mandate IVF. Denials in mandate states are often appealable on statutory grounds even when the plan's general benefit language excludes the service.
Gender-affirming care denials
Gender-affirming care denials may implicate the federal Affordable Care Act's Section 1557 anti-discrimination provisions and the WPATH Standards of Care (SOC 8) clinical framework. Coverage rules vary significantly by state and plan type, but appeals grounded in clinical guidelines and federal nondiscrimination law have a strong reversal track record.
Transplant and immunosuppressant denials
Solid-organ transplant patients depend on continuous immunosuppressive therapy to prevent rejection. UNOS/OPTN guidelines establish that immunosuppressant regimens generally cannot be switched without significant clinical risk. Denials of transplant evaluation, listing, surgery, or maintenance immunosuppression are among the most clinically urgent appeals.
Residential and level-of-care denials
Behavioral health and substance-use disorder denials often turn on level-of-care decisions, residential vs. partial hospitalization vs. intensive outpatient. Carriers frequently deny residential placement using internal criteria that have been ruled inadequate in landmark litigation, including Wit v. United Behavioral Health.
Air ambulance balance billing
Air ambulance denials turn on two distinct questions: whether the air transport itself was medically necessary versus ground transport, and whether the balance bill is even legal. The federal No Surprises Act bars balance billing for air ambulance regardless of network, but it pointedly does NOT cover ground ambulance, so the medical-necessity-of-flight argument is the heart of most air-transport appeals.
Step therapy override denials
Step therapy (also called 'fail-first') requires patients to try a plan-preferred medication and demonstrate failure or intolerance before the plan will cover the prescribed drug. Federal and many state laws require plans to allow exception requests when the step is clinically inappropriate.
Inpatient rehabilitation denials
Inpatient rehabilitation facility (IRF) stays are denied at admission or cut short mid-stay, usually on the argument that a lower level of care such as a skilled nursing facility would do. The appeal turns on the medical record showing why intensive, physician-supervised rehabilitation is required.
Skilled nursing facility denials
Skilled nursing facility (SNF) coverage is denied at admission or, more often, ended mid-stay with a Notice of Medicare Non-Coverage. The clock on these denials is measured in hours, and the appeal runs through the Quality Improvement Organization, not the plan.
Inpatient hospital stay denials
Hospital stays are denied as 'not medically necessary at the inpatient level', downgraded to observation, or cut off after a set number of days. The bill can be large and the patient often learns of the denial only after discharge.
IVIG and immunoglobulin denials
Intravenous and subcutaneous immunoglobulin (IVIG, SCIG) is expensive, infused repeatedly, and reviewed against a short list of accepted diagnoses. Denials say 'not medically necessary' or 'experimental' for the specific condition, or move the drug to a different benefit or site of care.
Biologic and infusion therapy denials
Biologics such as adalimumab, infliximab, vedolizumab, ustekinumab, and rituximab are denied at prior authorization for step-therapy, missing labs, or diagnosis mismatch, and later for site of care or dose escalation. The appeal is a documentation exercise against the plan's own criteria.
Physical therapy denials
Physical, occupational, and speech therapy are denied after a visit cap, when the plan decides progress has stopped, or when it labels care 'maintenance'. Denials are small per visit and large in total, and the maintenance argument is often wrong.
ABA therapy denials
Applied behavior analysis for autism is denied for hours, for age, for 'lack of progress', or as 'educational, not medical'. The appeal rests on the treatment plan, the assessment, and the coverage rules that apply to the plan.
Bariatric surgery denials
Sleeve gastrectomy, gastric bypass, and revision surgery are denied for unmet criteria far more often than for medical reasons: BMI history, a supervised weight-loss program, a psychological evaluation, or nutrition counseling missing from the file.
Breast reconstruction denials
Reconstruction after mastectomy, symmetry procedures on the other breast, revisions, and prostheses are denied as 'cosmetic' or 'not medically necessary'. A federal law decides most of these cases.
CPAP and medical equipment denials
CPAP and BiPAP machines, oxygen, power wheelchairs, hospital beds, and other durable medical equipment are denied for missing documentation, unmet usage requirements, or supplier problems. The rules are specific and the fix is usually paperwork.