Top 12 Common Types of Medical Billing

Medicare billing covers claims for beneficiaries enrolled in the federal Medicare program. Part A covers inpatient hospital, skilled nursing, hospice, and some home health services; Part B covers physician services, outpatient care, and durable medical equipment; Part C is Medicare Advantage, administered by private plans; and Part D covers outpatient prescription drugs. Traditional Medicare Part B claims are processed by Medicare Administrative Contractors, and coverage is governed by national coverage determinations and jurisdiction-specific local coverage determinations. Payment is calculated from relative value units multiplied by the annual conversion factor. Beginning in 2026, CMS applies two separate conversion factors, one for qualifying alternative payment model participants and one for all other clinicians, alongside a new efficiency adjustment to work RVUs for many non-time-based services. Medicare Advantage plans add their own prior authorization and network rules on top of Medicare coverage.

Medicaid billing covers claims for the joint federal and state program serving low-income and eligible populations. Because each state administers its own Medicaid program, covered benefits, provider enrollment rules, billing formats, prior authorization requirements, and timely filing limits vary from state to state. Most Medicaid enrollees are now covered through managed care organizations, so the practice must identify the correct plan, not only the state program, before submitting. Medicaid is generally the payer of last resort, which makes coordination of benefits and correct primary payer sequencing essential. Retroactive eligibility and monthly plan changes make eligibility verification on the exact date of service non-negotiable.

Commercial insurance billing covers claims to private carriers and employer-sponsored plans, including HMO, PPO, EPO, POS, and high-deductible plans paired with health savings accounts. Reimbursement is set by negotiated contract rather than a published government fee schedule, so payment accuracy depends on contract management as much as on coding. Self-funded employer plans administered by a third-party administrator behave differently from fully insured plans even when they carry the same network logo, because plan documents, appeal rights, and applicable regulation differ. High-deductible plans also shift a large share of the balance to the patient, which makes accurate up-front estimates part of the billing process rather than an afterthought.

Workers compensation billing covers treatment for work-related injuries and illnesses and is governed by state workers compensation law rather than health insurance law. Claims are billed to the employer insurance carrier or a third-party administrator, priced against a state fee schedule, and often require a claim number, date of injury, employer information, and adjuster details before they will process. Workers compensation typically involves no patient cost sharing but heavy documentation: injury causation statements, work status reports, treatment authorization, and periodic progress reporting. Missing authorization or an incorrect claim number is one of the most common reasons these claims sit unpaid for months.

Auto insurance billing covers treatment after motor vehicle accidents and is paid under personal injury protection, medical payments coverage, or a third-party liability settlement, depending on the state and the policy. No-fault states pay the injured party's own carrier regardless of who caused the accident. No-fault billing is deadline-driven and state-specific. New York, for example, operates an Article 51 no-fault framework with a strict submission window, and missing it forfeits payment entirely. Auto claims also require the claim number, adjuster contact, accident date, and assignment of benefits, and frequently involve attorney liens on third-party liability cases.

TRICARE billing covers active-duty service members, retirees, and their families, administered through regional contractors with their own referral, authorization, and network rules that differ from both Medicare and commercial plans. Veterans Affairs community care billing covers veterans treated outside VA facilities under approved referrals. Both programs are authorization-driven. A community care claim without a valid referral or authorization number, or one billed outside the approved episode of care, is denied regardless of medical necessity, so tracking the approval document is as important as coding the encounter.

Self-pay billing covers uninsured patients, non-covered services, cosmetic and elective procedures, direct primary care arrangements, and cash-pay models. There is no payer adjudication, so the entire balance is patient responsibility from the first statement. Self-pay is increasingly regulated rather than informal. Good faith estimate requirements under the No Surprises Act, state price transparency rules, and consumer collection statutes all shape how uninsured patients must be quoted, billed, and pursued. A published self-pay rate schedule, documented discount policy, and consistent payment plan terms reduce both disputes and compliance exposure.