Medicare from zero

Medicare is the best place to learn billing because its rules are published. Fee schedules, coverage policies, appeal rights: all federal, all public, all the same in every state. Learn Medicare well and commercial payers, which copy Medicare's structures and then complicate them, become tractable. Learn commercial payers first and you will feel like the ground keeps moving.

The parts, quickly

• Part A covers hospital, skilled nursing, hospice, and some home health. Institutional claims go out on the UB-04 form. Small practices rarely touch Part A directly.
• Part B covers physician and outpatient services: office visits, lab, imaging, durable equipment, preventive care. These claims go out on the CMS-1500, which descends from the paper form every older biller grew up on. This is your bread and butter.
• Part C, Medicare Advantage, replaces Parts A and B with a private plan.
• Part D is drug coverage, billed by pharmacies, not by you.

In 2026, the standard Part B premium is $202.90 a month and the annual Part B deductible is $283, after which the beneficiary pays 20 percent coinsurance for most services. You do not need those numbers memorized, because they reset every year and the January update is part of your annual rhythm. You do need the 80/20 shape in your bones: for a participating provider, Medicare pays 80 percent of the approved amount and the patient owes 20 percent, and a participating provider accepts the approved amount as payment in full and cannot bill the patient for the difference.

If you are building this business on the way out of a corporate job, this is also the system you will shop your own way into, and leaving corporate benefits behind prices that half of the decision.

Work the numbers once. Allowed amount eighty dollars. Medicare pays sixty-four. Patient owes sixteen. If the patient has a Medigap supplement or Medicaid, the sixteen crosses over to the other payer automatically in many cases, and your software posts both payments. That crossover machinery is why clean Medicare eligibility data matters so much.

The Advantage wrinkle

Here is the beginner trap. Roughly 35 million beneficiaries, about 55 percent of the eligible population, are now in Medicare Advantage rather than Original Medicare. Their card says "Medicare" on it somewhere. Their claims do not go to Medicare. They go to a private insurer with its own payer ID, network rules, prior authorization requirements, and claim edits.

The practical consequences: in Original Medicare you verify Part A and Part B effective dates and move on. In Advantage you verify the plan, the network status of your provider, whether the service needs authorization, and the plan's own rules, which differ by county and by plan. Advantage plans also process appeals under plan procedures, not Medicare's five-level chain, though the plan is subject to Medicare appeal timelines.

The card, the numbers, the identifiers

Every claim you touch carries identifiers, and beginners lose more money to identifiers than to anything else:

• MBI, the Medicare Beneficiary Identifier, is the eleven-character number on the red-white-and-blue card. It replaced the Social Security-based number.
• NPI, the ten-digit National Provider Identifier, identifies the rendering provider and the billing group. A claim with a wrong or missing NPI rejects before a human ever sees it.
• PTAN is the provider's Medicare transaction number from enrollment; practices have these on file, and you rarely handle one directly, but you will see the term.

Eligibility verification is where all of this gets checked. Original Medicare eligibility can be verified through your Medicare Administrative Contractor's portal or through the practice's software; the MAC for a practice depends on its state and claim type. Verify before the visit when possible, not after the denial.

One more concept and this lesson is complete: the Medicare Physician Fee Schedule sets the approved amount for every Part B service, adjusted geographically, using relative value units and a dollar conversion factor. As the biller you will not calculate it. You will live inside it: when a practice's revenue depends on which codes get billed and how often, the fee schedule is the map of where the money is.