The medical billing process, step by step

What the medical billing process is

The medical billing process is the sequence of steps that turns a patient visit into payment: registering the patient, verifying insurance, coding the visit, entering charges, checking and submitting the claim, posting what the payer pays, working denials, billing the patient for their share and reporting on the results. Most of the steps happen after the visit, but the most expensive mistakes are made before it.

Every step depends on the one before it. A wrong date of birth at registration becomes an eligibility rejection at submission. A missing authorization becomes a denial a month later. That’s why fixing billing problems usually means looking upstream from where the problem shows up.

1. Patient registration

Billing starts when the appointment is made. The front desk captures the patient’s legal name, date of birth, address, phone number and insurance details, ideally with a scan of the front and back of the insurance card and a photo ID.

Small errors here are some of the most common causes of rejected claims. A nickname instead of a legal name, a transposed digit in the member ID, or the wrong subscriber listed on a dependent’s plan will all stop a claim. Ask returning patients to confirm their insurance at every visit, not only at the first one, because coverage changes more often than patients mention.

2. Insurance eligibility and benefits verification

Before the visit, someone checks that the coverage is active, the provider is in network, and the service is covered. Good verification also captures the copay, deductible remaining, coinsurance and any requirement for a referral or prior authorization.

Most of this can be done electronically through the payer portal or the practice management system. The time to do it is a day or two before the appointment, so there’s still time to fix a problem or get an authorization. Our guide to insurance eligibility verification covers what to check and when.

3. The visit and documentation

The provider sees the patient and documents the encounter. Documentation isn’t a billing step on paper, but it decides what can be billed. A code is only as good as the note behind it, and payers that audit a claim look at the note, not the code.

Notes should be signed promptly. Unsigned or incomplete notes are one of the quiet reasons charges sit unbilled for days.

4. Medical coding

The visit is translated into standard codes. CPT and HCPCS codes describe what was done, ICD-10-CM codes describe why, and modifiers add context such as a separate service on the same day or a bilateral procedure. The diagnosis has to support the procedure, or the claim will be denied for medical necessity.

In some practices providers pick their own codes in the EHR. In others a certified coder codes from the chart. Either way, someone should review coding patterns regularly, because both undercoding and overcoding cost money. Our medical coding service covers chart review and coding audits.

5. Charge entry

Codes, units, fees, the rendering and billing provider, the place of service and the date of service are entered into the billing system, or flow across from the EHR. This is where the practice’s fee schedule is applied.

The key control at this step is charge reconciliation: matching the day’s appointments against the charges entered, so that no visit goes unbilled. Missed charges never generate a denial. They simply never become revenue.

6. Claim scrubbing

Before submission, the claim is checked against coding edits and payer-specific rules. A scrubber, built into the billing system or the clearinghouse, flags problems such as a missing modifier, a diagnosis that doesn’t match the procedure, an invalid NPI or a date outside the coverage period.

Scrubbing is cheap and denials are expensive. Every error caught here is a claim that doesn’t have to be reworked later.

7. Claim submission

Clean claims are sent electronically through a clearinghouse in the standard 837 format, either 837P for professional claims or 837I for institutional claims. The clearinghouse runs its own checks and sends back acknowledgments.

A claim that fails at the clearinghouse is a rejection. It never reached the payer, so it won’t appear in denial reports, and it has to be corrected and resent. Someone needs to work the rejection queue every day. The difference is explained in our article on claim rejections vs denials.

Submission also has a deadline. Every payer sets a timely filing limit, and a claim sent after it can be denied with no right to appeal. Medicare allows 12 months from the date of service. Commercial and Medicaid limits vary, so check each payer contract.

8. Payer adjudication

The payer reviews the claim against the member’s coverage, the contract with the provider and its own policies. It decides to pay in full, pay in part, deny, or ask for more information such as medical records.

Turnaround varies by payer and by state prompt-pay rules. A claim that hasn’t been paid or denied within the payer’s usual window needs a status check, not more waiting.

9. Payment posting

Payments arrive with an electronic remittance advice (the 835 ERA) or a paper EOB. Posting records the payment, the contractual adjustment, any patient responsibility and any denial against each line of the claim.

Posting is also the best place to catch underpayments. If the allowed amount on the remittance doesn’t match the contracted rate, the difference is money the payer owes you. Many practices post the payment and move on without checking.

10. Denial management and appeals

Denied lines are sorted by reason, corrected and resubmitted, or appealed with supporting documentation. The reason codes on the remittance tell you where to start, and our guide to claim denial codes explains the common ones.

Two habits separate strong denial management from weak:

• Speed. Appeals have deadlines. A denial that sits for six weeks may already be past the window.
• Root cause. Every denial is tracked to the step that caused it, so the fix happens at the front desk or in coding, not only in the appeal.

11. Patient billing and collections

Once insurance has paid, the remaining balance goes to the patient as a statement. Clear statements, online payment options and a consistent follow-up schedule all improve how much is collected. Collecting copays and known balances at the time of the visit is easier still, which is why accurate eligibility checks at step two matter so much.

12. Reporting and follow-up

The last step closes the loop. Monthly reporting should show days in A/R, the share of A/R over 90 days, net collection rate, clean claim rate and denial rate by reason. Those numbers tell you which step in this list needs attention. Our article on revenue cycle KPIs explains how to calculate each one.

Aging reports also drive follow-up. Any claim still open past the payer’s normal turnaround should be called on, and anything over 90 days needs a specific plan.

Where the medical billing process usually breaks

• Front end. Registration errors and skipped eligibility checks cause many of the rejections and denials practices see.
• Handoffs. Unsigned notes, charges never entered, and rejections nobody owns.
• Follow-up. Claims that go quiet and are only noticed after the filing or appeal deadline has passed.

None of these are complicated to fix. They need clear ownership and a daily routine.

See how your own process is performing

If you’re not sure which step is costing you money, the claims data will show it. Our free A/R audit reviews your recent claims, finds where they’re getting stuck, and shows what can still be recovered. You keep the findings whether or not you work with us.