Medical Billing Setup for New Practices: A 90-Day Playbook

Credentialing starts the moment a practice has a NPI, a Tax ID, and the providers' personal CAQH profiles. Wait too long and the cash flow consequences are severe.

The CAQH ProView profile must be 100% complete and re-attested every 120 days. Missing fields are a common reason an application is returned. Verify: licenses, DEA, malpractice insurance with carrier name and policy number, work history with no gaps over 30 days (if there are gaps, document them in writing), education with verifiable contact info, and hospital privileges where applicable.

Medicare enrollment uses Form CMS-855I (individual provider) or CMS-855B (group) submitted via PECOS. CMS's Program Integrity Manual (chapter 10, revised July 2026) sets Medicare contractor processing standards for a PECOS initial enrollment: 95% completed within 15 calendar days of receipt and 100% within 50 when no site visit, development or fingerprinting is needed, and 95% within 50 and 100% within 85 when one is. These are processing standards, not a promised effective date. By regulation the effective date is the later of the filing date of the application that is approved and the date you first furnish services at the location, and retrospective billing reaches back up to 30 days before the effective date (90 days after a Presidentially-declared disaster), and only where circumstances precluded enrolling in advance, so file before you see Medicare patients.

Medicaid enrollment is run by each state's Medicaid agency, so the clock is the state's own: ask the agency for its current processing time before you set an opening date.

Commercial payers (Aetna, BCBS, Cigna, UnitedHealthcare, Humana, regional payers) publish their own clocks, where they publish one. Cigna says medical credentialing typically takes 45 to 60 days once it has the application packet (Cigna guide); Humana's policy target is 30 calendar days from a complete application, though its behavioral health page says 60 to 90 days (Humana guide); Evernorth says up to 90 calendar days for individual providers; Aetna's join page gives no processing time for an individual clinician (Aetna guide). Each payer requires its own application, with overlapping but not identical document requirements. Submit all major payers in parallel, not sequentially.

The critical operational rule: do not see insured patients before the effective date for that payer. Whether a payer retro-dates is its own rule, so ask each one and do not count on it. Plan opening day around the slowest payer in your priority mix, or accept that some early visits will be cash-pay or write-offs.

Software decisions made in the first 60 days are hard to change later. The four core systems:

Practice Management (PM) and EHR. Decide whether to use an integrated PM/EHR (Athenahealth, eClinicalWorks, NextGen, Epic for larger groups, DrChrono for very small practices, Kareo/Tebra for sub-2-provider) or separate best-of-breed systems. Integration matters because a charge captured in the EHR must flow cleanly into PM as a claim — every disconnect adds rework.

Clearinghouse. Most PMs include or partner with a clearinghouse (Change Healthcare/Optum, Availity, Waystar, Trizetto). Clearinghouse fees are $0.25-$0.45 per claim; rejection rates and edit rules vary. The clearinghouse runs your claims through scrubbing rules before sending to payers.

Eligibility and prior auth tools. Real-time eligibility (270/271 transactions) is essential — it catches lapsed coverage and wrong plan IDs before the patient is seen. Many PMs have built-in eligibility; standalone tools are available if not.

Patient payment portal. Patient responsibility is 30-40% of collections in 2026. Without a patient payment portal, those dollars take 60-90 days longer to collect.

Fee schedule setup. Build your fee schedule from the current Medicare allowable for each code you bill — it is published and free — and set billed charges as a multiple of it, then adjust by payer based on contracted rates. The multiple is the practice's own decision; there is no published standard for it. Fee schedules must be loaded in PM before day one — billing at incorrect rates means underpayments go undetected.

Claim scrubbing rules. Configure scrubbing for the top 10 denial reasons in your specialty: missing modifier, NCCI bundling, incorrect POS, missing referral, prior auth not obtained, etc.

The five most expensive mistakes new practices consistently make:

1. Seeing patients before credentialing is complete. Cash-pay collections from a patient who thinks they have insurance is much harder after the visit than at check-in. If credentialing is delayed, either reschedule or bill the patient directly with full disclosure that their insurance is not yet in effect.

2. Undercoding due to inexperience. New providers often default to lower-level E/M codes (99213) when documentation supports 99214. The CY2026 national Medicare non-facility amounts for those two codes are $95.19 and $135.61 — a gap of $40.42 per visit that compounds across thousands of visits in year one (see the conversion factor tracker for the per-code figures and their source). AMA's 2021 E/M revisions made coding documentation-dependent, not time-dependent — a chart-prompt template can prevent systematic undercoding.

3. Skipping eligibility verification. New practices often "trust the insurance card" and skip the 270/271 transaction. Inactive coverage, a wrong plan ID and terminated benefits are among the largest front-end denial categories and among the cheapest to prevent — the transaction takes seconds and runs before the visit. No free primary source publishes a share-of-denials figure for it, so none is quoted here.

4. Failing to follow up on denied claims. A new practice's first denials arrive before anyone has built the workflow to work them, and unworked denials age into A/R and then into write-offs. The figures usually quoted here — a share of denials that are "appealable", an appeal success rate — are not published by any professional society and trace to vendor-sponsored content, so this page does not repeat them. What is checkable is the process: every denial coded to its CARC/RARC reason when the ERA posts, appealed inside that payer's own deadline, and counted by payer and reason so the practice's own overturn rate is measured rather than assumed.

5. Hiring internal billing staff in year one. A single new biller in months 1-6 of a practice has minimal claim volume to work — they are paid for idle capacity. Outsourced billing at 7-9% of collections (typical for sub-$1M practices) almost always beats internal staffing for year one. Reassess at month 12 once volume is established.

The biggest financial risk in year one is misjudging cash flow. The pattern is predictable but counterintuitive.

Months 1-2: Near-zero cash. Even with credentialing complete, claims submitted in month 1 typically pay 30-45 days later. Add a 5-7 day clean-claim cycle and the first deposits hit in week 6-8. Plan for two months of operating expenses with zero collections.

Months 3-4: Cash flow ramps. Collections begin to match charge volume. Days-in-A/R is typically 50-70 in this period (above the 35-45 day mature-practice target) because aged A/R is still small relative to total A/R.

Months 5-9: Working capital builds. Days-in-A/R stabilizes. Net collection rate becomes meaningful. This is when a new practice can first measure whether its billing is performing — clean claim rate, denial rate, payer mix vs. expected.

Months 10-12: Mature steady state. Collections should now match expected: net collection rate 92-96% of contracted, days-in-A/R 35-45, denial rate below 7%.

Cash reserve recommendation. New practices should open with 4-6 months of operating expenses in reserve to cover the credentialing-and-cash-flow ramp gap. Practices that open with less than 3 months of reserve frequently run into cash crises in months 2-4 that force expensive bridge financing or aggressive patient collections that damage early reputation.

Five KPIs to track from the first claim:

Clean claim rate (target: >95%). Percentage of claims accepted by payers without rework. Below 90% indicates scrubbing rules need tuning or charge entry has issues.

First-pass denial rate (target: <7%). Percentage of submitted claims denied on first adjudication. Track by reason: eligibility, authorization, coding, medical necessity, timely filing.

Days in A/R (target: <40 by month 6, <35 by month 12). Total A/R divided by average daily charges. The single best summary metric for revenue cycle health.

Net collection rate (target: >95%). Net collections divided by net charges (after contractual write-offs). Anything below 92% in year one indicates denial management gaps or payer-mix issues.

Charge lag (target: <2 business days). Days from date of service to charge entry. Long lag = late submissions = more timely-filing denials.

Report these monthly with the prior-month comparison and the 12-month trend. Practices that establish KPI cadence in year one rarely have major revenue cycle problems in years 2-3 because they catch issues at 5-7% deviation rather than at 20-30%.

For new practices, outsourcing usually wins year one. The math:

Outsourced cost (year one). Typical sub-$1M practice pays 7-9% of collections. On $400,000 in year-one collections, that is $28,000-$36,000 — proportional to revenue.

Internal cost (year one). A single biller costs $52,000-$68,000 base, $63,000-$87,000 loaded. Plus PM software, clearinghouse fees, training, and supervisor time. Total: $80,000-$105,000 — independent of revenue.

In months 1-6 when collections are low, internal costs eat 25-40% of collections. Outsourcing matches cost to revenue. Even after collections ramp in months 9-12, outsourcing remains competitive until annual collections cross roughly $1.5M.

Beyond year one: reassess at month 12 with a real fully loaded cost comparison. If practice volume is above 18,000-20,000 claims/year and growth is stable, internal billing becomes economically reasonable. Below that, outsourcing continues to beat on both cost and KPIs.

The rare case for hiring internal in year one: a practice opening in a niche specialty (behavioral health, ASC, oncology infusion) where billing-clinical integration matters and a tenured specialist biller is available to hire. Even then, the practice typically gets better year-one economics by outsourcing to a specialist vendor than by hiring. If outsourcing is the answer, outsourced medical billing services covers what a full-cycle vendor takes on and what it commits to, and medical billing for small practices is the version scoped for a 1–10 provider group.

Ten things to verify in any vendor SOW for a new practice:

1. Credentialing scope. Initial credentialing for new providers — included or extra? At what per-payer cost?

2. Provider enrollment timeline commitment. SLA for time-to-effective-date with each payer. Vendors who will not commit to timelines often have weak credentialing operations.

3. Eligibility verification workflow. Run before every appointment, or only on flagged accounts? 270/271 transactions or manual phone calls?

4. Charge entry SLA. Target charge lag — same-day, next-business-day, or 48-hour. Each day of charge lag is a day of cash flow loss.

5. Denial management staffing. Specialized appeal staff, or is denial work spread across general billers? Recovery rate target.

6. KPI reporting cadence. Daily dashboard, monthly review, quarterly business review. Sample report.

7. Pricing transparency. Percentage of net collections is clean. Per-claim pricing can be cheaper at scale but requires forecast volume. Watch for setup fees, statement fees, refund-processing fees.

8. Contract term and exit clause. Month-to-month or 30-90 day notice with no penalty. Avoid multi-year lock-ins.

9. Specialty fit. References from same-specialty practices. Mental health vs orthopedic vs primary care billing have very different operational rhythms.

10. Ramp commitment. Does the vendor have a structured 90-day onboarding playbook, or are you the first practice they have onboarded this quarter? Year-one performance depends on the ramp.