7.3 Payer-specific rules: how payers differ (authorizations, unit caps, concurrent billing, case rates)

Last updated: July 23, 2026

Colorado Medicaid, TriCare, and every commercial plan each set their own rules for authorizations, start dates, covered codes, units, and documentation. Alpaca encodes most of these rules so claims come out formatted correctly — but knowing where payers differ helps you avoid the denials and start-date mistakes that new practices make most. Your region's specifics live in the payer pack for your area; this guide is the map.

The dimensions payers differ on

1. Authorization timing (the start-date rule)

The question that causes the most confusion: can I start before the auth is approved?

  • Colorado Medicaid and most commercial plans — you can start on or after your requested start date; the payer backdates the approval, so a pending auth doesn't have to stall care.

  • TriCare — you must wait for approval. TriCare does not backdate; sessions before approval generally can't be billed.

2. Covered codes and unit caps

Not every payer covers every code, and each caps units per authorization period (sometimes per day). Two examples worth knowing:

  • Colorado Medicaid does not pay for 97156 (parent/caregiver training) as a billable service — caregiver goals have to be addressed another way.

  • 2:1 services are requested differently by payer — in Colorado, without the 0373T code.

Watch the authorized units on each client's Insurance tab; billing beyond the cap won't be reimbursed.

3. Concurrent billing (BCBA + RBT overlap)

Supervision is a 97155 session run alongside an RBT's 97153, so the two overlap in time. Whether both can be billed for the same interval is payer-specific:

  • Most payers allow it.

  • TRICARE forbids simultaneous 97153 + 97155 — Alpaca carves out the overlapping interval automatically to keep the claim compliant.

4. How assessments are paid

  • Some payers pay assessments per unit like therapy.

  • Colorado Medicaid pays assessments as a case rate (a flat amount for the assessment, not per-unit), on an alternating high/lower cycle. This changes how you plan reassessments.

5. Documentation, EVV, and frequency limits

  • Medicaid requires Electronic Visit Verification (EVV) via Sandata — proof the clinician was physically present. A Medicaid claim won't submit until the visit is EVV-verified, so accurate recording and on-time note signing matter more than usual.

  • Medicaid also enforces assessment-frequency limits — duplicate 97151/97152 assessments within a year are blocked to prevent double-billing.

  • TriCare runs under the Autism Care Demonstration (ACD), which dictates assessment types, required outcome measures, and re-authorization cadence.

6. Rendering provider and billing entity

Payers differ on who appears on the claim — some want the supervising BCBA listed even when an RBT ran the session; others want the actual session clinician. Some payers are billed through Alpaca's billing entity rather than your clinic's. Alpaca configures this per payer; getting it wrong is a common denial cause, which is why it's automated.

7. Timely filing

Every payer sets a timely-filing deadline — a hard number of days from the date of service after which a claim is denied for good (Cigna ~90 days, Aetna ~120, TriCare ~365). A timely-filing denial can't be appealed, so Alpaca prioritizes at-risk claims — but late-signed notes are the usual cause of missing the window. Sign on time.

What to do

  • Identify which payers cover your current clients.

  • Read the payer pack for your region (Colorado Medicaid, TriCare West, …) before submitting treatment plans or scheduling — it has the specifics this overview only sketches.

  • For a dual-coverage client, submit to the payer that will actually authorize and reimburse (see the eligibility/COB guide).

  • When a payer rule is unclear, email support@alpacahealth.io before submitting — a pre-submission question is far cheaper than a denial.

Quick reference

  • Start date: CO Medicaid / commercial = start on/after requested date (backdated); TriCare = wait for approval.

  • CO Medicaid: no 97156, assessments are case rates, 2:1 without 0373T, TJ modifier applied.

  • TRICARE: no simultaneous 97153 + 97155 (auto-carved), ACD governs assessments/measures.

  • Medicaid: EVV (Sandata) required before a claim submits; assessment-frequency limits apply.

  • Timely filing deadlines are unappealable — sign notes on time.