TRICARE East vs. West: Billing Dos and Don'ts
Last updated: July 23, 2026
TRICARE splits into two regions, each run by a different contractor: Humana Military (East) and TriWest Healthcare Alliance (West). The Autism Care Demonstration (ACD) rules that govern most of what you can and can't bill are set DoD-wide and apply identically in both regions. What actually differs by region is who you submit to, which portal you use, and how fast they pay. This guide covers both.
Region at a Glance
TRICARE East | TRICARE West | |
|---|---|---|
Contractor | Humana Military | TriWest Healthcare Alliance |
Claims submission | Humana Military provider portal | TriWest provider portal (XPressClaim for lower-volume submitters) |
Timely filing | 365 days from date of service | 365 days from date of service (TriWest recommends filing within 30 days) |
Claims payment SLA | 98% paid within 30 days, 100% within 90 days | Not publicly published — confirm current SLA with TriWest or your RCM lead |
Appeals deadline | 90 days from the EOB | 90 days from the EOB (same TRICARE-wide rule) |
Note: Which contractor holds a client depends on where they're stationed/live, not where you practice — check the client's Insurance tab before assuming a rule applies.
Dos and Don'ts (apply to both regions — these are ACD policy, not contractor-specific)
Do:
Confirm the assessment (97151) authorization before scheduling. It's capped at 16 units (4 hours) within a 14-day window; unused units expire — they don't roll over.
Keep ABA and any other therapy (OT/PT/ST) sessions sequential, never overlapping. Same-day is fine; same clock-hour is not.
Verify every technician billing under you holds an active RBT, ABAT, or BCAT credential (or accepted state certification) — TRICARE checks this at the technician level.
Complete the ACD Annual Training Module on schedule. Missing it triggers a 10% penalty against all your claims until you're compliant.
Don't:
Bill 97153 and 97155 for overlapping time on the same client. TRICARE pays the higher-rate code and denies the other. (Exception: 97153 to the beneficiary and 97156 to the family can overlap only if delivered in separate locations by separate rendering providers — document both distinctly.)
Schedule or deliver a session before the authorization is approved. TRICARE does not backdate, unlike Colorado Medicaid and most commercial plans (see Care Readiness).
Let a 97151 authorization run past its 14-day window assuming you can still bill it — those units are gone.
Assume a login, portal habit, or claims quirk from one region carries over to the other. Confirm the contractor before you submit.
When Something Doesn't Match This Guide
If a TRICARE claim denies for a reason not covered here, or a cap/authorization number you see doesn't match what's above, check the client's Insurance tab first, then follow the SOP: Responding to Payer-Specific Billing Inquiries rather than guessing.
Quick Reference
East = Humana Military. West = TriWest Healthcare Alliance.
Core ACD rules (concurrent-billing ban, RBT/ABAT/BCAT credentialing, 97151 cap) are identical in both regions.
What differs by region: claims portal, contacts, and payment-processing speed.
Both regions: 365-day timely filing, no backdating, 90-day appeal window.
97151 capped at 16 units per 14-day window — use it or lose it.
ABA + OT/PT/ST must be sequential, never overlapping, for any payer under the ACD.