CO-173: Service not ordered by a physician

The payer is telling you there is no valid physician order on file for what you billed. They see the service as not prescribed, so they treat it as non covered under the plan rules. On the back end, the claim hits edits that look for an ordering, supervising, or referring provider NPI, or for a linked authorization tied to a physician order. The payer then reduces the line as a contractual adjustment and removes that amount from patient responsibility.

In behavioral health, this often hits PHP or IOP per diem claims where the payer requires a physician order for the level of care. If the attending psychiatrist is not listed correctly as the ordering provider, or the plan expects a separate initial order note, the per diem lines can be denied with CO-173. For residential and detox, many commercial plans and Medicaid MCOs require a physician or qualified prescriber order before admission and for continued stay. If the record only has a therapist intake, or the H&P is late or unsigned, the payer may say the stay was never actually ordered by a physician and deny days under CO-173. With outpatient therapy, MAT, and OTP services, some plans want a physician or prescriber order for specific codes, such as neuropsych testing, PHP step down, or methadone maintenance. If the claim shows only the rendering clinician and the medical record lacks a dated, signed order, the payer can recoup large spans of treatment days with this code.

• Confirm the payer actually requires a physician or prescriber order for the billed level of care or code set.
• Check the chart for a clear, signed, and dated physician or qualified prescriber order that covers the disputed service dates.
• Verify the correct ordering or attending provider NPI, taxonomy, and name are present in the claim fields the payer uses for orders (for UB claims usually attending or other provider, for 1500 claims ordering or referring).
• If the order exists but the claim was missing or had wrong ordering data, submit a corrected claim with the proper provider information and any required modifiers.
• If the payer says there is no order and you truly have none for those dates, write off the CO-173 balance as contractual and review internal admission and concurrent review workflows.
• If an order exists and the payer still denies, file an appeal with the order document, H&P, treatment plan, and any authorization showing it was based on a physician order.

• Build admission and level of care workflows that require a signed physician or prescriber order before billing PHP, IOP, residential, or detox.
• Map payer specific rules in your EHR or billing system for when an ordering provider must be sent on the claim for behavioral services and which NPI field they use.
• Run claim edits that flag behavioral health lines with codes or revenue codes that require an order when no physician or prescriber is attached.
• Audit a sample of charts each month to confirm orders exist, are signed and dated, and match the billed dates and level of care.