Denial codes · Denial code
CO-170 on a dietitian's claim: the payer won't pay this code to an RD
By Javier Alvarez · Updated · 4 min read
| Official description | Payment is denied when performed/billed by this type of provider. |
|---|---|
| Group code | CO: do not bill the patient |
| Common remark codes | N95 (provider type may not bill this service), N570 |
| RD taxonomy | 133V00000X (Dietitian, Registered) or a 133V subspecialty |
| Medicare specialty code | 71, dietitians/nutritionists |
| Fix route | Corrected claim (recode or taxonomy); appeal only with policy support |
CO-170 is a denial about who billed, not what happened. The payer is fine with the patient's coverage and has no complaint about the visit; it simply does not pay that service when your kind of provider performs or bills it. For registered dietitians, that almost always means one of two things: a code outside what the plan pays RDs for, or a claim where the payer sees you as a different kind of provider than the one it credentialed.
What CO-170 means (official X12 wording)
The X12 Claim Adjustment Reason Code list defines CARC 170 as:
"Payment is denied when performed/billed by this type of provider."
Like several newer CARCs, its usage note points to the 835's Healthcare Policy Identification segment (loop 2110 REF), where the payer can name the policy. Its neighbor, CARC 171, adds "in this type of facility" for setting-specific restrictions.
The remark code most often paired with it is N95: "This provider type/provider specialty may not bill this service." You may also see N570, "Missing/incomplete/invalid credentialing data," when the problem is how you are enrolled rather than the code itself.
The usual causes on dietitian claims
1. Codes that plans don't pay RDs for
- E/M codes (99202-99215): these are billed by physicians and practitioners who can report evaluation and management. Medicare pays RDs for MNT (97802, 97803, 97804, G0270, G0271), and most commercial plans follow a similar pattern.
- Preventive counseling codes 99401-99404: some plans credential RDs for them, many do not. UnitedHealthcare's nonphysician E/M policy says RDs should not report 99401 and should use MNT codes instead. Details on 99401-99404.
- G0447 / G0473 (Medicare intensive behavioral therapy for obesity): billed by a primary care practitioner in a primary care setting, not under an RD's own NPI. See G0447.
2. The payer sees the wrong provider type
- Taxonomy. RDs typically carry taxonomy 133V00000X (Dietitian, Registered) or a 133V subspecialty in the NUCC code set. If your NPPES record, your credentialing file or the claim's taxonomy says something else (a counselor taxonomy, a group taxonomy that does not map to MNT), the payer's system may route the claim to the wrong provider type.
- Enrollment specialty. Medicare's specialty code for dietitians/nutritionists is 71 (Pub. 100-04, Ch. 4 §300.5). An MNT claim tied to an enrollment under another specialty will not match.
- Group vs rendering NPI. In a group, the RD's individual NPI must be in the rendering field (Box 24J). CMS's manual says the dietitian's identifier "that performed the service must be entered in on the claim form." If only the group NPI is present, or a physician's NPI is listed as rendering for a service the RD did, the provider-type logic breaks. See Type 1 vs Type 2 NPI.
3. Medicaid programs that do not recognize RDs as billing providers
Some state Medicaid programs and Medicaid managed care plans pay nutrition services only when billed by certain provider types, or only in certain settings. The program's provider manual is the only reliable answer; check it before you see the patient. Our pages on Medicaid nutrition counseling collect published examples.
4. Services billed under the RD that belong under someone else
The reverse happens too: a clinic bills an RD's MNT visit under the supervising physician's NPI, or a hospital outpatient department bills without the RD having reassigned benefits to it. CMS notes that hospitals can bill MNT only if the dietitian reassigns benefits; otherwise the RD bills under their own number.
How to fix a CO-170
- Identify the policy. Read the remark code and the policy reference; if missing, call and ask which provider types can bill the code.
- Recode if the visit was MNT. If what you documented was medical nutrition therapy, send a corrected claim (frequency code 7 with the original claim number) using 97802 or 97803 and the right units. Do not recode to something the note does not support.
- Fix enrollment data if that was the cause. Correct the taxonomy on the claim and in NPPES, confirm the payer's credentialing file lists you as an RD with the right specialty, then send a corrected claim.
- If the service belongs to another provider (for example incident-to under a physician), bill it correctly under that provider's rules. Incident-to has strict requirements; read Can dietitians bill incident-to? first.
- Appeal only with policy support. If the plan's published policy or your contract says RDs can bill the code, appeal with that page attached.
How to prevent CO-170
- Ask at credentialing which codes you are contracted for. Get the list of CPT/HCPCS codes the contract pays RDs, in writing.
- Default to MNT codes. For most RDs and most payers, 97802/97803 (and 97804 for groups) are the codes plans expect. Use anything else only when the contract explicitly includes it.
- Audit your NPPES taxonomy and your credentialing profiles (including CAQH) once a year so they agree. See CAQH ProView for dietitians.
- Map your NPIs for group practices: which NPI is rendering, which is billing, and which taxonomy goes with each, per payer.
If the payer says you, specifically, were not eligible on that date (a credentialing effective date issue rather than a provider-type rule), the code is usually CO-B7. For every other code, see the denial code lookup.