Denial code

CO-150 denial code: payer says records do not support the level of service

CO-150 is a claim adjustment reason code that says the payer deems the information submitted does not support this level of service. In practice the payer has reviewed the claim or the chart and paid a lower level, or no level at all. The fix starts with the note, not the claim form.

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Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026

CO-150 at a glance

Code typeCARC, level of service not supported

DescriptorPayer deems the information submitted does not support this level of service.

X12 start date10/31/2002 (last modified 09/30/2007)

X12 usage noteNone given; read the group code on the remit

Remark codesNone assigned by X12; Medicare uses M25, M26, N163, N661

Medicare E/M ruleLevel by MDM or time since 01/01/2023 (manual ch. 12, 30.6.1)

Fix pathScore the note, appeal if it holds, correct the template if not

In short: CO-150 means the payer decided the claim and records do not support the level billed, which is usually a downcoded visit. Score the note yourself by medical decision making or time, then appeal with the note if it holds up, or correct the template if it does not. Medicare tells you to ask for review within 120 days.

What does CO-150 mean?

X12 defines claim adjustment reason code (CARC) 150 as: "Payer deems the information submitted does not support this level of service." The list gives a start date of 10/31/2002 and a last-modified date of 09/30/2007. Reviewed October 26, 2026.

X12 gives no usage note for 150, so read the group code on the remittance advice. The code is about the level, such as which of five office visit codes or which emergency department level. The payer is not saying the visit did not happen. It is saying the record does not back the intensity you billed, and the line is usually paid at a lower level.

X12 words four sibling codes the same way. CARC 151 is about the number or frequency of services (see CO-151), 152 about the length of service, 153 about the dosage and 154 about the day's supply. Match the wording before you pick the response.

What does Medicare say about choosing the level?

Chapter 12, section 30.6.1 of the Medicare Claims Processing Manual says that as of January 1, 2023, practitioners pick the visit level for most E/M families by the level of medical decision making or by time. For some visit types, such as emergency department visits and critical care, the CPT codes allow only one of the two. History and exam must still be performed as the code descriptor requires, but they no longer set the level.

The same section sets the test a reviewer applies. It calls medical necessity the overarching criterion for payment, says it is not appropriate to bill a higher level when a lower one is warranted, and says the volume of documentation should not be the primary influence on the level. When time is used, the full time must be completed, and the CPT midpoint rule does not apply.

For emergency department levels see CPT 99283, CPT 99284 and CPT 99285. For office visits see CPT 99214.

Which remark codes come with CO-150?

X12 assigns no remark code to CARC 150. Medicare uses these remittance advice remark codes for the same finding.

RARC	X12 wording (short)	Reading
M25	The information furnished does not substantiate the need for this level of service.	The notice asks you to request review within 120 days of the notice date if you disagree.
M26	Same opening sentence.	A refund rule: any amount collected from the patient for the level must be refunded within 30 days of the notice.
N163	Medical record does not support code billed per the code definition.	The note fails the code's own definition. Start date 02/28/2003.
N661	Documentation does not support that the services rendered were medically necessary.	A necessity finding, not only a level finding. Start date 07/15/2013.

M26 cites section 1824(I) of the Social Security Act and 42 CFR 411.408, and says physicians who knowingly and willfully fail to refund may face civil monetary penalties or exclusion.

How do you answer a CO-150?

Find the changed line

Compare the billed level with the paid level on the remit. Note the group code and any remark.

Score the note yourself

Rate it by decision making or by time under the CPT E/M guidelines. Do not score by length. Write down which element drives your level.

Sort the cause

The note may support the level and the payer is wrong, the note may omit what the provider did, or the level may have been over-coded.

Appeal a supported level

Send the full note, a one-page statement of the decision making or the time, and the claim. For Medicare, M25 says to ask for review within 120 days of the notice (redetermination).

Accept an unsupported level

Adjust the difference as the group code directs and feed the finding back to the provider and the template.

Refund if you collected

If the copay or coinsurance was taken at the higher level, check the payer's refund rule. M26 sets 30 days for Medicare.

Documentation requests are a separate path: see CO-252.

How does CO-150 read on the remittance?

X12 gives no group code for CO-150. On the line it is the payer saying the note does not support the level billed. Medicare uses remarks such as M25, M26, N163 or N661. Chapter 12 section 30.6.1 sets the level by medical decision making or time since 2023, so compare the code billed in item 24D or FL 44 with the note on those two measures.

A simplified remittance line with the group code, claim adjustment reason code, adjustment amount and remark code marked — Simplified, not a real 835. Read the group code, the CARC and the remark together on the same line.

Example: made-up amounts, illustrative only

A level 5 visit returns CO-150 for $75.00, the difference to level 4.

CheckThe note against MDM or time

ActIf it supports level 5, appeal with the note. If not, accept the reduction.

Where does CO-150 show up?

High-volume levels draw it most. That means emergency medicine billing for the upper emergency levels, hospitalist billing for subsequent-day notes and internal medicine billing for the mid and upper office levels. A claim paid at a lower level and flagged as not medically necessary may also carry CO-50. If these denials keep coming back, our denial management team can work them.

CO-151 Information does not support frequency of services CO-50 Not deemed a medical necessity by the payer CO-252 Attachment or documentation required

Sources

We check every rule, code and deadline against the official source. See our editorial policy.

FAQ

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01How do I appeal CO-150 downcoding denials?

Score the note by decision making or time first. If it supports the billed level, appeal with the full note, a short statement naming the element that drives the level, and the claim. Use the payer's appeal deadline; Medicare's M25 notice sets 120 days from the notice date.

02What does CO-150 mean?

X12 words CARC 150 as: payer deems the information submitted does not support this level of service. The visit is not disputed. The payer found the claim and records do not justify the intensity billed and usually pays a lower level. The group code shows who owes the difference.

03How is CO-150 different from CO-151?

CARC 150 is about the level of a service, such as a visit level. CARC 151 is about the number or frequency of services. Read the X12 wording on the remit, then pick the response: re-score a note for 150, or check counts and dates for 151.

04How does Medicare choose an E/M level since 2023?

Chapter 12 section 30.6.1 says most E/M visit levels are chosen by medical decision making or by time since January 1, 2023, and history and exam no longer set the level. Emergency department visits and critical care use only one of the two, as their CPT codes direct.

05Which remark codes tell me the note failed?

X12 pairs none with 150, but M25 and M26 say the information furnished does not substantiate the need for this level of service, N163 says the medical record does not support the code per its definition, and N661 says documentation does not support medical necessity.

06Do I have to refund the patient after a CO-150?

For Medicare, M26 says that if you collected an amount from the patient for this level of service, you must refund it within 30 days of the notice, citing section 1824(I) of the Social Security Act and 42 CFR 411.408. Other payers set their own refund rules.