Physical Therapy Denial Codes: What Each One Means and How to Fix It

By ePT Billing · Updated 1 October 2026

Quick answer: Physical therapy remittances use claim adjustment reason codes (CARCs) to explain financial adjustments and remittance advice remark codes (RARCs) to add detail or convey processing information. Not every adjustment is a denial, and not every RARC explains a reduction. The PT-specific ones trace back to a few therapy rules: the GP modifier (CO-4), the 2026 KX threshold of $2,480 (CO-119), the 8-minute rule (CO-151), NCCI pairs (CO-236), prior authorization (CO-197) and medical necessity (CO-50).

ePT Billing only works with physical therapy professionals and has over 200 clients. We examine every claim denial and appeal it the same day it is processed. Here is what each code means and how to fix it.

Physical therapy denial codes at a glance

Find a specific message: “97-pmt incl in pmt for othr svc/px” (CO-97) | N900 vs N901: missing or incomplete therapy notes | CO-45: what the adjustment means | Denial code 24 | Denial code 167 | PR-177: eligibility requirements | Denial code 243 | Corrected claim, reopening or appeal? | ePT Billing’s denial-handling process

Each row links to its section, which quotes the official wording from the X12 reason code list and X12 remark code list.

On a narrow screen, swipe the table sideways to read every column. With a keyboard, focus the table area and use the left and right arrow keys.

How do you read a denial code on a PT remittance?

Read the adjustment group code, CARC and any accompanying RARCs together. The group code assigns financial responsibility for the adjustment; the CARC explains the financial adjustment, and supplemental RARCs add detail. Informational RARCs begin with “Alert:” and convey processing information rather than explaining a specific adjustment or CARC. See the X12 RARC definitions. For Medicare, CO assigns responsibility to the provider and PR identifies patient responsibility; CMS says beneficiaries may be billed only when PR is used. Do not treat CO-119 and PR-119 as automatic instructions to send a bill: check the full remittance and applicable patient protections before billing. See CMS remittance guidance.

That combination is one Noridian, a Medicare contractor, lists for medical necessity. Medicare's manual says that, generally, CO adjustments "are considered a write off for the provider and are not billed to the patient." PR is an amount "that may be billed to the patient" (Claims Processing Manual, chapter 22, section 60.1). X12 adds, changes and retires codes over time. Each code on the X12 reason code list shows the date it started, plus a last-modified or stop date if it was changed or retired, so an unfamiliar code may simply be new.

CO-4: why does a missing GP modifier deny a PT claim?

CO-4 means the payer thinks the modifier does not fit the code. On PT claims it usually means a therapy code went out without the GP modifier, or a CQ modifier went out without GP beside it. Medicare returns these claims instead of paying them, so the fix is a corrected claim, not an appeal.

Official wording, CARC 4: "The procedure code is inconsistent with the modifier used."

Medicare rule Every "always therapy" code needs GN, GO or GP. Contractors return claims without one, using CO and CARC 4 (Claims Processing Manual, chapter 5, section 10.4). CQ, for physical therapist assistant services, must sit beside GP: "Claims not so paired will be rejected/returned as unprocessable" (section 20.1).

Fix: For Original Medicare outpatient physical therapy, check the affected line for the appropriate GP modifier; CQ must be paired with GP when the assistant-modifier rules apply. Do not apply the 10% test to the whole visit indiscriminately. Determine CQ for the applicable service or unit using the PTA's independently furnished minutes and the CMS billing examples. For 15-minute timed codes, assign full 15-minute units first. If one final unit remains and the PT independently furnished at least 8 minutes of that service, bill that final unit without CQ. CMS also provides a two-unit exception when the PT and PTA each furnish 9–14 minutes of the same service and their combined time is 23–28 minutes: one unit with CQ and one without. For untimed services, apply the service-level de minimis test where applicable. Correct the affected line and resubmit an unprocessable claim; check the payer's rules for other coverage. Remark N822 means "Missing procedure modifier(s)"; N519 means "Invalid combination of HCPCS modifiers."

CO-16: what is missing from the PT claim?

CO-16 means the claim is missing information or has a billing error, and the remark code names the gap. On Medicare PT claims, check the certifying physician first: their NPI must appear on the claim as the referring provider. When the remit says the claim is unprocessable, fix the field and send a new claim.

Official wording, CARC 16: "Claim/service lacks information or has submission/billing error(s)." X12 requires at least one remark code with it.

Medicare rule "The National Provider Identifier (NPI) of the certifying physician/NPP identified for a therapy plan of care must be included on the therapy claim" as the referring provider (chapter 5, section 10.3.5). Noridian lists the usual misses: item 17 blank, the wrong qualifier (DN is referring), a name not matching Medicare's file, or a physician not enrolled to refer.

Fix: N286 is "Missing/incomplete/invalid referring provider primary identifier." Noridian's guidance on these misses pairs CO-16 with N264 and N265, the ordering provider name and identifier remarks. MA130 means the claim is unprocessable and "no appeal rights are afforded." Correct it and resubmit.

What does denial code 24 mean?

X12 defines CARC 24 as “Charges are covered under a capitation agreement/managed care plan.” See the official X12 definition. On an Original Medicare remittance it usually means the patient was enrolled in a Medicare Advantage plan on the date of service, so the plan is the payer for that visit, not Original Medicare. Noridian, a Medicare contractor, lists that as the first common reason for CO-24. It also lists a Medicare record that has not been updated to show the patient left the plan.

Fix: Noridian’s next steps are to verify the patient’s eligibility, then bill the plan if the Medicare Advantage enrollment was valid for that date. If the enrollment has since been updated and no longer covers the date of service, submit a new claim to Medicare (Noridian JE Part B guidance on CO-24, last updated April 30, 2025; checked November 10, 2026). The group code in front of the 24 shows who the payer holds responsible, so read it first: see how to read the remittance. When coverage ended instead of moving to a managed care plan, the code is usually 27.

CO-27: why was a PT visit denied after coverage ended?

CO-27 means the patient's coverage ended before the date of service. In PT it shows up mid plan of care, when a patient switches plans or moves into Medicare Advantage between visits. Read the group code together with the reason code and any remark codes: PR identifies patient responsibility and CO identifies a contractual obligation. For Medicare, CMS says beneficiaries may be billed only when the adjustment uses PR; the Medicare Summary Notice also identifies the beneficiary’s responsibility. Before sending a patient bill, verify coverage for the date of service and whether another payer should receive the claim. See CMS remittance-advice guidance.

Official wording, CARC 27: "Expenses incurred after coverage terminated."

What does PR-27 mean on a workers’ compensation bill? PR identifies patient responsibility in the adjustment, while CARC 27 means “Expenses incurred after coverage terminated.” That code combination alone does not establish that an injured worker may be billed. Check the claim administrator’s explanation and the applicable workers’ compensation rules before transferring a balance to the patient. For example, California Labor Code section 3751(b) restricts direct collection from an employee when a provider knows a filed injury claim is pending, and specifies an exception involving written rejection notice and a copy provided to the employee. That California provision is not an all-state rule.

Fix: verify eligibility and bill the new plan. If Original Medicare denies because the patient is in a Medicare Advantage plan, the code is CO-24, "Charges are covered under a capitation agreement/managed care plan." Bill the plan (Noridian on CO-24). Billing practice, not a written rule Re-check eligibility monthly during a plan of care, and at the next visit for anyone who mentions a job or plan change.

CO-29: can you fix a timely filing denial?

CO-29 means the filing deadline passed. For Medicare, a claim must be filed within 1 calendar year after the date of service. A Medicare timely filing denial carries no appeal rights, so unless an exception applies, the money is gone. Commercial deadlines come from your payer contract.

Official wording, CARC 29: "The time limit for filing has expired." Noridian pairs it with N211: "Alert: You may not appeal this decision."

Medicare rule The deadline is 42 CFR 424.44. Exceptions are narrow: an error by Medicare or its contractor, retroactive Medicare entitlement, or a retroactive Medicare Advantage disenrollment where the plan took its payment back.

Fix: check the date of service. If it was keyed wrong, a new claim with the right date can still go through. This is the one denial no amount of charm fixes, so prevention is the whole game.

CO-50: how do you beat a medical necessity denial in PT?

CO-50 means the payer decided the service was not medically necessary. In PT that usually means the notes did not show a need for a therapist's skill, or the diagnosis did not meet a coverage policy. You fix it with records, not a new claim: appeal with the evaluation, plan of care and progress notes.

Official wording, CARC 50: "These are non-covered services because this is not deemed a 'medical necessity' by the payer."

Medicare rule Skill is the test, not improvement. The manual says: "Medicare coverage does not turn on the presence or absence of a beneficiary's potential for improvement from the therapy, but rather on the beneficiary's need for skilled care" (Benefit Policy Manual, chapter 15, section 220.2). Some denials are fixed rules: Medicare denies 97026 infrared therapy for peripheral neuropathy and wound or ulcer diagnoses with CO-50 (chapter 5, section 20.4).

Fix: with N115, check the diagnosis against your contractor's policy in the Medicare Coverage Database. If the coding was right, request a redetermination with the records. For Original Medicare outpatient therapy that you expect to be denied as not medically reasonable and necessary, issue a valid Advance Beneficiary Notice of Non-coverage (ABN) before providing the service when required to transfer financial liability. CMS says you may be held financially liable if you do not issue the required notice; an ABN is not a universal remedy for every reason Medicare might refuse payment. Do not use the CMS-R-131 ABN for Medicare Advantage services. Follow the CMS ABN requirements.

CO-97: which PT services are bundled?

CO-97 means the payer counted the service as already paid inside another one. The classic PT case is 97010, hot or cold packs: Medicare's 2026 fee schedule file lists it as a bundled code, so it never pays separately. Do not treat every CO-97 adjustment as an automatic write-off: first verify which related service was paid and whether the bundling or duplicate-service decision is correct.

Official wording, CARC 97: "The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated."

Medicare rule In the 2026 relative value file (RVU26D), 97010 has status B: "Payment for covered services are always bundled into payment for other services not specified." Remark M15 may ride along: "Separately billed services/tests have been bundled as they are considered components of the same procedure."

Fix: compare the adjusted line with the prior claim, payment and remark codes. If the service is correctly bundled, do not seek separate payment or transfer a CO adjustment to the patient. If the payer treated a distinct service as a duplicate, check the documentation and applicable modifier requirements before disputing it. Noridian's CO-97 duplicate-service guidance allows an appeal with documentation showing that the services were not duplicates; this does not make every bundled service separately payable. For NCCI code-pair edits, see CO-236 and modifier limits. Follow the payer's correction or appeal instructions rather than automatically adding a modifier.

What does “97-pmt incl in pmt for othr svc/px” mean?

In plain language, “pmt incl in pmt for othr svc/px” means payment is included in payment for another service or procedure. With reason code 97, this is an abbreviated description of the adjustment—not a separate denial code. X12 defines CARC 97 as: “The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.”

Match the message to the adjusted claim line and review the full remittance, related service, group code and any remark codes before deciding what to do next. The abbreviation alone does not identify which other service includes the payment. For the group-code distinction, see how to read a remittance; for next steps, see corrected claims, reopenings and appeals.

CO-119: is it a visit limit or a missing KX modifier?

CO-119 means a benefit maximum was reached. On commercial plans that is often a yearly visit limit. On Medicare it is how claims over the KX threshold are denied when the KX modifier is missing. For 2026 the threshold is $2,480 for physical therapy and speech-language pathology combined.

Official wording, CARC 119: "Benefit maximum for this time period or occurrence has been reached."

Medicare rule CMS: "Claims for services over the KX modifier threshold amounts without the KX modifier are denied." The 2026 amounts are $2,480 for PT and SLP combined and $2,480 for OT, with targeted medical review above $3,000 (CMS Therapy Services). For Original Medicare therapy, distinguish a missing KX modifier from services that are not medically reasonable and necessary. KX indicates that medically necessary services are justified in the medical record; GA indicates that an Advance Beneficiary Notice of Non-coverage (ABN) was issued as required for therapy that is not medically reasonable and necessary. CMS says not to use GA and KX together. Do not treat an ABN as a substitute for correcting a missing KX modifier or as automatic permission to bill a patient. The CMS-R-131 ABN is not used for Medicare Advantage services (CMS ABN tutorial: therapy modifiers and requirements).

Fix: if KX belonged on the claim, ask for a reopening: "contractors may reopen and/or adjust the claim, if it is brought to their attention." Do not add KX to everything to be safe. CMS calls KX use with "no indication that the cap is likely to be exceeded" abusive (both quotes: chapter 5, section 10.3.3).

CO-151: are your 8-minute rule units right?

CO-151 means the payer thinks the units or visits billed are more than the information supports. On Medicare claims, check whether the denial involves a Medically Unlikely Edit (MUE). An MUE tests units for a code, but its adjudication indicator determines whether it applies to a claim line or the date of service; it is not the same as the 8-minute rule. Check the unit math first: under the 8-minute rule, total timed units are limited by total timed minutes.

Official wording, CARC 151: "Payment adjusted because the payer deems the information submitted does not support this many/frequency of services." Noridian uses it when units exceed the "Medically Unlikely Edit (MUE) maximum established by CMS."

Medicare rule Units for 15-minute timed codes follow total timed minutes for the day (chapter 5, section 20.2):

The pattern continues in 15-minute steps. CMS's own example: 24 minutes of 97112 plus 23 minutes of 97110 is 47 minutes, so 3 units, billed as 2 of 97112 and 1 of 97110. Check any visit in our free 8-minute rule calculator before the claim goes out.

Fix: correct any unit-count or coding error first. For a Medicare MUE denial, check the applicable provider-type edit file and MUE adjudication indicator (MAI). MAI 1 is a claim-line edit; MAI 2 and 3 are date-of-service edits that total the same code across lines, so splitting lines or adding modifiers does not bypass those daily edits. MAI 2 is an absolute date-of-service edit based on policy, not a limit overridden merely by documenting more minutes. MAI 3 permits contractor review of units above the edit when records show the services were actually furnished, correctly coded, and medically reasonable and necessary. For an appropriate reopening or appeal, follow your Medicare contractor's instructions and provide supporting medical records, not just a minute total. CMS also allows review of qualifying MAI 1 denials. See the CMS MUE FAQs and MAI guidance. Most codes' limits are on the CMS MUE page. CMS keeps some MUE values confidential, so a missing code there does not mean it has no limit. Billing practice Some commercial payers count time differently, so check each payer's policy.

What does denial code 167 mean?

X12 defines CARC 167 as “This (these) diagnosis(es) is (are) not covered.” Its usage note says to refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present. See the official X12 definition and usage note.

The reason code describes the diagnosis-related coverage adjustment; it does not, by itself, establish that the patient can be billed. Read the accompanying group code and the payer’s coverage information before deciding the next step. See how to read the remittance and the patient-billing FAQ.

What does PR-177 mean on a physical therapy claim?

Official wording, CARC 177: “Patient has not met the required eligibility requirements.” The X12 reason code list defines PR as “Patient Responsibility”; PR is the adjustment group and 177 is the reason, not a physical-therapy-specific procedure code.

Billing follow-up checklist: read the full remittance and any remark codes, then ask the payer which eligibility requirement was not met for the date of service. Compare that explanation with the patient's plan and eligibility records before choosing a correction or dispute. Do not treat the PR prefix alone as permission to collect from the patient: check the applicable plan terms and patient protections first. Use the correction, reopening and appeal guide to distinguish the available routes; the code alone does not set the deadline.

What does denial code 243 mean?

X12 defines CARC 243 as “Services not authorized by network/primary care providers.” X12’s note says it replaced deactivated code 38. See the official X12 definition (checked November 10, 2026). Three nearby codes are easy to mix up with it:

• 242: “Services not provided by network/primary care providers.”
• 288: “Referral absent”.
• 197: “Precertification/authorization/notification/pre-treatment absent.”

The reason code names what the payer says is missing. It does not, by itself, establish that the patient can be billed, even when it arrives as PR-243. Read the group code and the plan’s referral and network rules before deciding the next step: see how to read the remittance and the patient-billing FAQ. Billing practice, not a written rule Check whether the plan required a referral or authorization from the patient’s primary care or network provider for physical therapy on that date. If one was on file, follow that payer’s correction or appeal instructions to get it matched to the claim.

CO-197: what about Medicare Advantage prior authorization?

CO-197 reports that required precertification, authorization, notification or pre-treatment is absent; CO-198 reports that it was exceeded. Before choosing a correction or appeal, check the patient’s plan requirements for the service and date, the accompanying remark codes, and any existing approval. Compare the approved services, visits or units and dates with the claim. If an approval exists, check whether the payer matched it to the claim. Follow that payer’s correction or appeal instructions rather than assuming every authorization-related denial needs the same response.

Official wording: CARC 197, "Precertification/authorization/notification/pre-treatment absent." CARC 198, "Precertification/notification/authorization/pre-treatment exceeded."

A real example from a practice we bill for: at a two-location PT practice, payers sometimes denied visits for "no authorization" when the authorization was right there in the patient's chart. Sending that back to the front desk and calling the payer again wastes days. What works: the billing manager, who has access to the chart, pulls the authorization and gets the claim corrected on the same call with the payer.

Medicare Advantage rules Federal rules give PT clinics firm ground with Medicare Advantage plans:

• An approved authorization for a course of treatment "must be valid for as long as medically necessary to avoid disruptions in care." New enrollees get at least a 90-day transition for an active course of treatment (42 CFR 422.112(b)(8)).
• Once a plan approves a service, it may not deny it later for lack of medical necessity, except for good cause or fraud (42 CFR 422.138(c)).
• Since 1 January 2026, standard decisions on services that need prior authorization are due within 7 calendar days (42 CFR 422.568). Expedited ones are due within 72 hours (42 CFR 422.572). Both can be extended in limited cases.
• Every denial notice must "state the specific reasons for the denial" (42 CFR 422.568(e)).

Fix: M62 is "Missing/incomplete/invalid treatment authorization code." N54 is "Claim information is inconsistent with pre-certified/authorized services." If the auth existed, put the number on a corrected claim. If the patient joined the plan mid-course, cite the 90-day transition rule in your appeal.

CO-236: when can you use modifier 59 or XU on PT codes?

CO-236 means two codes billed the same day hit a National Correct Coding Initiative pair edit. In PT, modifier 59 or XU can bypass some pairs, but only when the services happened in different timed intervals and your notes show it. If the services overlapped, the denial is correct.

Official wording, CARC 236: "This procedure or procedure/modifier combination is not compatible with another procedure or procedure/modifier combination provided on the same day according to the National Correct Coding Initiative or workers compensation state regulations/ fee schedule requirements."

Medicare rule From the 2026 NCCI policy manual, chapter 11, section P:

• Timed-code pairs "may be bypassed with modifier 59 or XU if the 2 procedures of a code pair edit are performed in different timed intervals even if sequential during the same patient encounter."
• Re-evaluation (97164) "shall not be routinely reported during a planned course" of therapy. If status changes, report it with 59 or XU.
• 97750 is not separately reportable on the same day as a PT evaluation or re-evaluation by the same practitioner or specialty.
• A physical therapist may report one evaluation or re-evaluation per date of service.

Use the most specific modifier: XE separate encounter, XS separate structure, XP separate practitioner, XU unusual non-overlapping service. "Different diagnoses are not adequate criteria" for 59, XE or XS (NCCI chapter 1).

Fix: look up the pair in the CMS PTP edit tables. Modifier indicator 0 means never; 1 means a modifier is allowed when it fits. If the notes support separate intervals, add XU or 59 to the column two code and ask for a reopening or appeal. If not, write it off. Providers may not bill the patient for NCCI denials or use an ABN for them (Noridian on CO-236).

CO-252: what documentation does the payer want?

CO-252 means the payer will not decide the claim until it gets documents. For PT that is usually therapy notes, the plan of care or the certification, and the remark code tells you which. Send exactly what it names, through the payer's attachment process, and reference the claim number.

Official wording, CARC 252: "An attachment/other documentation is required to adjudicate this claim/service." PT remark codes include N465 "Missing Physical Therapy Notes/Report," N900 "Missing Therapy Notes/Report," N485 "Missing Physical Therapy Certification" and M127 "Missing patient medical record for this service."

Medicare rule Clinics get 45 calendar days to answer a documentation request from a Medicare Administrative Contractor, or 30 days for a UPIC. For Original Medicare medical review, contractors may accept late documentation for good cause, such as natural disasters or interruptions in business practices. Otherwise, claims are denied when requested records are not received by the applicable deadline (Program Integrity Manual, chapter 3, section 3.2.3.2). If you then ask for a redetermination, it must be processed as a reopening (42 CFR 405.980(a)(2)).

What does the N900 remark code mean?

N900 means "Missing Therapy Notes/Report." It is a remittance advice remark code (RARC), not a claim adjustment reason code (CARC). Read it with the accompanying reason and group codes to understand the adjustment.

Do not confuse N900 with N901: X12 defines N901 as "Incomplete/Invalid Therapy Notes/Report." N900 identifies missing notes or a report; N901 identifies incomplete or invalid notes or a report. Both definitions come from the official X12 remark code list.

Next check: review the payer's request for the claim and dates of service, the requested records, the submission method and the response deadline. For N901, check which part of the submitted documentation the payer considers incomplete or invalid rather than assuming the records were never received. The remark code alone does not establish a universal deadline or guarantee payment after records are submitted.

Plan of care certification: what do M141 and N238 mean?

M141 and N238 are remark codes for a missing or invalid physician-certified plan of care. Medicare calls a missing certification a technical denial, meaning a requirement in the law was not met. It is fixable: a certification produced later, with a reason for the delay, can overturn the denial.

Official wording: M141, "Missing physician certified plan of care." N238, "Incomplete/invalid physician certified plan of care." N486, "Incomplete/invalid Physical Therapy Certification." Look for these whatever reason code they arrive with.

Medicare rule From the Benefit Policy Manual, chapter 15, section 220.1.3 and 42 CFR 424.24(c):

• Initial certification is timely when signed and dated within 30 days after the first treatment, including the evaluation. A verbal order needs a signature within 14 days.
• Recertification is required at least every 90 days.
• Exception: a written order or referral is in the record, and you can prove the plan reached the physician, NP, PA or CNS within 30 days of the initial evaluation. Then no signature is needed.
• Late is not fatal: "If an appropriate certification is later produced, the denial shall be overturned."

Fix: get the signed certification with a short reason for the delay, then ask for a reopening or appeal. For Original Medicare, distinguish the setting before assigning responsibility. The Benefit Policy Manual, chapter 15, section 220.1.3(E) says a provider furnishing services under a provider agreement described in 42 CFR 489.21 may not charge the beneficiary for a missing-certification denial. For services furnished by a supplier in a physician/NPP or therapist office, the manual says a technical denial for absent certification results in beneficiary liability and recommends explaining the certification requirement and consequences to the patient. It also allows reopening or reversal on appeal, as appropriate, when delayed certification is produced.

What does CO-45 mean on a physical therapy remittance?

CARC 45 means “Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.” It identifies an adjustment to the billed charge, not automatically a denial of the entire service. X12 specifies that this adjustment cannot equal the total service or claim charge and must not duplicate payments or contractual reductions from prior payers. Code 45 can appear with CO or PR, depending on liability. See the official X12 definition and usage notes.

Next check: compare the billed charge, applicable allowed amount, payment and other adjustments on the remittance before deciding whether the reduction is correct. Do not automatically appeal a correctly applied contractual reduction or transfer a CO amount to the patient. CMS Medicare remittance guidance assigns CO responsibility to the provider; PR identifies patient responsibility, but a PR label alone is not a blanket authorization to bill without checking applicable patient protections.

What does remark code N448 mean?

X12 defines N448 as “This drug/service/supply is not included in the fee schedule or contracted/legislated fee arrangement.” N448 is a remittance advice remark code, not a claim adjustment reason code. See the official X12 remark-code list.

Read N448 alongside the claim adjustment reason code and group code on the remittance. Compare the service with the applicable payer fee schedule or contracted/legislated fee arrangement before selecting a response. For the broader context, see how to read a PT remittance.

Why was a PT line paid less but not denied?

Two Medicare adjustments look like denials but are not. CO-59 is the multiple procedure payment reduction. Medicare pays the therapy unit with the highest practice expense in full, then 50% of the practice expense on every other therapy unit that day. Remark N851 flags the 15% cut on services billed with CQ.

Official wording: CARC 59, "Processed based on multiple or concurrent procedure rules." RARC N851, "Payment reduced because services were furnished by a therapy assistant."

Medicare rule The 50% reduction and CARC 59 are in chapter 5, section 10.7. PTA services have been paid at 85% since 1 January 2022 (CMS Therapy Services). Billed right, there is nothing to fix. CQ on visits where the PTA stayed under the 10% line is money left on the table.

Resubmit, reopen or appeal: which one fixes a PT denial?

Match the route to the problem. Unprocessable claims, like CO-16 with MA130, need a new corrected claim. Clerical slips, like a forgotten KX, go through a reopening: within 1 year for any reason, or at any time when a clerical error caused the denial. Disagreements on the merits, like CO-50, go to a Medicare redetermination within 120 days of receiving the notice.

On a narrow screen, swipe the table sideways to read every column. With a keyboard, focus the table area and use the left and right arrow keys.

How ePT Billing handles these denial codes

This is ePT Billing's published process, matched to the codes above.

• Before the claim goes out (CO-4, CO-16): every claim is audited daily before it is sent to the insurance company, to catch clerical errors. Those are the slips behind a missing GP modifier or a blank referring provider.
• Authorizations (CO-197, CO-198): on request, ePT sends pre-authorizations to the insurance company. A missing authorization is exactly what CO-197 reports.
• When a denial arrives (CO-50, CO-151, plan of care): every claim denial is examined and appealed the same day it is processed. For Medicare, a same-day appeal sits far inside the 120-day redetermination window.
• Daily reports (CO-16 and every appealed code): your daily summary lists every error found in patient files and how many overdue claims were appealed that day, plus a detailed monthly report.

Physical therapy denial codes: FAQ

What are the most common physical therapy denial codes?

The codes tied to PT-specific billing rules are CO-4 (missing GP modifier), CO-16 (missing claim information), CO-50 (medical necessity), CO-119 (no KX over the threshold), CO-151 (units), CO-197 (prior authorization), CO-236 (NCCI pairs) and CO-252 (records requested). Your own top five come from your remits: sort 12 months of denials by reason code.

What does denial code CO-97 mean in physical therapy?

CO-97 means the payer treated the service as included in another service it already paid. Medicare's 2026 fee schedule file lists 97010, hot or cold packs, as a bundled code, so it is never paid separately. A correctly applied CO adjustment is not transferred to the patient, but CO-97 alone does not establish that the payer's decision was correct. Review the related claim and documentation; an incorrect duplicate-service decision may be disputed using the payer's appeal process. Review the CO-97 investigation steps above.

What is the KX modifier threshold for 2026?

For 2026, Medicare's KX modifier threshold is $2,480 for physical therapy and speech-language pathology combined, and a separate $2,480 for occupational therapy. Claims above it without the KX modifier are denied. Targeted medical review applies above $3,000.

Can I bill the patient for a CO denial?

Do not transfer a correctly applied contractual-obligation (CO) adjustment to the patient. For Medicare, a PR adjustment is necessary before billing the beneficiary, but it does not override other billing protections: Qualified Medicare Beneficiaries cannot be billed for Part A or Part B cost sharing on covered services. For Original Medicare services that are generally covered but expected to be denied, follow the applicable Advance Beneficiary Notice (ABN) requirements before providing the service when transferring financial liability. An ABN is not a universal way to convert a denial into patient responsibility, and the CMS ABN is not used for Medicare Advantage services.

How long do I have to appeal a Medicare physical therapy denial?

A Medicare redetermination must be filed within 120 calendar days of receiving the initial determination, and receipt is presumed to be 5 days after the notice date. Clerical errors, like a missing KX modifier, go through a reopening instead. You can request one within 1 year of the initial determination for any reason, and a clerical error behind an unfavorable determination can be reopened at any time.

What is the difference between a CARC and a RARC?

A CARC, or claim adjustment reason code, says why a claim or line was paid differently than billed. A RARC, or remittance advice remark code, adds detail, such as which document is missing. X12 maintains both lists, and some reason codes, like CO-16 and CO-252, must come with at least one remark code.

What is denial management in physical therapy billing?

There is no official definition. In billing practice, denial management means working every denied or reduced claim line instead of writing it off, and fixing whatever caused it. A workable routine has four steps. First, read the group code, reason code and remark codes together. Second, sort your denials by reason code so the ones that repeat stand out. Third, send each denial down the right route, a corrected claim, a reopening or an appeal, before its deadline; a Medicare redetermination has to be filed within 120 days of receiving the notice. Fourth, fix the cause before the next claim goes out, so the same code stops coming back. How ePT Billing handles these denial codes shows the process we publish for our own clients.

Read this next: 10 reasons physical therapy insurance claims get denied, and check unit math with the 8-minute rule calculator.