Modifier CQ
A complete practical guide to Modifier CQ for medical billers, coders, AR callers, physical therapy practices and Revenue Cycle Management teams.
Learn what CQ means, when it is required, why it is paired with GP, how the 10% de minimis standard works, the important 8-minute rule exceptions, payment reduction rules and how to investigate CQ-related denials.
Modifier CQ at a Glance
The essential Medicare facts every billing professional should know.
PTA Modifier
CQ identifies applicable outpatient physical therapy services furnished in whole or in part by a physical therapist assistant.
Pair With GP
When CQ applies, CMS requires CQ to be reported with the GP therapy modifier.
De Minimis Standard
The CQ modifier generally applies when the PTA’s independent portion exceeds 10% of the applicable service or unit.
Reduced Payment
Applicable services reported with CQ are paid at 85% of the otherwise applicable Part B payment amount.
What Is Modifier CQ?
Start with the Medicare definition before applying the modifier to real claims.
Official Medicare Meaning
Outpatient physical therapy services furnished in whole or in part by a physical therapist assistant.
Plain-English Explanation
Modifier CQ tells Medicare that an applicable outpatient physical therapy service was furnished in whole or in part by a PTA under a physical therapy plan of care.
CQ is not a generic “assistant” modifier. It is specifically associated with outpatient physical therapy services furnished by a physical therapist assistant.
Easy memory: CQ = PTA + outpatient PT.
CQ Must Be Paired With GP
This is one of the most important claim-edit rules to remember.
Therapy Discipline
GP identifies the service as being furnished under a physical therapy plan of care.
PTA Involvement
CQ identifies applicable service involvement by a physical therapist assistant.
Correct Combination
When CQ applies, the claim line should report CQ together with the GP therapy modifier.
Important Claim Edit
CMS states that CQ must be paired with GP. Claims with therapy-assistant modifiers that are not properly paired can be rejected or returned as unprocessable.
CQ vs CO
Do not confuse the PTA modifier with the occupational therapy assistant modifier.
CQ — PTA
Outpatient physical therapy services furnished in whole or in part by a physical therapist assistant.
CO — OTA
Outpatient occupational therapy services furnished in whole or in part by an occupational therapy assistant.
When Does Modifier CQ Apply?
CMS uses specific rules to determine when PTA involvement requires the modifier.
PTA Furnishes the Entire Service
CQ applies when the PTA furnishes all of the minutes of the service independently of the PT.
PTA Furnishes More Than 10%
CQ generally applies when the PTA’s independent portion exceeds 10% of the total minutes for the applicable service or unit.
PTA Works Independently
The calculation focuses on minutes furnished by the PTA independently of the PT for the same service.
Applicable PT Service
The service must be an applicable outpatient physical therapy service subject to the CQ rules.
Key Rule
The CQ modifier is not based simply on the fact that a PTA entered the treatment room. The actual service minutes and whether the PTA worked independently are important.
The 10% De Minimis Standard
Understand the calculation before deciding whether CQ applies.
Basic Formula
÷
Total Minutes for Service
× 100
If the applicable percentage is greater than 10% — that is, 11% or more after CMS’s rounding method — CQ generally applies.
Example
PTA provides 10 minutes of 97110 independently.
PT provides 5 minutes of the same service.
Because the PTA’s independent portion exceeds 10%, CQ applies to the applicable unit under the CMS example.
Do Not Stop at the Percentage
CMS’s rules include specific exceptions, including situations involving the final 15-minute unit and the Medicare 8-minute rule. Always apply the CMS decision sequence rather than using a simple percentage calculation for every claim.
CQ and the 8-Minute Rule
One of the most important exceptions for timed therapy services.
PT Provides 8+ Minutes
For the final 15-minute unit, if the PT independently furnishes 8 or more minutes, that final unit is billed without CQ.
PTA Minutes Still Matter
Even if the PTA also furnished minutes, the CMS exception can mean the final unit does not receive CQ when the PT independently provides at least 8 minutes.
Apply the Sequence
Determine complete 15-minute units first and then apply the applicable CMS rules to the remaining minutes.
Practical Reminder
Do not automatically place CQ on every unit simply because the PTA participated during the treatment session. CMS provides specific unit-by-unit rules.
Modifier CQ Decision Path
Use this sequence when reviewing a Medicare PT claim.
PT Service?
Confirm applicable outpatient PT service.
PTA?
Determine who furnished the service.
Independent?
Separate PTA minutes from PT minutes.
CQ Applies?
Apply CMS de minimis rules and exceptions.
Pair GP
Report CQ with the GP therapy modifier.
Complete CQ Billing Workflow
A practical front-end process for Medicare PT billing.
Modifier CQ Practical Examples
Simplified examples based on CMS billing concepts.
PTA: 10 minutes of 97110.
PT: 5 minutes of 97110.
One unit qualifies. CQ applies because the PTA furnished more than 10% of the service and the applicable de minimis rule is satisfied.
PTA: 5 minutes of 97110.
PT: 6 minutes of 97110.
One unit qualifies and CQ applies because the PTA’s independent portion exceeds 10% of the total service time.
PTA: 5 minutes of 97110.
PT: 30 minutes of 97110.
The PT furnished two complete 15-minute units. Those two units are billed without CQ. The PTA’s additional 5 minutes are recorded as part of the treatment documentation but do not create an additional billable unit.
The PT independently furnishes at least 8 minutes of the final 15-minute unit while the PTA also participates.
The final unit is billed without CQ because the PT independently furnished the required 8 or more minutes for that final unit.
The physical therapist independently provides the entire service.
CQ is not reported because the PTA did not furnish the service.
The PTA independently furnishes all minutes of an applicable outpatient PT service.
The service is furnished in whole by the PTA, so CQ applies when the service is subject to the CQ rules. The corresponding GP modifier should also be reported.
How to Calculate CQ
Understand the percentage method used after the applicable CMS steps.
| Step | What to Determine | Example | Result |
|---|---|---|---|
| 1 | Identify total minutes for the same service. | PTA 10 + PT 5 | 15 minutes |
| 2 | Identify PTA minutes furnished independently. | PTA = 10 | 10 minutes |
| 3 | Divide PTA independent minutes by total minutes. | 10 ÷ 15 | 66.7% |
| 4 | Compare with 10% de minimis standard. | 66.7% > 10% | CQ applies |
| 5 | Apply corresponding therapy modifier. | CQ + GP | Correct modifier pairing |
Important
CMS’s complete calculation methodology should be followed for each billing situation. The percentage method is not a substitute for the required unit-counting and 8-minute-rule steps.
Common Modifier CQ Mistakes
These errors can cause rejected, returned or incorrectly paid Medicare therapy claims.
CQ Without GP
Reporting CQ without the corresponding GP therapy modifier can cause the claim to be rejected or returned.
CQ on Every Unit
PTA participation does not automatically mean every unit receives CQ. Apply the CMS unit-specific rules.
Ignoring 8-Minute Rule
The final unit can be subject to an exception when the PT independently provides 8 or more minutes.
Counting Shared Minutes Incorrectly
Minutes furnished together by the PT and PTA are treated differently from PTA minutes furnished independently.
Confusing CQ With CO
CQ is for PT/PTA services. CO is for OT/OTA services.
Ignoring Documentation
The medical record must support the services, minutes, units and practitioner involvement reported on the claim.
Using CQ for SLP
CQ is a PT assistant modifier. It is not used to identify speech-language pathology services.
Using CQ for OT
Occupational therapy assistant services use CO when the applicable requirements are met.
Ignoring Provider Type
Verify that the claim is being submitted under a payment methodology to which the CQ rules apply.
When Should CQ Not Be Reported?
Important situations where the modifier should not simply be added because a PTA was present.
PT Furnishes the Service Alone
When the PT wholly provides the applicable service, CQ is not reported.
PT and PTA Provide Care Together
When the PT and PTA provide care to the patient together at the same time, CMS provides an exception to the CQ requirement.
PTA Portion Does Not Exceed the Standard
When the applicable independent PTA portion does not exceed the 10% de minimis standard, CQ generally does not apply, subject to CMS’s specific rules and exceptions.
Non-Applicable Service
The CQ rules apply to applicable outpatient PT services, not every service performed by a PTA.
Important Exception
CMS specifically identifies the situation in which the PT and PTA provide care together at the same time as an exception to the CQ requirement. Always review the exact circumstances and current CMS guidance.
CQ and the 85% Payment Rule
Why the CQ modifier matters financially for Medicare claims.
Reduced Payment
For applicable outpatient PT services furnished in whole or in part by a PTA, Medicare payment is made at 85% of the otherwise applicable Part B payment amount for dates of service on or after January 1, 2022.
Why Billing Teams Need to Know
CQ is not merely a descriptive modifier. It can directly affect Medicare reimbursement.
- Correct CQ identification prevents incorrect billing.
- Proper GP pairing helps prevent claim edits.
- Correct unit-level application supports accurate payment.
- Accurate documentation supports the reported minutes.
AR Caller Workflow for a CQ Denial
A practical root-cause process instead of simply rebilling.
Review ERA/EOB
Identify the exact denied claim line and Medicare adjustment reason.
Capture CARC/RARC
Record all adjustment and remark codes before selecting the next action.
Check CQ + GP
Verify whether CQ was reported with the required GP therapy modifier.
Review Minutes
Compare PT and PTA minutes for the affected service.
Apply CMS Rule
Determine whether the 10% standard, 8-minute rule or another CMS exception applies.
Review Documentation
Confirm that the medical record supports practitioner involvement and total treatment minutes.
Check Payment Method
Confirm whether the claim is paid under a methodology to which CQ applies.
Contact MAC
If the CMS rule is satisfied but adjudication remains unclear, contact the appropriate Medicare contractor.
Correct or Appeal
Submit the appropriate corrected claim or appeal based on the documented root cause.
Medicare AR Call Script — Modifier CQ
Questions to ask when a PT/PTA claim is denied.
CQ Documentation Checklist
Documentation should support the services and minutes reported on the claim.
Before Submission
- Medicare coverage verified.
- PT plan of care verified.
- CPT/HCPCS code verified.
- PT and PTA involvement identified.
- Total treatment minutes documented.
- PTA independent minutes documented.
- Applicable units calculated.
- CQ and GP pairing checked.
After Denial
- ERA/EOB reviewed.
- CARC/RARC captured.
- Modifier sequence reviewed.
- PTA and PT minutes rechecked.
- 10% de minimis standard reviewed.
- 8-minute rule reviewed.
- CMS billing example compared.
- MAC guidance checked.
Therapy Assistant Modifier Comparison
Quick reference for Medicare outpatient therapy billing.
| Modifier | Practitioner | Therapy Discipline | Pair With | Payment Impact |
|---|---|---|---|---|
| CQ | Physical Therapist Assistant | Physical Therapy | GP | 85% of otherwise applicable Part B amount |
| CO | Occupational Therapy Assistant | Occupational Therapy | GO | 85% of otherwise applicable Part B amount |
| GP | Physical Therapy | Physical Therapy | May pair with CQ when PTA rules apply | Discipline modifier |
| GO | Occupational Therapy | Occupational Therapy | May pair with CO when OTA rules apply | Discipline modifier |
| GN | Speech-Language Pathology | Speech-Language Pathology | Not a PTA/OTA modifier | Discipline modifier |
CQ vs GN, GO and GP
Understand the difference between discipline modifiers and therapy-assistant modifiers.
Physical Therapy
Identifies the physical therapy plan of care.
PTA
Identifies applicable PT services furnished in whole or in part by a PTA.
Occupational Therapy
Identifies the occupational therapy plan of care.
Speech Therapy
Identifies applicable speech-language pathology services under an SLP plan of care.
GP = PT discipline | CQ = PTA involvement | GO = OT discipline | GN = SLP discipline
2026 Medicare Therapy Points
Current information relevant to PT billing teams.
KX Threshold
For CY 2026, the KX threshold is $2,480 for PT and SLP services combined.
PTA Payment Reduction
Applicable PTA services are paid at 85% of the otherwise applicable Part B payment amount.
Annual Therapy Code List
CMS maintains the current therapy code list and dispositions for determining codes that sometimes or always describe therapy services.
Do Not Confuse KX With CQ
KX addresses applicable therapy-threshold and medical-necessity requirements. CQ identifies applicable PTA involvement. They serve different purposes and should not be treated as interchangeable modifiers.
Common Root Causes of CQ Denials
Identify the process failure before submitting a corrected claim.
CQ Missing
Applicable PTA service was billed without the required CQ modifier.
GP Missing
CQ was submitted without the corresponding GP therapy modifier.
CQ Overreported
CQ was added to units that did not meet the applicable CMS requirements.
Incorrect Minutes
PT and PTA minutes were incorrectly recorded or calculated.
8-Minute Rule Missed
The billing team did not apply the final-unit exception correctly.
Shared Care Misclassified
PT and PTA minutes furnished together were incorrectly treated as independent PTA minutes.
Wrong Provider Setting
CQ was applied without verifying whether the provider is paid under a methodology to which the CQ rules apply.
Documentation Gap
Medical records do not adequately support the reported treatment minutes and practitioner involvement.
Manual Billing Error
The modifier was selected manually without applying the CMS unit-level methodology.
Modifier CQ Quick Cheat Sheet
Save this section as your fast-reference guide.
- CQ = outpatient physical therapy services furnished in whole or in part by a PTA.
- CQ is a PTA modifier, not a general assistant modifier.
- CQ must be paired with GP when applicable.
- The 10% de minimis standard is important for determining when CQ applies.
- PTA independent minutes are compared with total minutes for the applicable service.
- CMS requires the specific unit-counting methodology to be applied before the percentage calculation.
- The 8-minute rule creates an important final-unit exception.
- PT-only services do not receive CQ.
- CQ is different from CO, which applies to OTA services.
- Applicable CQ services are paid at 85% of the otherwise applicable Part B payment amount.
- For CY 2026, the PT/SLP combined KX threshold is $2,480.
- Always verify the current CMS Therapy Code List and applicable MAC guidance.
Official Medicare References
Primary CMS resources used for this Modifier CQ guide.
Educational Disclaimer
This page is intended for US medical billing, coding and Revenue Cycle Management education. Medicare requirements can depend on the exact CPT/HCPCS code, claim type, provider setting, date of service and applicable MAC guidance. Always verify the current CMS and Medicare contractor requirements before billing, correcting or appealing a claim.
Modifier CQ FAQs
Common questions from medical billers, coders and AR callers.
What does Modifier CQ mean?
Modifier CQ identifies outpatient physical therapy services furnished in whole or in part by a physical therapist assistant.
What does CQ stand for?
CQ is the Medicare modifier used to identify applicable outpatient physical therapy services furnished in whole or in part by a PTA.
Does CQ need to be paired with GP?
Yes. When CQ applies, CMS requires it to be reported with the GP therapy modifier for physical therapy.
What is the difference between CQ and CO?
CQ identifies applicable physical therapy services furnished by a PTA. CO identifies applicable occupational therapy services furnished by an OTA.
Does CQ apply to every service performed by a PTA?
No. The service must be an applicable outpatient physical therapy service, and CMS’s specific rules determine whether CQ is required.
What is the 10% de minimis standard?
Generally, CQ applies when the PTA’s independently furnished portion exceeds 10% of the total minutes for the applicable service or unit, subject to CMS’s detailed methodology and exceptions.
What happens if the PT provides 8 minutes of the final unit?
For the final 15-minute unit, when the PT independently provides 8 or more minutes, CMS provides an exception under the 8-minute rule and that final unit is billed without CQ.
Is CQ required when the PT provides the service alone?
No. CQ identifies applicable PTA involvement. A service wholly provided by the PT does not receive CQ.
Is CQ required when the PT and PTA provide care together?
CMS provides an exception when the PT and PTA provide care to the patient together at the same time. The specific circumstances should be reviewed against the current CMS rule.
Does CQ reduce Medicare payment?
Yes. For applicable services, Medicare pays 85% of the otherwise applicable Part B payment amount for services furnished in whole or in part by a PTA, effective for dates of service on or after January 1, 2022.
Can CQ be used without GP?
No, when CQ applies to an outpatient PT service, CMS requires CQ to be paired with the GP therapy modifier.
What should an AR caller check for a CQ denial?
Review the ERA/EOB, CARC/RARC, CQ/GP pairing, CPT/HCPCS code, PT and PTA minutes, applicable units, 10% de minimis standard, 8-minute rule, documentation and provider payment methodology.
What is the 2026 Medicare PT KX threshold?
For CY 2026, CMS lists $2,480 for physical therapy and speech-language pathology services combined. KX is separate from CQ and should only be reported when its applicable requirements are met.
Does CQ apply to SLP services?
No. CQ is specifically associated with outpatient physical therapy services furnished in whole or in part by PTAs. Speech-language pathology has its own therapy discipline modifier, GN.
Where can I verify current CQ rules?
Use the current CMS Therapy Services page, CMS billing examples for CQ/CO, the Medicare Claims Processing Manual, the annual Therapy Code List and applicable Medicare Administrative Contractor guidance.
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