CPT modifier
Modifier 91: Repeat clinical diagnostic lab test
Modifier 91 is a CPT modifier. In plain terms: The same lab test was run again on the same day to get later results for the patient's care.
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- Modifier
- 91
- Type
- CPT (Level I) modifier, maintained by the AMA
- Plain description
- The same lab test was run again on the same day to get later results for the patient's care.
- How it is used
- Not for repeats because of a test or equipment problem, or for confirming a result.
- Claim form
- CMS-1500 item 24D, up to four modifiers per line. 837P SV101-3 to SV101-6.
The CPT descriptor is AMA copyright and is not shown here. The description above is written by Rivvi. Read the CMS guidance linked above for Medicare's rules.
Distinct and repeat services
- 59Distinct procedural service
- XESeparate encounter, a service that is distinct because it occurred during a separate encounter
- XPSeparate practitioner, a service that is distinct because it was performed by a different practitioner
- XSSeparate structure, a service that is distinct because it was performed on a separate organ/structure
- XUUnusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
- 76Repeat procedure by the same physician
- 77Repeat procedure by another physician
Laboratory
Related modifiers
- 59Distinct procedural service
- XESeparate encounter, a service that is distinct because it occurred during a separate encounter
- XPSeparate practitioner, a service that is distinct because it was performed by a different practitioner
- XSSeparate structure, a service that is distinct because it was performed on a separate organ/structure
- XUUnusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
- 76Repeat procedure by the same physician
- 77Repeat procedure by another physician
- 90Reference (outside) laboratory
- 92Alternative laboratory platform testing
- QWCLIA waived test
Related pages
- All CPT and HCPCS modifiersA to Z list
- CMS-1500 claim formModifiers go in item 24D
- Denial code CO-4Modifier missing or does not fit the code
- Denial code CO-182Modifier invalid on the date of service
- Denial code CO-97Included in another service
- Denial code CO-236Procedure or modifier pair not compatible
- Denial code CO-B23Not allowed under the lab's CLIA certificate
- HCPCS Level II code lookup
- Denial and remark codes
Questions
What does modifier 91 mean?
Modifier 91 is a CPT modifier. In plain terms: The same lab test was run again on the same day to get later results for the patient's care.
Is modifier 91 a CPT or a HCPCS modifier?
91 is a CPT (Level I) modifier. The AMA maintains CPT modifiers. Two-character codes with a letter, such as GT or XU, are HCPCS Level II modifiers from CMS.
Where does modifier 91 go on a claim?
On the CMS-1500 it goes in item 24D next to the procedure code. Each line holds up to four modifiers. On an 837P it goes in SV101-3 to SV101-6.
When is modifier 91 used?
Not for repeats because of a test or equipment problem, or for confirming a result.
What denial comes back when a modifier is wrong?
A missing or mismatched modifier often comes back as CARC 4. A modifier that was not valid on the date of service comes back as CARC 182. A bundling edit the modifier should have bypassed comes back as CARC 97 or 236.