Antibiotic susceptibility testing by the disk diffusion method, reported per plate, showing which antibiotics stop a cultured organism from growing.
- Medicare
- $0.00
- Work RVU
- 0
- Global, days
- Region
- Multi-region
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 3 cited references ↓
- Primary culture and organism identified
- Number of plates used on the lab report
- Infection diagnosis being treated
- Antibiotic plan informed by the results
- Specimen source
Applicable modifiers
Modifiers commonly billed with this code.
Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual
What this code covers
Source · Editorial summary grounded in 3 cited references ↓
87184 reports antibiotic susceptibility testing by disk diffusion. Paper disks soaked in different antibiotics are placed on a plate seeded with the organism, and the lab measures the zone where nothing grows. It is billed per plate, and a plate holds a limited number of disks.
For orthopedics, susceptibility results drive the antibiotic choice in septic arthritis, osteomyelitis, and periprosthetic infection. A six-week IV course and a PICC line depend on this report. The surgeon does not bill it, but the infection team reads it and the note should show how it changed treatment.
The lab chooses disk diffusion (87184) or a dilution method (87186). Both are not usually billed for the same organism and the same drug panel. Units should match the plates used as stated on the report. Susceptibility is billed in addition to the culture and identification codes. When a payer denies it, the cause is usually a units mismatch or a duplicate with 87186.
RVU & reimbursement
Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.
Source · CMS Physician Fee Schedule, RVU26A · January 2026
| Work RVU | 0 |
| Practice expense RVU | 0 |
| Malpractice RVU | 0 |
| Total RVU | 0 |
| Medicare national rate | $0.00 |
| Global period | days |
Payment by site of service
Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.
Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026
| Setting | Medicare rate (national) |
|---|---|
Office (PFS non-facility) Procedure performed in physician's office | $0.00 |
Common denial reasons
The recurring reasons claims for CPT 87184 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Billed with 87186 for the same organism and drugs
- Units do not match plates on the report
- No culture code on the same claim or date
- Billed by the ordering practice instead of the lab
- Missing modifier for a second organism where the payer requires it
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 3 cited references ↓
01What is the difference between 87184 and 87186?
02Is susceptibility testing included in the culture code?
03Why does susceptibility testing matter in orthopedic infections?
Sources & references
Editorial content was developed using the following public sources.
- 01CMS Physician Fee Schedule 2026
- 02CMS Clinical Laboratory Fee Schedule 2026
- 03cms.govhttps://www.cms.gov/medicare/coding-billing/national-correct-coding-initiative-ncci-edits
Mira Scribe
Mira Scribe records the antibiotic decision the provider makes from the culture results, which ties the susceptibility test to a real treatment change.
See how Mira captures CPT 87184 documentation