CPT code 87187: MLC susceptibility, microdilution or agar dilution2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Reports a plate-based antimicrobial lethal-concentration susceptibility result when a cultured organism requires assessment beyond growth inhibition.
Medicare pays $40.17 for 87187 under the 2026 Clinical Laboratory Fee Schedule: one national amount, the same in every state and setting.
Medicare lab fee · CLFS 2026 Q4
National CLFS amount
$40.17
In effect since Jan 1, 2026. The same amount in every state, payment locality and setting.
- Geographic adjustment
- None
- Office vs facility
- Same
- Since 2020
- Unchanged
- CMS updates
- Quarterly
Medicare pays the lesser of the lab’s charge and this amount. Patients usually owe no Part B deductible or coinsurance for covered clinical lab tests.
On this page 8 sections
What 87187 covers
This test evaluates the antimicrobial concentration needed to kill a cultured organism, rather than only inhibit its growth. A clinical microbiology laboratory performs microdilution or agar-dilution testing on a plate as part of susceptibility work after an organism has been recovered from a patient specimen. Clinicians may use the result when a lethal-concentration endpoint is requested to help guide antimicrobial selection.
Report 87187 for each plate as an add-on to the primary susceptibility procedure, commonly 87186 for the related microdilution or agar-dilution workflow. Medicare pays this laboratory test only under the CLFS. The 2026 national CLFS amount is $40.17, unchanged since 2020; one amount applies nationwide, without locality, geographic, office, or facility adjustments. The code is excluded from the physician fee schedule by statute.
This summary was written with AI assistance from CMS Clinical Laboratory Fee Schedule data. Amounts on this page come directly from CMS files.
How Medicare pays 87187
Clinical lab tests aren’t priced like physician services. They’re paid from their own fee schedule, with its own rules. See the whole lab fee schedule.
One national amount
CMS sets a single Clinical Laboratory Fee Schedule amount for 87187. There’s no geographic (GPCI) adjustment, so it pays the same in every state and payment locality.
No office or facility rate
Lab tests aren’t built from relative value units, so there’s no office and facility split: the place of service doesn’t change the CLFS amount.
Updated every quarter
CMS republishes the CLFS each quarter. New tests, often proprietary laboratory analyses (PLA codes), join during the year; existing amounts are updated each January.
Excluded from the physician fee schedule
The physician fee schedule lists 87187 with status X (excluded by statute), so the test itself is paid only from the CLFS.
87187 on the lab fee schedule since 2020
87187 · CLFS 2026 Q4 (current)
$40.17
Unchanged since Jan 1, 2020
27 quarterly CLFS releases on file, first CLFS 2020 Q1. A code missing from a quarter wasn’t on that release.
87187 compared with similar tests
- 87186Susceptibility testMicrodilution or agar dilution$8.65
- Use 87186 for the related microdilution or agar-dilution susceptibility procedure. Add 87187 when the plate is also evaluated for the lethal-concentration endpoint.
- 87181Agar susceptibilityPer antimicrobial agent$4.75
- 87181 describes agar-dilution susceptibility testing counted per agent; 87187 reports the MLC assessment by plate.
- 87188Susceptibility testMacrobroth dilution method$6.64
- 87188 identifies macrobroth dilution testing. Code 87187 concerns an MLC endpoint using microdilution or agar dilution.
87187 billing questions
What does the MLC result measure?
It assesses the antimicrobial concentration needed to kill the cultured organism, rather than merely inhibit its growth.
Is 87187 reported as a stand-alone susceptibility test?
No. It is an add-on for the lethal-concentration assessment, reported with the applicable primary susceptibility procedure, commonly 87186.
What is the billing unit?
Report one unit for each plate tested.
How does 87187 differ from 87186?
Code 87186 represents the related microdilution or agar-dilution susceptibility procedure; 87187 adds the plate-based lethal-concentration endpoint.
How does Medicare pay 87187?
Medicare pays it only through the CLFS at one nationally applicable amount, with no locality or office-versus-facility adjustment.
Where this amount comes from
FeeBase reads lab amounts directly from the CMS Clinical Laboratory Fee Schedule file for the quarter: one row per code, with its payment indicator and national amount. Contractor-priced tests are labeled, never given a made-up amount. Amounts are Medicare payment limits, not a patient’s bill or a commercial rate.
CMS CLFS 2026 Q4 · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file line behind this amount
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