CPT code 86788: West Nile IgM, igM antibody2026 Medicare lab fee · Clinical Laboratory Fee Schedule
West Nile virus IgM antibody testing supports evaluation of recent infection, including suspected West Nile fever or neuroinvasive disease.
Medicare pays $16.85 for 86788 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
$16.85
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 86788 covers
Code 86788 identifies laboratory analysis for IgM antibodies to West Nile virus. Clinicians use this serologic test when evaluating a patient for possible recent West Nile virus infection, including suspected meningitis or encephalitis. The code identifies the IgM antibody target rather than an antibody test for a different virus. A clinical laboratory performs and reports the assay, and clinicians interpret the result alongside the patient's presentation and other diagnostic findings.
Report 86788 for the West Nile virus IgM assay, distinguishing it from 86789, the separate West Nile virus antibody test. Medicare pays 86788 only through the CLFS, at one national amount across localities, without an office-versus-facility adjustment. The 2026 national CLFS amount is $16.85, unchanged since 2020.
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 86788
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 86788. 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 86788 with status X (excluded by statute), so the test itself is paid only from the CLFS.
86788 on the lab fee schedule since 2020
86788 · CLFS 2026 Q4 (current)
$16.85
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.
86788 compared with similar tests
- 86789West Nile antibodyGeneral antibody assay$14.39
- 86788 is specific to West Nile virus IgM. 86789 identifies the separate West Nile virus antibody assay.
- 86790Virus antibodyVirus not otherwise specified$12.88
- Use 86788 for a West Nile virus-specific IgM assay; 86790 is for a virus antibody test not otherwise specified.
- 86794Zika antibodyIgM specific$16.85
- Both identify IgM antibody testing, but 86794 is for Zika virus and 86788 is for West Nile virus.
86788 billing questions
How does 86788 differ from 86789?
86788 identifies West Nile virus IgM antibody testing. Use 86789 for the separate West Nile virus antibody test when that is the assay performed.
When is this test typically ordered?
It is used when recent West Nile infection is suspected, including evaluation of possible meningitis or encephalitis.
Can 86788 and 86789 both be reported?
They identify distinct West Nile antibody assays. Report each only when the corresponding test was performed.
How does Medicare pay for 86788?
Medicare pays it through the CLFS at one national amount across localities, with no 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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