CPT code 86645: CMV antibody, igM antibody2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Laboratories report this serologic assay when clinicians request testing for IgM antibodies to cytomegalovirus (CMV).
Medicare pays $16.85 for 86645 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 86645 covers
This laboratory assay detects IgM antibodies directed against cytomegalovirus (CMV). It is used in serologic evaluation for suspected CMV infection; an IgM result by itself does not establish when infection occurred. Clinical laboratories perform and report the test for ordering clinicians, commonly using serum. Interpretation may consider symptoms, history, and other CMV testing.
Report 86645 for the CMV IgM antibody assay; use 86644 when the test performed is CMV antibody testing without the IgM-specific designation. CMV nucleic acid assays measure a different target. Medicare pays 86645 under the CLFS at one national amount in every state and locality, without geographic or office-versus-facility adjustment. The 2026 national amount is $16.85, unchanged since 2020. It is paid only through the CLFS.
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 86645
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 86645. 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 86645 with status X (excluded by statute), so the test itself is paid only from the CLFS.
86645 on the lab fee schedule since 2020
86645 · 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.
86645 compared with similar tests
- 86644CMV antibodyGeneral antibody assay$14.39
- Choose 86645 for the CMV IgM antibody assay. Code 86644 describes CMV antibody testing without that IgM-specific designation.
- 87496CMV testAmplified-probe detection$35.09
- Code 87496 detects CMV nucleic acid using a direct-probe method; 86645 measures CMV IgM antibodies.
- 87497CMV viral loadQuantitative nucleic acid test$42.84
- Code 87497 detects CMV nucleic acid using an amplified-probe method; 86645 measures CMV IgM antibodies.
86645 billing questions
How does 86645 differ from 86644?
86645 identifies the CMV IgM antibody assay. Code 86644 describes CMV antibody testing without the IgM-specific designation.
Is 86645 a CMV DNA test?
No. It measures CMV IgM antibodies; CMV nucleic acid tests detect the virus's genetic material.
Should the IgM result be interpreted by itself?
No. An IgM result alone does not establish when CMV infection occurred; interpretation may consider symptoms, history, and other CMV testing.
How does Medicare pay for 86645?
Medicare pays it through the CLFS at one national amount, without geographic or office-versus-facility adjustment. It is paid only through the CLFS.
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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