CPT code 86334: Immunofixation, serum specimen2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Serum immunofixation is an immunologic analysis used to evaluate serum proteins when clinicians investigate or characterize a suspected monoclonal protein.
Medicare pays $22.34 for 86334 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
$22.34
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 86334 covers
Serum immunofixation is an immunologic analysis performed on serum using an electrophoretic technique. Clinicians may order it to evaluate a suspected monoclonal protein, including during assessment of plasma cell disorders. It can be used alongside serum protein electrophoresis, which separates and measures protein fractions, to help characterize an abnormal finding. Clinical laboratories perform the analysis and report the result to the ordering clinician.
Report 86334 for serum immunofixation; immunofixation performed on urine or cerebrospinal fluid is reported with a different code. Medicare pays the laboratory test under the CLFS at one national amount across localities, without geographic or office-versus-facility adjustment. The 2026 national CLFS amount is $22.34, unchanged from 2020 through 2026. A separate physician interpretation is payable under the physician fee schedule when billed with modifier 26.
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 86334
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 86334. 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 86334 with status X (excluded by statute), so the test itself is paid only from the CLFS.
Physician interpretation (modifier 26)
A physician’s interpretation is billed separately with modifier 26 and paid under the physician fee schedule: $17.70 nationally in the office, before locality adjustment.
86334 on the lab fee schedule since 2020
86334 · CLFS 2026 Q4 (current)
$22.34
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.
86334 compared with similar tests
- 86320ImmunoelectrophoresisSerum$29.92
- Code 86320 is for serum immunoelectrophoresis, a different technique. Use 86334 when the performed serum test is immunofixation.
- 86335ImmunofixationConcentrated urine or CSF$29.35
- Both codes describe immunofixation, but 86335 is for urine or cerebrospinal fluid; 86334 is for serum.
- 84165Protein electrophoresisSerum fractionation and quantitation$10.74
- Code 84165 reports serum protein electrophoresis, which separates and measures protein fractions. Code 86334 reports serum immunofixation and may be performed alongside it.
86334 billing questions
When should 86334 be reported instead of 86335?
Report 86334 for immunofixation performed on serum. Code 86335 is for immunofixation of urine or cerebrospinal fluid.
How does 86334 differ from serum protein electrophoresis?
Serum protein electrophoresis separates and measures protein fractions, while immunofixation is an immunologic analysis used to characterize a suspected monoclonal protein. The tests may be ordered together.
Can a physician interpretation be billed separately?
Yes. A separate physician interpretation is payable under the physician fee schedule when billed with modifier 26; the laboratory test is paid under the CLFS.
How does Medicare pay for the laboratory test?
Medicare pays 86334 under the CLFS at one national amount across localities, without geographic 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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