CPT code 86344: Phagocytosis, white blood cell function2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Measures leukocyte phagocytosis, the particle-engulfing function of white blood cells, when a laboratory assessment of this functional endpoint is reported.
Medicare pays $10.39 for 86344 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
$10.39
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 7 sections
What 86344 covers
Code 86344 identifies laboratory measurement of leukocyte phagocytosis, a white blood cell function. The assay evaluates cells’ ability to engulf particles, rather than reporting a cell count, cell-subset count, histamine-release response, or lymphocyte transformation. It is distinct from tests that measure other immune-cell functions. The measured endpoint is phagocytic function. It characterizes white blood cell activity, not the number of leukocytes present.
Report 86344 for the leukocyte phagocytosis assay. Medicare pays 86344 through the Clinical Laboratory Fee Schedule (CLFS) at one nationally set amount that applies in every state and locality, without geographic or office/facility adjustment. The 2026 national CLFS amount is $10.39, unchanged from 2020 through 2025. The test is paid only through the CLFS and is excluded from the physician fee schedule.
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 86344
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 86344. 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 86344 with status X (excluded by statute), so the test itself is paid only from the CLFS.
86344 on the lab fee schedule since 2020
86344 · CLFS 2026 Q4 (current)
$10.39
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.
86344 compared with similar tests
- 86343Histamine releaseLeukocyte assay$12.46
- Use 86344 for leukocyte particle engulfment. Code 86343 measures leukocyte histamine release.
- 86352Cell function assayStimulated biomarker assay$135.86
- Code 86352 describes a stimulated cell function assay; 86344 specifically measures leukocyte phagocytosis.
- 86353Lymphocyte responseMitogen- or antigen-induced$49.03
- Code 86353 measures lymphocyte transformation. Use 86344 when the test measures leukocyte phagocytosis.
86344 billing questions
How does 86344 differ from 86343?
86344 measures leukocyte phagocytosis, or particle engulfment. Code 86343 measures leukocyte histamine release, a different functional response.
Should 86344 be used for a lymphocyte function test?
No. Code 86344 measures leukocyte phagocytosis; lymphocyte transformation is reported with 86353.
Does 86344 measure a leukocyte count?
No. It measures leukocyte phagocytic function rather than the number of leukocytes or a cell-subset count.
Is 86344 paid under the CLFS or physician fee schedule?
Medicare pays 86344 through the CLFS. The code is excluded from the physician fee schedule.
How does 86344 differ from the stimulated cell function assay?
Code 86344 measures leukocyte phagocytosis. Code 86352 describes a stimulated cell function assay.
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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