CPT code 82131: Amino acid test, single, quantitative2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Quantitative analysis of one amino acid per specimen is reported with 82131, distinct from qualitative testing and quantitative multi-analyte amino acid codes.
Medicare pays $22.98 for 82131 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
$22.98
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 82131 covers
This laboratory service reports quantitative analysis of a single amino acid in a specimen. Code 82131 distinguishes a one-amino-acid quantitative analysis from qualitative testing of one amino acid (82127), qualitative testing of multiple amino acids (82128), and quantitative testing of multiple amino acids. Code 82136 represents quantitative analysis of two to five amino acids, while 82139 represents six or more. The applicable code follows the test's qualitative or quantitative method and the number of amino acids analyzed in the specimen.
Medicare pays 82131 only through the Clinical Laboratory Fee Schedule (CLFS); it is excluded from the physician fee schedule. The 2026 national CLFS amount is $22.98, and the amount has been unchanged from 2020 through 2026. The CLFS amount is the same across states and localities, with no geographic or office-versus-facility adjustment. The service is reported per specimen and describes quantitation of one amino acid for each specimen.
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 82131
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 82131. 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 82131 with status X (excluded by statute), so the test itself is paid only from the CLFS.
82131 on the lab fee schedule since 2020
82131 · CLFS 2026 Q4 (current)
$22.98
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.
82131 compared with similar tests
- 82127Amino acid testQualitative, one analyte$14.18
- Choose 82131 for quantitative analysis of one amino acid; choose 82127 for qualitative testing of one amino acid.
- 82128Amino acid analysisMultiple, qualitative$13.87
- 82128 is for qualitative testing of multiple amino acids; 82131 is for quantitative analysis of one.
- 82136Amino acidsTwo to five amino acids$19.61
- 82136 is for quantitative analysis of two to five amino acids per specimen. 82131 is for one.
- 82139Amino acidsSix or more, quantitative$16.87
- 82139 is for quantitative analysis of six or more amino acids per specimen. 82131 is for one.
82131 billing questions
When should 82131 be used instead of 82136 or 82139?
Use 82131 for quantitative analysis of one amino acid per specimen. Code 82136 is for two to five amino acids, and 82139 is for six or more.
How does 82131 differ from 82127?
Both concern one amino acid, but 82131 is quantitative and 82127 is qualitative.
How many units are reported?
The service is defined per specimen and describes quantitative analysis of one amino acid in each specimen.
Does Medicare pay a separate physician interpretation for this test?
Medicare pays 82131 through the CLFS only; the code is excluded from the physician fee schedule.
Does the CLFS amount vary by locality or setting?
No. The national amount is the same across states and 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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