CPT code 82042: Fluid albumin, CSF or amniotic fluid2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Quantitative albumin testing of cerebrospinal or amniotic fluid is reported when either specimen, rather than serum or urine, is analyzed.
Medicare pays $7.78 for 82042 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
$7.78
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
- QW · CLIA-waived test
- $7.78
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 82042 covers
This test measures albumin quantitatively in cerebrospinal fluid (CSF) or amniotic fluid. Results quantify albumin concentration in the selected fluid. Select it based on the specimen source; serum and urine albumin have separate codes. Amniotic-fluid albumin is analyzed as a distinct fluid chemistry test. Clinical laboratories analyze the submitted specimen.
Report one unit for each specimen tested. CMS also lists a QW version for performance by a site holding a CLIA certificate of waiver. Medicare pays this test only under the CLFS; it is excluded from physician fee schedule payment. The 2026 national CLFS amount is $7.78, unchanged since 2020. One national amount applies across states and localities, with no geographic or office/facility adjustment.
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 82042
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 82042. 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 82042 with status X (excluded by statute), so the test itself is paid only from the CLFS.
CLIA-waived version (QW)
CMS also lists 82042 with modifier QW, the version labs holding a CLIA certificate of waiver bill. It pays $7.78.
82042 on the lab fee schedule since 2020
82042 · CLFS 2026 Q4 (current)
$7.78
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.
82042 compared with similar tests
- 82040Albumin assayBlood specimen$4.95
- Use 82040 for serum albumin. Use 82042 when the specimen is CSF or amniotic fluid.
- 82043Urine albuminQuantitative measurement$5.78
- Use 82043 for quantitative urine albumin; 82042 is for quantitative albumin in CSF or amniotic fluid.
- 82044Urine albuminSemiquantitative$6.23
- 82044 is for semiquantitative urine albumin. 82042 is for quantitative testing of CSF or amniotic fluid.
82042 billing questions
When should I report 82042 instead of a serum or urine albumin code?
Report 82042 for quantitative albumin testing of CSF or amniotic fluid. Serum albumin and urine albumin have separate codes.
How many units should be reported?
Report one unit for each specimen tested.
When is modifier QW relevant?
CMS lists a QW version for a site holding a CLIA certificate of waiver that performs the test.
Does Medicare pay 82042 under the physician fee schedule?
No. Medicare pays the test under the CLFS, with one national amount across localities and no office/facility adjustment.
Can 82042 be used for quantitative urine albumin?
No. Use 82043 for quantitative urine albumin; 82042 is for CSF or amniotic-fluid albumin.
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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