CPT code 87491: Chlamydia test, amplified nucleic acid detection2026 Medicare lab fee · Clinical Laboratory Fee Schedule
Amplified nucleic acid testing detects Chlamydia trachomatis in specimens collected for evaluation or screening of chlamydial infection.
Medicare pays $35.09 for 87491 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
$35.09
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
- $35.09
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 87491 covers
This laboratory assay detects genetic material from Chlamydia trachomatis after target amplification. It is used when evaluating possible genital chlamydial infection and in screening; clinicians commonly order it with testing for gonorrhea. Testing may be performed on urine or swab specimens, with acceptable collection sites and specimens determined by the assay and laboratory. Hospital laboratories, independent laboratories, and eligible waived-testing sites may perform the test.
Report 87491 for amplified detection, rather than a direct-probe code or a quantitative assay. Use a combination code when the performed assay detects both chlamydia and gonorrhea. Modifier QW identifies the CLIA-waived version, which sites holding a CLIA certificate of waiver may perform. Medicare pays from the CLFS at one national amount: the 2026 amount is $35.09, unchanged from 2020 through 2025. The same amount applies nationwide, without locality or office/facility adjustment. The test is excluded from the physician fee schedule and 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 87491
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 87491. 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 87491 with status X (excluded by statute), so the test itself is paid only from the CLFS.
CLIA-waived version (QW)
CMS also lists 87491 with modifier QW, the version labs holding a CLIA certificate of waiver bill. It pays $35.09.
87491 on the lab fee schedule since 2020
87491 · CLFS 2026 Q4 (current)
$35.09
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.
87491 compared with similar tests
- 87490Chlamydia testDirect DNA probe$22.75
- Choose 87490 for direct-probe Chlamydia trachomatis detection; choose 87491 when the assay uses amplification.
- 87492Chlamydia testQuantitative nucleic acid$53.47
- 87491 reports amplified detection, while 87492 is the quantitative assay for Chlamydia trachomatis.
- 87494CT/NG assayMultiplex amplified probe$70.18
- 87494 is the combined chlamydia and gonorrhea test. Use 87491 for amplified chlamydia detection alone.
- 87591Gonorrhea testAmplified DNA probe$35.09
- 87591 detects Neisseria gonorrhoeae, not Chlamydia trachomatis. The assays may be ordered together, or a combined assay may be used.
87491 billing questions
When should 87491 be chosen over 87490?
Use 87491 for amplified detection of Chlamydia trachomatis. Code 87490 describes direct-probe detection.
How does 87491 differ from 87492?
87491 reports amplified detection. 87492 is the quantitative assay in this Chlamydia trachomatis code family.
When is modifier QW appropriate?
Modifier QW identifies the CLIA-waived version. The performing site must hold a CLIA certificate of waiver.
How is separate gonorrhea testing reported?
When separate assays are performed, 87491 reports chlamydia detection and 87591 reports gonorrhea detection. Code 87494 is the combined chlamydia and gonorrhea option when that assay is performed.
How does Medicare pay for 87491?
Medicare pays this test through the CLFS at one national amount that applies across localities and settings. It is excluded from the physician fee schedule.
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
Fee sheets
Put 87491 and the rest of your codes on one sheet
Your codes at your locality, with payer contracts beside Medicare.
Build my fee sheet