CPT Code 87591

Key takeaways

CPT Code 87591 describes qualitative detection of Neisseria gonorrhoeae (gonorrhea) by nucleic acid amplification test (NAAT) using an amplified probe technique

87591 is paid under the Clinical Laboratory Fee Schedule at a single 2026 national rate of $35.09, with no facility split or locality adjustment

87591 is routinely co-billed with CPT 87491 (chlamydia NAAT) and CPT 87661 (trichomonas NAAT) in STI panels, where modifier 59 often prevents bundling denials

Practice management software like Pabau connects CPT code selection, documentation, and electronic claim submission, which cuts miscoding risk on STI panel claims

CPT Code 87591 is the billable code for qualitative detection of Neisseria gonorrhoeae by nucleic acid amplification test (NAAT), amplified probe technique. Medicare pays it under the Clinical Laboratory Fee Schedule, at one national rate with no locality adjustment. The code and the diagnosis pairing decide what gets paid, so a denial almost always starts in the chart rather than in the fee schedule.

This reference guide covers the official descriptor, the 2026 fee schedule, the ICD-10-CM crosswalk, documentation requirements, companion codes, and the denials that follow each. It draws on AMA CPT code set guidance and CMS payer policy.

CPT Code 87591: Description and clinical overview

Three CPT codes describe gonorrhea nucleic acid testing, and the methodology on the lab report decides which one applies. 87591 is the code for a qualitative amplified probe NAAT, which covers nearly every platform in current use.

NAAT is now the gold-standard detection method for gonorrhea according to AAPC coding guidance. The amplified probe technique copies target DNA sequences until even a low bacterial load is detectable. That makes it far more sensitive than culture-based methods. Because the test is qualitative, it reports a positive or negative result only, with no bacterial count.

CPT Code 87591 Medicare reimbursement rate and fee schedule 2026

Medicare pays CPT Code 87591 under the Clinical Laboratory Fee Schedule (CLFS), not the Physician Fee Schedule. That distinction decides everything else about the rate. A CLFS test carries one national amount, so there is no facility versus non-facility split, no national limiting charge, and no geographic adjustment.

National pricing replaced local carrier pricing for lab tests in 2018 under PAMA, which is why 87591 pays the same in every MAC jurisdiction. Verify the figure in the CMS clinical laboratory fee schedule files before you set your own fee schedule, because the rate updates each January.

One national rate makes the 87591 line easier to maintain than a physician fee schedule code. There is no locality file to reload each January and no facility variant to map against a place of service. What still needs attention is the payer mix, since a commercial contract sets its own figure for the same test.

ICD-10-CM diagnosis codes for CPT Code 87591

Pairing CPT Code 87591 with the correct ICD-10-CM diagnosis code is what establishes medical necessity. Payers validate the diagnosis-to-procedure match on every claim. Two categories of codes apply: active infection codes in the A54 series, and the preventive screening encounter code Z11.3.

On a preventive STI screening claim, Z11.3 is the primary diagnosis code. It marks the encounter as screening, which is what triggers the cost-sharing waiver on a commercial plan under ACA Section 2713. Medicare pays clinical lab tests at 100% of the fee schedule either way. The pairing matters there for medical necessity, not for the patient’s bill.

An A54 code on an asymptomatic screening claim invites a medical necessity denial. On a commercial plan it can also push a deductible back onto the patient. The full ICD-10-CM code index covers the screening and infection codes that pair with the rest of an STI panel. Verify assignments each year against the CMS ICD-10 code update files.

Billing guidelines and documentation requirements

Every CPT Code 87591 claim needs documentation that establishes medical necessity. Missing documentation is the fastest path to a denial. The requirements differ slightly between diagnostic testing in a symptomatic patient and preventive screening in an asymptomatic one.

• Medical necessity documentation: On a diagnostic claim with an A54 diagnosis, the chart note must record the clinical indication. That means symptoms, risk factors, or the clinician’s rationale for ordering the NAAT. On a screening claim with Z11.3, the note must support at-risk status. That covers multiple sexual partners, a prior STI, or sexually active females 24 years and younger per USPSTF criteria.
• Order from a qualified provider: The test must be ordered by the treating provider. Lab-initiated orders with no referencing provider are a common denial trigger.
• Specimen type documented: The collection site should appear in the chart note or the lab requisition, whether that is endocervical, urethral, or pharyngeal. Some payers require the specimen source on the claim itself.
• Place of service (POS) code: POS 11 (office) and POS 81 (independent laboratory) are the most common, and facility claims use POS 22. The CLFS rate does not change with POS, but a code that contradicts the ordering record can still draw a rejection.
• Modifier 59 (or X-modifiers): Billing 87591 alongside companion STI codes in the same session may require modifier 59 to override NCCI bundling edits. Verify current NCCI edits before applying it, since some MAC jurisdictions prefer the more specific X{EPSU} modifiers.
• Frequency limitations: Medicare covers gonorrhea NAAT screening once per year for at-risk beneficiaries. Billing more often without medical necessity documentation results in an automatic denial.

Structured documentation in the patient chart maps to the fields payers audit, which makes appeals and prior authorization responses faster. Make sure every 87591 line carries the specimen source, the ordering provider NPI, and the diagnosis code that justifies it.

Medicare coverage for CPT Code 87591: Preventive STI screening

Medicare covers gonorrhea NAAT testing as a preventive service under the sexually transmitted infections (STI) screening benefit. Noridian Medicare’s LCD and CMS preventive services policy set the parameters, and claims that fall outside them are denied on medical necessity.

• Eligible beneficiaries: Medicare beneficiaries at increased risk for STIs. That includes a history of STIs, multiple sexual partners, or exchanging sex for money or drugs. Sexually active females 24 years and younger also qualify under USPSTF Grade B criteria.
• Frequency limit: Once per year. Billing more often without a documented change in clinical status, such as a new exposure or new symptoms, will draw a medical necessity denial.
• Cost-sharing waiver: When billed correctly with Z11.3 under the ACA Section 2713 preventive services mandate, patient cost-sharing is waived for Medicare Advantage plans. Confirm waiver status with your specific MAC, since the post-Braidwood ruling created some coverage uncertainty for commercial plans.
• Companion code coverage: CPT 87491 (chlamydia) is frequently covered alongside 87591 in the same STI screening encounter. Billing both in the same session with correct modifier usage is recognized by CMS and by MACs including Noridian.
• HIBC billing context: High intensity behavioral counseling (HIBC) for STI prevention is billed separately when it happens in the same encounter. It does not replace or bundle with 87591.

Companion codes: Billing 87591 alongside 87491 and 87661

STI panels routinely test for several pathogens in one clinical encounter. CPT Code 87591 is almost always ordered alongside CPT 87491 and CPT 87661. The first covers chlamydia and the second covers trichomonas, both by amplified probe NAAT. How the three codes interact on a single claim is where panel billing goes wrong.

The biggest bundling risk comes from the specimen. Some payers treat 87491 and 87591 as a combination unit when both results come from one sample. If your lab runs a dual-target chlamydia and gonorrhea assay, check whether CPT 87801 applies instead of two separate lines. Billing both individual codes for a combined panel is a miscoding error that payers increasingly audit.

CPT 87591 vs 87590 and 87592: Choosing the right gonorrhea code

Three CPT codes describe gonorrhea NAAT testing, and picking the wrong one leads straight to a denial or an audit. The distinction comes down to the test methodology, not the organism detected.

Nearly every commercial NAAT platform in use today runs an amplified probe assay. Abbott Alinity, Hologic Panther and Roche cobas all fall into that group, which makes 87591 the correct gonorrhea code in most practices. Check your reference lab’s test report for “amplified” or “NAAT” in the methodology line before you assign the code. A report that says “DNA probe” with no amplification takes 87590.

The two decisions behind an 87591 claim run on separate inputs, and the chart below keeps them apart.

Common billing errors and denial reasons for CPT 87591

Gonorrhea NAAT claims fail in a predictable set of ways. Catching them before submission costs far less than working them after the remittance arrives. Most 87591 denials fall into one of five categories.

• Missing or mismatched ICD-10 code: An A54 code on a preventive screening claim, or Z11.3 on a symptomatic patient who needed a diagnostic code. Either way the claim comes back as a medical necessity denial. Read the clinical context before assigning the diagnosis.
• Bundling with 87491 without modifier 59: BCBS NC and BCBS RI tightened their STI panel policies in 2025. Both now enforce NCCI bundling edits more strictly. A missing modifier 59, or the appropriate X-modifier, on the lower-value code leaves the second code denied as incidental. Check current NCCI edits before each claim run.
• Exceeding frequency limits: Medicare permits one preventive gonorrhea screening per beneficiary per year. A second screening inside 12 months is denied automatically without a documented change in clinical status, such as a new exposure or new symptoms.
• Wrong code for the assay type: Billing 87591 when the lab report describes a non-amplified DNA probe, or billing 87590 for an amplified assay. The methodology section of the lab report is the controlling document.
• Missing CLIA certification number: Every clinical lab claim must carry the CLIA number of the lab that ran the test. A missing or mismatched number is a front-end rejection, so the claim never reaches medical review.

CO-4 and CO-97 are the two CARC codes 87591 denials return most often. CO-4 means the procedure code is inconsistent with the modifier, and CO-97 means payment was included in another service’s allowance. Review the claim for unbundling whenever a CO-97 lands.

Most of those appeals succeed once the corrected claim carries modifier 59 and a diagnosis that supports a distinct service. Name the separate specimen site, or the separate clinical rationale, in the appeal notes.

How claims management software keeps 87591 claims clean

Most sexual health and primary care teams assemble an STI panel claim in pieces. The lab result sits in one system, the chart note in another, and a coder rebuilds the panel by hand from both. Every handoff is a chance to lose the specimen source or the modifier.

Practice management software like Pabau keeps the order, the note, and the claim in one patient record. Its claims management software builds each panel line from the documentation that supports it, then submits electronically through the Claim.MD clearinghouse.

Your coder sees the panel as the clinician ordered it. A missing modifier or an absent specimen source surfaces before submission, rather than on a remittance three weeks later.

Reduce STI claim denials with integrated billing

Pabau connects documentation, CPT code selection, and claim submission in one workflow. Sexual health and primary care teams use it to cut denial rates on STI panel claims.

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Conclusion

Two documents decide an 87591 claim: the lab report and the chart note. Confirm the assay is amplified before you assign the code, then let the encounter type choose between Z11.3 and an A54 diagnosis. Add modifier 59 when the panel carries 87491 or 87661, and hold the annual frequency limit.

One national CLFS rate means the payment side of gonorrhea NAAT billing is predictable, so what a practice loses here is process, not price. Fix the step where the panel gets assembled and the denials go with it. Book a demo to see how Pabau builds STI panel claims from the documentation behind them.

Continue your research

Need to understand the full STI panel claims workflow? What is medical billing walks through the end-to-end revenue cycle process for clinical practices.

Dealing with claim denials on STI codes? Submitting a clean claim covers the pre-submission checklist that prevents the most common denial triggers.

Want to understand how clearinghouse submission works? Claim.MD clearinghouse overview explains how electronic claims reach payers and return ERAs.

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