Lab & pathology
87491 — Infectious agent detection by nucleic acid; Chlamydia trachomatis, amplified probe technique
A highly sensitive molecular (PCR/NAAT) test that detects Chlamydia trachomatis DNA or RNA in a specimen (urine, cervical, or vaginal swab) to diagnose chlamydia infection.
- Typical setting: Hospital lab, reference lab
- National avg charge (illustrative): $25–$55 Medicare allowed (CMS CLFS); $40–$130 commercial; varies by region
- Most-disputed reason: Billing 87491 separately when it is included in a combined chlamydia/gonorrhea dual test panel (87800 series) that was ordered — verify whether the combined code was used
What it means
What 87491 actually means
A highly sensitive molecular (PCR/NAAT) test that detects Chlamydia trachomatis DNA or RNA in a specimen (urine, cervical, or vaginal swab) to diagnose chlamydia infection. This amplified probe method is more accurate than older culture or antigen methods.
Common errors with this code
What goes wrong on real bills.
Most bills that look correct still contain at least one of these issues. Up to 49% of medical bills contain errors (CFPB).
- Billing 87491 separately when it is included in a combined chlamydia/gonorrhea dual test panel (87800 series) that was ordered — verify whether the combined code was used
- CCI edit conflicts: 87491 and 87591 together may have bundling edits with certain molecular panel codes (e.g., 81381); modifier may be required if genuinely separate tests
- Billing without appropriate STI screening or diagnostic ICD-10 code documentation, especially when ordered as part of an annual well-woman visit
If you see 87491 on your bill
Three steps before paying.
1. Get the itemized bill. If your statement only shows a summary, request the CPT-level itemized bill before paying. Generate the request language →
2. Cross-check against the EOB. Compare what your insurer's Explanation of Benefits says you owe versus what the hospital is asking. They disagree more often than people think. Read the bill-vs-EOB guide →
3. Run a free Bill Scan. Upload the bill (and EOB if you have it) and BillBusted will flag the most likely issues with this specific code in your specific state. Run free scan →
Related codes
Other codes in this category.
People who land on 87491 often also see these adjacent codes on the same bill.
CPT
80050 — General health panel; includes CBC w/diff, CMP, TSH
Lab — check for unbundling and duplicate billing.
CPT
80051 — Electrolyte panel; CO2, chloride, potassium, sodium
Lab — check for unbundling and duplicate billing.
CPT
80053 — Comprehensive metabolic panel
If individual blood tests are also on your bill, you may have an unbundling error.
CPT
80055 — Obstetric panel; CBC w/diff, HBsAg, rubella Ab, syphilis, RBC Ab screen, ABO/Rh
Lab — check for unbundling and duplicate billing.
CPT
80061 — Lipid panel (cholesterol)
If you see HDL or LDL listed separately next to 80061, that's unbundling.
Related BillBusted guides
Plain-English reads if you see 87491 on a bill.
87491 FAQ
Plain-English answers.
What does 87491 usually cost?
$25–$55 Medicare allowed (CMS CLFS); $40–$130 commercial; varies by region. Costs vary by region, payer contract, and whether the service was performed in a hospital outpatient department (which adds a facility fee) versus a free-standing clinic.
What's the most common billing error on 87491?
Billing 87491 separately when it is included in a combined chlamydia/gonorrhea dual test panel (87800 series) that was ordered — verify whether the combined code was used
What should I do if I see 87491 on my bill?
Request the itemized bill and the matching EOB from your insurer. Compare the units/quantity billed against what you actually received. Run a free BillBusted scan to flag the most likely errors specific to 87491 before paying.
Don't pay 87491 blindly.
The free scan tells you in under 60 seconds whether this charge looks reasonable for your situation.