Obstetric ultrasound billing: complete, limited, and antenatal testing.
Obstetric ultrasound denies for frequency more than almost any other OB code family, and the reason is nearly always the same: a complete study billed a second time without a new medical indication behind it. The complete-versus-limited distinction — 76801/76805 versus 76815/76816 — is what a payer's claims logic checks first, before it ever looks at the clinical note. This guide covers every code in the family, exactly what documentation supports a legitimate repeat complete scan, and where the biophysical profile and non-stress test codes get double-billed.
Key takeaways
- 76801/76805 (complete) is intended once per pregnancy absent a new indication. A second complete study without a chartable new finding is the single biggest driver of CO-151 frequency denials in this family.
- 76815 (limited) doesn't require full-element documentation the way 76801/76805 does. It's built for a specific clinical question at a given encounter, not a complete anatomic survey.
- 76818 already includes the non-stress test. Billing 59025 separately alongside it double-bills a component that's already in the BPP fee; 76819 is the code that excludes the NST.
- No Medicare LCD or NCD specifically governs OB ultrasound frequency — this build searched the CMS Coverage Database directly and found none, consistent with the thin Medicare coverage landscape for OB generally. Frequency limits here are payer-specific medical policy, not a national coverage rule.
The complete-versus-limited distinction
76801 (first trimester) and 76805 (second/third trimester) report a complete fetal anatomic survey, single fetus, and both require full-element documentation — fetal number, cardiac activity, position, amniotic fluid volume, placental location, fetal biometry, and an anatomic survey of the visible structures appropriate to gestational age. Payers expect that documentation to actually be present when the complete code is billed, not just implied by the study having been ordered as "complete." 76815 (limited ultrasound, one or more fetuses) is built differently: it answers a specific clinical question at a given encounter — confirming presentation, amniotic fluid volume, or fetal cardiac activity, for instance — without the full-element documentation a complete study requires. 76816 (follow-up ultrasound) is narrower still: it re-evaluates a specific, previously identified finding, such as a repeat measurement of a known cyst or a placental-location recheck after a prior low-lying placenta finding.
| Code | Service | Frequency logic |
|---|---|---|
76801 | Complete OB ultrasound, first trimester, single fetus (add-on 76802 for each additional fetus) | Once per pregnancy in the first-trimester window, absent new medical necessity |
76805 | Complete OB ultrasound, second/third trimester, single fetus (add-on 76810 for each additional fetus) | Once per pregnancy in the second/third-trimester window, absent new medical necessity |
76815 | Limited OB ultrasound, one or more fetuses | Per encounter, tied to a specific clinical question — no full-element documentation required |
76816 | Follow-up OB ultrasound, re-evaluation of one or more known findings | Per encounter, tied to a specific prior finding being rechecked |
76817 | Transvaginal OB ultrasound | Per encounter, when the transvaginal approach is clinically indicated (early pregnancy, cervical length, or inadequate transabdominal windows) |
59025 | Fetal non-stress test (NST) | Per encounter; not bundled into the global maternity package, but bundled into 76818 when both are performed together |
76818 | Biophysical profile (BPP), with non-stress testing | Per encounter, high-risk antenatal surveillance — includes the NST component |
76819 | Biophysical profile (BPP), without non-stress testing | Per encounter, high-risk antenatal surveillance — use when NST is billed separately or was clinically omitted |
These are CPT codes; the descriptions above are paraphrased, not the AMA's official descriptors — confirm exact language in the CPT Professional edition before building charge-master text off this table.
The CO-151 frequency denial pattern — and what actually supports a repeat complete scan
76801/76805 is intended once per pregnancy per trimester grouping, absent a new medical indication. Most payers' claims logic treats a second complete study, submitted without a documented new finding or change in clinical status, as a duplicate, and it denies as CO-151, frequency. The fix isn't a coding change; it's a documentation practice. The chart has to state the specific new indication driving the repeat complete scan — not just "repeat ultrasound ordered," but the actual clinical finding that made a full anatomic survey medically necessary again, distinct from a routine follow-up of something already known.
Diagnosis codes that plausibly support a repeat complete study, each verified live against the FY2026 ICD-10-CM code set, illustrate the kind of new finding that belongs in the note:
| Code | Description |
|---|---|
O36.5921 | Maternal care for other known or suspected poor fetal growth, second trimester, fetus 1 |
O36.8121 | Decreased fetal movements, second trimester, fetus 1 |
O46.91 | Antepartum hemorrhage, unspecified, first trimester |
A finding like one of these, newly identified since the last complete scan, is what separates a defensible repeat 76801/76805 from a claim that reads as a duplicate. A routine recheck of an existing, already-known finding — say, remeasuring a previously identified marginal cord insertion with no new symptom — belongs on 76816 (follow-up), not a second complete code. This build searched the CMS Coverage Database directly for a national or MAC-specific coverage document governing OB ultrasound frequency and found none active; that's consistent with the thin Medicare coverage landscape for OB/GYN generally, covered in our complete OB/GYN billing guide — Medicare's beneficiary population is rarely pregnant, so frequency limits on this family are set by commercial and Medicaid managed-care medical policy, not a Medicare LCD or NCD. Confirm the specific payer's own frequency policy rather than assuming a Medicare-style rule applies.
Non-stress testing and the biophysical profile: don't double-bill the NST
The BPP family is a common source of an avoidable overpayment-turned-audit-finding, not a denial. 76818 reports the biophysical profile with non-stress testing included as part of the single code — the NST component is already priced into that fee. 76819 reports the biophysical profile without the non-stress test, used when the NST is performed and billed as its own separate line (59025), or when it was clinically omitted from the profile. Billing 59025 as a separate line alongside 76818 bills the non-stress test twice for the same encounter — once inside 76818's own fee, once again as its own code — and that pattern is exactly the kind of thing a post-payment audit catches even when the individual claim paid cleanly at submission.
- Document the specific new clinical indication in the note before billing a repeat complete study (76801/76805).
- Use 76815 or 76816 for a targeted recheck, not a second complete code, whenever the question is narrower than a full anatomic survey.
- Pick 76818 when the NST is performed as part of the profile, and 76819 plus 59025 only when the NST is genuinely billed as its own separate service.
- Confirm the payer's own frequency policy for repeat complete studies rather than assuming a Medicare-style national rule applies.
- Don't reorder a full complete study on a routine interval as a default recheck habit — that's what 76816 exists for.
- Don't bill 59025 alongside 76818 for the same encounter; the NST is already priced into that code.
- Don't submit a repeat 76801/76805 without the specific new finding stated in the note, even when the clinical reasoning behind the reorder was sound.
- Don't assume a limited study (76815) needs the same full-element documentation a complete study does — it doesn't, and requiring it slows the note down for no billing benefit.
Have the ordering physician state the reason for a repeat scan in the order itself, not just in a verbal request to schedule it. An order that says "repeat 76805, new decreased fetal movement" gives the coder what's needed to bill correctly the first time; an order that just says "repeat growth scan" forces the coder to go hunting through the chart after the fact, and that's where the new-indication documentation most often goes missing.
If your practice also owns the ultrasound equipment and a physician outside the group interprets some of these studies, or vice versa, the technical/professional split (TC/26) applies the same way it does across the rest of OB/GYN diagnostic imaging — covered at the specialty level in our complete OB/GYN billing guide.
Losing revenue to OB ultrasound frequency denials?
We'll audit a sample of your recent OB ultrasound claims, name the specific documentation gaps behind your CO-151 denials, and show what's actually recoverable.
Frequently asked questions
Can we bill 76805 twice in the same pregnancy?
Only with a new, documented medical indication for the second complete study. 76801 and 76805 are intended once per pregnancy per trimester grouping absent a new finding; billing the complete code a second time without a chartable reason, such as a new growth concern, decreased fetal movement, or a new bleeding episode, reads to most payers' claims logic as a duplicate and triggers a CO-151 frequency denial. A routine recheck of an existing finding belongs on 76815 or 76816 instead, not a second complete study.
What's the difference between 76815 and 76816?
76815 is a limited ultrasound answering a specific clinical question at a given encounter, such as confirming fetal presentation or amniotic fluid volume, without the full-element documentation a complete study requires. 76816 is specifically a follow-up study re-evaluating a previously identified finding, such as a repeat measurement of a cyst or a placental location recheck. Both are per-encounter, per-finding codes; neither substitutes for 76801 or 76805 when a genuinely new complete anatomic survey is medically necessary.
Do we need a non-stress test order separate from the biophysical profile?
No, when the BPP itself includes the non-stress test. 76818 already reports the biophysical profile with the non-stress test included, billed as one code, one charge. 76819 reports the biophysical profile without the non-stress test component, used when the NST was performed separately or omitted for a documented clinical reason. Billing 59025 (NST) separately alongside 76818 double-bills the non-stress test component that 76818 already includes; 59025 is appropriate as its own line only when a full BPP wasn't performed, or alongside 76819 specifically because that code excludes the NST.
Verify before billing. CPT is a registered trademark of the American Medical Association; codes here are paraphrased, not reproduced from the CPT Professional edition. CPT, HCPCS and ICD-10 codes, coverage policy, and bundling edits change, including annual code-set updates. This page reflects standard industry practice and is provided for general education — it is not a substitute for your own compliance review, your current payer contracts, or the current-year code sets. Confirm requirements against your specific payer mix before submitting claims.