CPT code 77072 – Bone age study

Key Takeaways

CPT Code 77072 describes a single bone age study radiograph, including radiologist interpretation and written report, used to assess skeletal maturity.

Bill Modifier 26 when the radiologist provides interpretation only; bill Modifier TC for the technical component; bill globally when one entity owns both.

Supported ICD-10-CM codes include E34.30 (short stature due to endocrine disorder), M89.20 (growth retardation), and Z00.129 (routine child health exam). Verify them against your MAC’s LCD.

Pabau’s claims management software checks 77072 claims for missing required details and submits them through Claim.MD with real-time eligibility checks.

CPT Code 77072: Official descriptor and procedure overview

CPT Code 77072 is a diagnostic radiology code defined by the American Medical Association as: Radiologic examination, bone age studies. It covers a single plain-film radiograph, typically a posteroanterior (PA) view of the left hand and wrist. The image is used to compare skeletal age with chronological age.

The procedure is most commonly ordered in pediatric and pediatric endocrinology settings. A radiologist evaluates the ossification centers of the carpal bones and phalanges against a reference atlas, most often the Greulich-Pyle atlas. The radiologist then produces a written interpretation report stating the estimated bone age.

The code sits in the Bone/Joint Studies subsection (77071-77086) of the CPT Radiology section. It shares that subsection with the osseous survey codes (77074, 77075) and the bone density code 77080. It is a global service code. It typically bundles the technical component (acquiring the image) and the professional component (radiologist interpretation) unless split with Modifier 26 or TC.

What CPT 77072 includes and what it does not cover

Scope clarity prevents the most common upcoding and bundling errors on this code. Bill CPT Code 77072 when the sole purpose is skeletal maturity assessment via a single bone age radiograph with written report.

• Included: Single radiograph (typically left hand/wrist PA view), radiologist interpretation, written bone age report
• Not included: Multiple-view skeletal surveys (use 77074 or 77075 instead)
• Not included: DXA bone density measurement (use 77080 instead)
• Not included: CT or MRI-based bone studies (separate code families)
• Not included: Orthopedic or fracture imaging of the hand/wrist (use 73100 or 73110 series)

A radiograph ordered primarily to assess a suspected fracture does not qualify for 77072, even if the left hand/wrist is the anatomical site. The clinical intent must be skeletal maturity assessment.

Clinical indications: When a bone age study is ordered

Medical necessity for CPT Code 77072 rests on documented clinical conditions that require skeletal maturity assessment. Payers apply their MAC’s local coverage determination (LCD) to evaluate whether the ordering diagnosis supports the study.

• Short stature or growth failure: The most common indication. Bone age helps distinguish constitutional delay from pathological growth hormone deficiency.
• Precocious puberty: Early puberty accelerates bone maturation; bone age confirms advancement beyond chronological age.
• Delayed puberty: Bone age lag supports endocrine evaluation and treatment planning.
• Suspected growth hormone deficiency or excess: Bone age is a required component of the diagnostic workup before GH therapy authorization.
• Skeletal dysplasia assessment: Serial bone age studies track progression in known dysplasia syndromes.
• Monitoring during GH therapy: Payers typically cover periodic bone age studies during active treatment to assess treatment response.

Ordering providers should document the specific clinical concern driving the study in the progress note. Vague language (“growth concerns”) without objective data such as height percentile or growth velocity is a common reason MACs flag claims for medical necessity review.

Supported ICD-10-CM diagnosis codes for medical necessity

The table below lists the ICD-10-CM codes most commonly paired with CPT Code 77072. Coverage is subject to your MAC’s LCD – verify the specific list applicable to your jurisdiction before submission. Use the CrossCoder CPT-to-ICD-10 crosswalk tool to confirm current medical necessity pairings.

ICD-10-CM code Z00.129 carries lower coverage certainty and should be supported by objective clinical data in the record. Codes E34.30, E23.0, E30.0, and E30.1 generally align with MAC LCD criteria and are the safest pairings for clean claims.

How the bone age procedure is performed and documented

A properly documented bone age study is the foundation of a payable CPT Code 77072 claim. Incomplete documentation is the second most common denial trigger after incorrect ICD-10 pairing.

1. Patient positioning: The patient’s left hand and wrist are placed palm-down on the imaging plate. The left hand is the standard per the Greulich-Pyle atlas methodology; using the right hand without documented reason is a documentation gap.
2. Single PA radiograph acquisition: One posteroanterior view is obtained. 77072 covers a single bone age study, not a series of views. Multiple views of different anatomical sites at the same encounter indicate a different code.
3. Radiologist interpretation: The radiologist compares the patient’s ossification pattern against the Greulich-Pyle atlas (or Tanner-Whitehouse scale). The interpretation must state the estimated bone age in years and months.
4. Written report: A separate, signed, dated written report must be generated. It must document the method used, the comparison atlas, the bone age estimate, and the clinical correlation. A verbal interpretation without a signed written report does not support billing.
5. Report retention: The written report and the radiographic image must be retained per state law and payer requirements. Some MACs request the report during claim audits.

For split-component billing (radiologist bills professional component separately from the facility’s technical component), each party must document their respective service independently. The radiologist’s signed report is the supporting document for Modifier 26 billing.

CPT Code 77072 reimbursement: Medicare rates and fee schedule

Medicare reimburses CPT Code 77072 under the CMS Medicare Physician Fee Schedule (MPFS). Rates vary by geographic locality and setting. Always verify current figures in the MPFS Look-Up Tool, as rates are updated annually with each Physician Fee Schedule final rule.

These are approximate national non-geographically adjusted figures. Actual payment differs by MAC locality using the Geographic Practice Cost Index (GPCI). The FastRVU 2026 lookup tool provides current work RVU (wRVU), practice expense RVU (peRVU), and malpractice RVU values by locality. Workers’ compensation rates are state-specific and updated independently of CMS; a rate applicable in Pennsylvania will differ from Oregon’s schedule.

Practices using Pabau can submit 77072 claims electronically through Pabau’s Claim.MD integration, its US clearinghouse partner. The integration also runs real-time eligibility checks and brings electronic remittance advice (ERA) back into Pabau.

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Modifiers for CPT Code 77072: TC, 26, and applicable options

Correct modifier use determines whether the claim pays in full, splits correctly between radiologist and facility, or denies entirely. The three modifier scenarios for CPT Code 77072 are global, professional, and technical.

Payers cross-reference the modifier against the place-of-service (POS) code. A claim with no modifier billed to hospital outpatient POS 22 is typically processed as a professional component claim. It then pays less than a global claim at POS 11 (office) would receive.

CPT 77072 vs related radiology codes: Choosing the right code

Upcoding from 77072 to 77074 or 77075 is a common audit risk in pediatric radiology billing. The distinction between these codes is procedural, not merely one of clinical complexity.

The 77072/77075 bundling edit reflects NCCI logic. A complete skeletal survey already images the hand and wrist, so a simultaneous bone age study is considered duplicative. Modifier 59 can override this edit only when the bone age study was performed at a genuinely distinct session with separate clinical documentation. Verify the current NCCI edit pairing in the quarterly CMS edit file before applying the override.

Prior authorization requirements for CPT Code 77072

Prior authorization for CPT Code 77072 is not universal. Medicare fee-for-service does not currently require prior auth for this code. The picture changes significantly with Medicare Advantage plans and commercial payers.

Completing insurance eligibility verification before scheduling is the fastest way to identify PA requirements at the patient level.

• Medicare Advantage: Many MA plans apply prior authorization requirements to diagnostic imaging that traditional Medicare does not. Check the specific plan’s PA list annually, as requirements change with each contract year.
• Commercial payers: Large carriers (UHC, Aetna, BCBS affiliates) frequently require PA for bone age studies when the ordering provider is not a pediatric endocrinologist. Prior auth requirements are more common when the study is ordered in the context of GH therapy initiation.
• Medicaid: PA requirements vary by state Medicaid program. Managed Medicaid organizations often apply more stringent PA criteria than fee-for-service Medicaid.

A PA request should include the ordering provider’s clinical note documenting the growth concern. Add height and weight measurements with percentile data and growth velocity over at least six months. If serial monitoring is the indication, include any prior bone age results. Payers may deny PA if the clinical note does not quantify the growth abnormality.

Common denial reasons for CPT Code 77072 and how to avoid them

Most 77072 denials fall into six categories. Systematic denial management workflows built around these patterns prevent the majority of revenue loss.

• Non-covered diagnosis code: The paired ICD-10-CM code does not appear on the MAC’s LCD-covered diagnosis list. Fix: audit your ICD-10 pairings quarterly against the current LCD for your jurisdiction. Use E34.30 or E23.0 as primary when appropriate.
• Missing radiologist written report: The claim is submitted without a signed, dated written interpretation on file. Fix: configure your billing workflow to hold 77072 claims until the written report is documented in the chart.
• Incorrect or missing modifier: Global billing at a facility POS, or missing Modifier 26 when the radiologist does not own the equipment. Fix: implement a modifier validation rule that checks POS code against the modifier submitted before claim release.
• Bundling conflict with same-date skeletal survey: 77072 billed on the same date as 77075 without Modifier 59 or without separate documentation supporting a distinct encounter. Fix: set up an NCCI edit alert in your billing system that flags the 77072 + 77075 code pair at charge entry.
• Prior authorization not obtained: The payer required PA and the claim arrives without an authorization number. Fix: add a PA check step to the scheduling workflow for all 77072 orders under non-traditional-Medicare payers.
• Incorrect place-of-service code: POS 22 (hospital outpatient) submitted when the service was provided in an office setting. Fix: verify POS at point of scheduling and cross-check against the appointment location before billing.

Reviewing denial codes in medical billing helps staff interpret the CARC/RARC codes on remittances. Each denial can then go to the correct corrective action instead of a generic rework queue.

Billing tips: Avoiding unbundling and upcoding errors

OIG compliance guidance for physician practices and clinical laboratories identifies unbundling and upcoding as primary audit triggers. Radiology billing compliance for 77072 requires three specific controls.

• Code pair alert for 77072 + 77074/77075: Configure your billing software to flag this code pair at charge entry. The NCCI edit applies to 77072 billed with 77075 on the same date for the same patient. Submitting both without a distinct clinical justification and Modifier 59 is an unbundling error and an audit risk.
• Do not upcode based on image count: If a bone age study captures two views of the left hand, 77072 is still the correct code. The additional view does not elevate the procedure to a limited osseous survey (77074). The clinical purpose – bone age assessment – governs the code, not the number of exposures.
• Documentation checklist before billing: The written radiologist report is present and signed. The ICD-10 code on the claim matches the indication documented in the ordering provider’s note. The modifier reflects the actual billing relationship between radiologist and facility. PA authorization number is captured in the claim if required.

Pabau’s claims management software checks each 77072 claim for missing required details, such as authorization codes, before it is sent. The Claim.MD integration handles claim submission, real-time eligibility checks, and ERA retrieval. Denial patterns then surface in the dashboard rather than in a stack of paper remittances.

Conclusion

CPT Code 77072 is a low-volume but denial-prone code, and its claim errors cluster in predictable places. They are a wrong ICD-10 code, a missing written report, a modifier/POS mismatch, and an unbundled same-day skeletal survey. None of these require complex fixes; they require consistent workflow controls applied before the claim leaves the practice.

Pabau’s integrated clean claim workflow checks each claim for missing required details, then submits it through Claim.MD with real-time eligibility checks and ERA tracking. To see how it works for your practice, book a demo.

Continue your research

Need to understand how clearinghouse claim validation works? Our Claim.MD clearinghouse guide explains how electronic claim scrubbing catches errors before payer submission.

Looking for a reference on reading remittance denial codes? Electronic remittance advice (ERA) explained covers how to interpret CARC and RARC codes on 835 files.

Billing for related radiology services? IVF CPT codes reference covers another specialty procedure code set with similar documentation and modifier requirements.

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