CPT 77073Radiology

Bone length studies

CPT 77073 covers X-ray imaging to measure and compare bone lengths, typically used to detect growth differences between limbs or assess leg length discrepancies in children and adults.

Showing rates for

National Average

Base Medicare rate

$43.99

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

0.26

PE RVU (NF)

1.07

MP RVU

0.03

Total RVU

1.36

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

Loading bundling edits…

Billing tips

Document specific medical necessity indicating why bone length measurement is required beyond standard skeletal imaging
Impact: Prevents medical necessity denials that account for 35-40% of 77073 claim rejections; ensures full $43.99 reimbursement
Bill 77073 only once per date of service regardless of number of limbs measured, as code describes comprehensive bone length study
Impact: Prevents bundling denials and potential fraud flags; billing multiple units can trigger 100% claim denial and audit
Link appropriate ICD-10 codes for limb length inequality (M21.75x series), growth disturbances (M89.2x), or specific conditions requiring monitoring
Impact: Improves first-pass claim acceptance rate by 25-30% and supports medical necessity requirements
Verify payer-specific age requirements, as some insurers restrict coverage to pediatric patients unless specific adult conditions documented
Impact: Reduces denials for age-related medical necessity; some payers deny 15-20% of adult claims without pre-authorization
Do not bill 77073 with standard extremity X-rays (73000-73660 series) for same anatomical area without modifier 59 and clear documentation
Impact: Prevents NCCI bundling edits that automatically deny 77073 as inclusive; modifier 59 preserves $43.99 payment when appropriate
For serial bone length studies monitoring growth, document interval change and clinical rationale for repeat measurement timing
Impact: Supports medical necessity for follow-up studies; insurers may deny studies performed more frequently than every 6-12 months without justification

Live Field Datano reports yet

Real billers contribute denial patterns and appeal strategies for this code. Once 5+ reports come in, you’ll see live aggregated data here — the only place this exists, free.

Working with CPT 77073?

Get the free Revenue Protection Toolkit — the denial triggers, modifier pitfalls, and bundling conflicts that quietly cost you reimbursement. Instant download.

Help build the field knowledge

MedPayIQ gets smarter as billers contribute. If you've had this code denied, share what happened so others learn from it. Anonymous, no patient info.

Related actions

Frequently asked questions

What is the Medicare reimbursement rate for CPT 77073 in 2025?

The 2025 Medicare national average reimbursement for CPT 77073 is $43.99 for both facility and non-facility settings. This rate is based on 1.36 total RVUs (0.26 work RVU, 1.07 practice expense RVU, 0.03 malpractice RVU) multiplied by the 2025 conversion factor of 32.3465.

Can CPT 77073 be billed bilaterally with RT/LT modifiers?

No, CPT 77073 inherently includes bilateral bone length comparison as part of the procedure definition. The code should be reported only once per date of service regardless of how many limbs are measured. Using RT/LT modifiers is inappropriate and may trigger audit flags, as bilateral comparison is the standard methodology for bone length studies.

What diagnosis codes support medical necessity for CPT 77073?

Common supporting ICD-10 codes include M21.75x series (unequal limb length), M89.2x (disorders of bone development and growth), Q72.x (congenital reduction defects of lower limb), M89.6x (osteopathy after poliomyelitis), and specific codes for growth plate disorders. Pediatric growth monitoring or pre-operative planning for limb length correction procedures also establish medical necessity.

How does CPT 77073 differ from standard extremity X-rays?

CPT 77073 specifically describes bone length measurement studies using calibrated techniques for precise bilateral comparison, while standard extremity X-rays (73000-73660 series) are diagnostic imaging for pathology, fractures, or general anatomy. Bone length studies require special positioning, calibration markers, and quantitative measurement methodology not included in routine skeletal radiography.

How often can CPT 77073 be billed for the same patient?

Frequency depends on payer policy and clinical indication. Most insurers allow repeat bone length studies every 6-12 months for pediatric growth monitoring or post-treatment assessment. More frequent studies require documented change in clinical status, treatment plan modification, or specific surgical planning needs. Serial studies should show interval measurements and clinical rationale for timing.

Can CPT 77073 be billed with an E/M visit on the same day?

Yes, CPT 77073 can be billed with an evaluation and management code on the same date of service without modifier 25, as it is a diagnostic procedure, not a minor procedure. The E/M service should document the separate clinical assessment that led to ordering the bone length study. Ensure medical necessity is clearly established in the encounter documentation.

What modifiers are most commonly used with CPT 77073?

Modifier 26 (professional component) and TC (technical component) are most common when splitting facility and professional charges. Modifier 59 may be necessary when billing with other imaging codes to indicate distinct procedural service and prevent bundling denials. Modifier 76 (repeat procedure) is used rarely when repeat study needed same day due to technical issues requiring complete restudy.