CPT 79300Radiology

Nuclr rx interstit colloid

CPT code 79300 covers the administration of radioactive colloid material directly into tissue spaces (interstitial) for therapeutic purposes, typically used to treat certain cancers or conditions requiring localized radiation therapy.

Showing rates for

National Average

Base Medicare rate

$60.81

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

1.6

PE RVU (NF)

0.26

MP RVU

0.02

Total RVU

1.88

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

NCCI bundling edits

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Billing tips

Separately bill for the radiopharmaceutical supply using appropriate HCPCS codes (A9699 for unlisted radiopharmaceutical if no specific code exists) in addition to CPT 79300 for the administration service
Impact: Radiopharmaceutical costs can range from $500-$5,000+ depending on isotope and dose; failure to bill separately results in significant revenue loss
Document precise anatomic location, isotope type, dose administered (in millicuries or microcuries), and radiation safety precautions to support medical necessity and prevent denials
Impact: Complete documentation reduces denial rate by approximately 40% and supports appeals for initially denied claims
Bill imaging guidance procedures (ultrasound 76942, CT 77012, fluoroscopy 77002) separately when used for needle placement, as these are not bundled with 79300
Impact: Additional $50-$200 per imaging guidance code, representing 80-330% increase over base 79300 reimbursement
Verify that facility has current NRC or Agreement State license for therapeutic radiopharmaceutical use and that physician is listed as authorized user before performing procedure
Impact: Performing without proper authorization can result in 100% claim denial, regulatory penalties, and potential fraud investigation
For hospital outpatient settings, ensure facility bills appropriate revenue code (0342 for radiopharmaceutical therapy) on UB-04 to capture full technical reimbursement
Impact: Incorrect revenue code can delay payment by 30-60 days and may result in incorrect payment bundling
When treating malignant effusions, link appropriate ICD-10 codes for both the effusion (J91.0, J91.8) and underlying malignancy to establish medical necessity

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Frequently asked questions

What is the Medicare reimbursement rate for CPT code 79300 in 2025?

The 2025 Medicare national average reimbursement rate for CPT 79300 is $60.81 for both facility and non-facility settings. This rate is based on 1.88 total RVUs multiplied by the 2025 conversion factor of 32.3465. Actual reimbursement may vary by geographic locality based on the GPCI adjustments in your area.

Can CPT 79300 be billed with an E/M code on the same day?

Yes, but only if the E/M service is significant and separately identifiable from the procedure planning, and modifier 25 must be appended to the E/M code. Best practice is to perform the consultation and treatment planning on a separate date to avoid documentation burden and potential denials for bundling.

What radiopharmaceuticals are typically used with CPT code 79300?

Common radiopharmaceuticals for interstitial administration include Phosphorus-32 (P-32) chromic phosphate for cystic tumors and effusions, Gold-198 (Au-198) colloid, and Yttrium-90 (Y-90) silicate. The specific isotope selection depends on tumor type, location, and desired radiation penetration characteristics. The radiopharmaceutical must be billed separately using appropriate HCPCS codes.

Is prior authorization required for CPT 79300?

Prior authorization requirements vary by payer. Medicare typically does not require prior authorization for 79300, but Medicare Advantage plans frequently do. Commercial payers often require prior authorization for all therapeutic radiopharmaceutical procedures due to the high cost of isotopes and specialized nature of treatment. Always verify with the specific payer before scheduling.

How do I bill for the imaging guidance used during interstitial colloid administration?

Imaging guidance is billed separately from CPT 79300 using appropriate codes: 76942 for ultrasound guidance, 77002 for fluoroscopic guidance, or 77012 for CT guidance. These codes are not bundled with 79300 per NCCI edits, allowing separate reimbursement when medically necessary and properly documented.

What documentation is needed to prove medical necessity for CPT 79300?

Documentation must include: specific diagnosis requiring interstitial radiation, evidence of failed conventional therapies or rationale why interstitial approach is preferred, multidisciplinary treatment planning notes, imaging studies showing tumor characteristics, expected therapeutic benefit, and radiation oncology consultation. For malignant effusions, document recurrence after drainage or pleurodesis attempts.

What are the RVU values for CPT code 79300 in 2025?

The 2025 RVU values for CPT 79300 are: Work RVU 1.6, Practice Expense RVU 0.26 (both facility and non-facility), and Malpractice RVU 0.02, totaling 1.88 RVUs. These values reflect the specialized expertise required for therapeutic radiopharmaceutical administration and associated radiation safety protocols.