HCPCS Q4166: Wound matrixMedicare rate & RVUs

Medicare pays $127.26 for Q4166 nationally in the office. Local office rates run $109.31–$183.51.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What Q4166 covers

Cytal is an extracellular matrix wound product derived from porcine urinary bladder tissue. A wound-care clinician may apply it to a prepared wound bed, including in the treatment of chronic wounds such as diabetic foot or venous leg ulcers. The product amount is reported by the square centimeter, rather than by the number of wounds or a time increment.

Report Q4166 with the primary wound application procedure for the same treatment, using documentation that identifies Cytal, the treated wound site, and the quantity applied in square centimeters. CMS classifies this as an add-on code: it must be billed with a primary procedure and is paid within that procedure's global period. CMS also identifies it as technical-component-only, with interpretation covered by a separate code rather than this line. The application service and the Cytal material are distinct reported items.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where Q4166 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

Q4166 rates by state

Office rate range in each state. Select a state to see its payment localities.

How the Q4166 rate is calculated

Each of Q4166’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for Q4166

The CMS indicators that decide how Q4166 is paid alongside other services.

Q4166 compared with similar codes

How to choose

Q4165Wound matrix

Q4165 identifies Keramatrix or Kerasorb. Q4166 is specific to Cytal; select according to the product actually furnished.

Q4167Wound product

Q4167 identifies TruSkin, not Cytal. Both are area-based wound product codes, but the product determines which code applies.

15271Skin substitute graft

15271 reports the wound application service for qualifying trunk or extremity sites. Q4166 reports the Cytal material and must accompany a primary procedure.

Codes related to Q4166

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates