UB04 Field 77: Operating ID

Overview

UB04 Field 77 (Box 77) is labeled Operating ID and captures both the name and identification number(s) of the operating provider – the individual with primary responsibility for performing a surgical procedure. ^[1] designates this field as situational: it must be reported when a surgical procedure code is listed on the claim; otherwise, the field must be left blank. The required identifiers include the National Provider Identifier (NPI) and, optionally, a secondary identifier such as the state license number (qualifier 0B). ^[2] confirms this situational requirement. Maryland Medicaid’s instructions further specify that the field should contain the Operating Physician National Provider Identification (NPI) Number/QUAL/ID, emphasizing the NPI as the primary identifier. ^[3] The field is applicable for both inpatient and outpatient claims whenever a surgical procedure is part of the billing episode.

When to Use

Field 77 is situational per CMS guidelines. It must be completed only when a surgical procedure code is present on the claim. ^[1] states: “Required when a surgical procedure code is listed on this claim. If not required, do not send.” The field identifies the licensed practitioner who performed the surgery; this is typically the primary surgeon. For non-surgical services (e.g., medical admissions, observation, or diagnostic procedures without surgery), the field must be left blank. Maryland Medicaid reinforces that the field expects the NPI of the operating physician. ^[3] Providers must ensure the NPI matches the surgeon’s record and that any secondary identifier (e.g., state license number) uses the correct qualifier 0B. The field applies to both inpatient and outpatient claims when surgical procedures are billed.

Step-by-Step Claim Example

Scenario: A 72-year-old male is admitted for a total hip arthroplasty (CPT 27130) performed by Dr. Jane Smith. The claim includes revenue code 360 (Operating Room Services) and procedure code 27130. No other surgical procedures are billed.

Step 1 – Verify surgical procedure is present – The presence of CPT 27130 triggers the situational requirement for Field 77.
Step 2 – Obtain Dr. Smith’s credentials – NPI: 1234567890; State License Number: MA-98765.
Step 3 – Populate Field 77 – Enter the operating provider’s name as “SMITH, JANE”. In the identifier portion, enter “1234567890” with qualifier NPI (or XX per payer preference). Per CMS, a secondary identifier using qualifier 0B for the state license number may be appended. ^[1]
Step 4 – Complete remaining required fields – Field 76 (attending physician), Field 74 (principal procedure code with date), and revenue codes as appropriate.
Step 5 – Submit claim – The UB04 hard copy or electronic equivalent must contain the NPI in the proper segment (e.g., loop 2310C in 837I).

If the claim were for a medical admission with no surgery, Field 77 would be left empty. ^[2]

Common Mistakes & Audit Red Flags

1. Omitting Field 77 when surgery is present – This is a frequent compliance gap. ^[1] explicitly requires it; missing the field can trigger claim denial or audit requests.
2. Including Field 77 for non-surgical claims – Adding an operating provider when no surgery was performed is incorrect and may indicate upcoding or data entry error.
3. Incorrect NPI or mismatched identity – The NPI must belong to the surgeon listed in the operative report. Using the attending physician’s NPI instead of the operating surgeon’s is a common mistake that leads to audit flags.
4. Wrong qualifier for secondary identifier – If a state license number is used, the qualifier must be 0B per CMS. Using an unapproved qualifier may cause the ancillary identifier to be ignored or rejected. ^[1]
5. Inconsistent procedure code across fields – If Field 77 is populated, the surgical procedure code in Field 74 must align with the operating provider’s specialty and documentation. Auditors cross-reference Fields 74 and 77 to validate medical necessity.

Related Codes/Fields

Field Number	Field Name	Relationship to Field 77	Source
76	Attending Provider	Identifies the physician responsible for overall patient care; may differ from surgeon.	[1]
74	Principal Procedure Code	Lists the surgical procedure the operating provider performed; triggers Field 77.	[3]
78	Other Physician ID	Used for other assisting physicians; not to be confused with the primary operating provider.	[3]
79	Other Physician ID	Additional physician identifiers (e.g., the anesthesiologist or assistant surgeon).	[3]
64	Document Control Number	Used for tracking; not directly related but often cross-referenced in claim audits.	[3]

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References

[1] CMS Chapter 25 — https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c25.pdf

[2] CMS R1915CP — https://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/downloads/R1915CP.pdf

[3] Maryland Medicaid FL 77 — https://health.maryland.gov/mmcp/provider/Documents/ffs-billing/UB04-Hospital-Billing-Instructions%20%281%29.pdf