UB04 Field 57: Other Provider IDs

Overview

Field 57 (Box 57) on the UB-04 claim form is labeled “Other Provider IDs.” ^[1] includes FL 57 as “Other (Billing) Provider Identifier” in its UB-04 instruction table. However, the Centers for Medicare & Medicaid Services (CMS) has explicitly stated that field 57 is not used for Medicare billing. According to CMS Chapter 25, “FL 57 – Other Provider ID (primary, secondary, and/or tertiary) Not used. Data entered will be ignored.” ^[2] This policy is reinforced by CMS Transmittal R1915CP, which reiterates, “FL 57 – Other Provider ID … Not used.” ^[3] Consequently, the field is designated as “Not Required” for both inpatient and outpatient claims under standard billing guidelines. Providers should be aware that any data entered into field 57 for Medicare claims will be disregarded, and the field is generally left blank unless a specific non-Medicare payer instructs otherwise.

When to Use

Given the CMS directives, field 57 should not be used for Medicare fee-for-service, Medicare Advantage, or most commercial claims that follow CMS billing standards. ^[2] explicitly states that entered data will be ignored, making inclusion unnecessary and potentially confusing during claim processing. However, some state Medicaid programs or unique payer contracts may still expect an alternative billing identifier in this field. For example, Maryland Medicaid lists FL 57 in its UB-04 instruction set as “Other (Billing) Provider Identifier,” though the document does not provide specific guidance on when or what to enter. ^[1] In all other cases, especially for Medicare claims, leave field 57 blank to avoid rejection or data being ignored. Always verify payer-specific billing instructions before completing this field.

Step-by-Step Claim Example

Because CMS instructs that field 57 is not used, the correct approach for the vast majority of claims is to leave it completely blank. ^[2] The following example demonstrates a typical Medicare inpatient claim where field 57 is omitted:

2. Enter the billing provider’s NPI in FL 56 (National Provider Identifier – Billing Provider).
3. Leave FL 57 (Other Provider ID) empty. Do not type, space, or insert any characters.
4. Complete remaining fields as required: FL 58 (Insured’s Name), FL 60 (Insured’s Unique ID), etc.
5. Submit the claim electronically or on paper. No data from FL 57 will be transmitted or processed.

However, since Maryland’s instructions do not detail a specific implementation, providers should contact the payer for clarification. The safest default remains leaving the field blank unless a written directive exists.

Common Mistakes & Audit Red Flags

Another common mistake is entering a secondary provider ID without verifying payer acceptance. Some billing software may default to populating this field with an old state number; this should be suppressed for Medicare claims. Audit red flags include:

• Inconsistent identifiers: If FL 56 (NPI) and FL 57 both contain numbers, auditors may question duplicate provider identification or mismatched data.
• Rejected claims: Although CMS ignores the data, some clearinghouses or secondary payers might misinterpret the entry and reject the claim.
• Ignoring payer-specific instructions: Using field 57 when a payer forbids it can lead to unnecessary rework. ^[3] reinforces the “not used” directive for Medicare.
• Leaving field blank but software inserts a dash or space: Some electronic formats require a blank or space; ensure the field is truly empty according to the billing format specifications.

To avoid these issues, configure billing systems to leave FL 57 blank for all payer types that follow CMS guidelines, and only enable the field when a specific payer contract mandates its use.

Related Codes/Fields

The table below lists UB-04 fields that interact with or are related to Box 57 (Other Provider IDs), particularly in the context of provider identification and payer information.

Field No.	Field Name	Relationship to FL 57
56	National Provider Identifier (NPI) – Billing Provider	The primary provider identifier; FL 57 is a secondary or alternate ID when used. [2]
50	Payer Name	Identifies the payer; if Medicare, FL 57 must be left blank. [3]
51	Health Plan Identification Number	May be used with FL 57 to cross-reference provider IDs in certain payer systems.
58	Insured’s Name	Required for all payer types; FL 57 is never used for patient identification. [2]
33	Billing Provider NPI (other location)	Not a direct field; FL 56 serves the same function for the billing provider.
76	Attending Provider Name and Identifiers	Contains NPI/ID for attending; FL 57 is for the billing entity only.
77	Operating Physician NPI	Another provider identifier field; FL 57 is separate and rarely used.
78	Other Physician ID	Similar “other” identifier field; both FL 57 and FL 78 are considered deprecated by CMS.

While FL 57 is largely obsolete for Medicare, any state or commercial payer that requires an “Other Provider ID” should clearly define the expected value. Until then, the field should remain empty to ensure compliance and avoid processing errors.

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References

[1] Maryland Medicaid — FL 57 — https://health.maryland.gov/mmcp/provider/Documents/ffs-billing/UB04-Hospital-Billing-Instructions%20%281%29.pdf

[2] CMS Chapter 25 — FL 57 — https://www.cms.gov/regulations-and-guidance/guidance/manuals/downloads/clm104c25.pdf

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