UB04 Field 75: Future Use

Overview

Field 75 on the UB‑04 claim form is designated as “Reserved for Assignment by the NUBC” and is not currently in use. According to Maryland Medicaid, the field is explicitly listed as “FL 75 Reserved for Assignment by NUBC” in its UB‑04 hospital billing instructions, meaning no data should be reported in this field ^[1]. The Centers for Medicare & Medicaid Services (CMS) reinforce this in both the Medicare Claims Processing Manual, Chapter 25, and Transmittal R1915CP, stating that “FL 75 – Reserved Not used. Data entered will be ignored” ^[2]; ^[3]. Because the field is reserved for future assignment by the National Uniform Billing Committee (NUBC), it currently has no defined purpose on either inpatient or outpatient claims. Providers must ensure that Field 75 is left blank on all UB‑04 submissions to avoid sending data that will be disregarded by payers and clearinghouses.

When to Use

Field 75 is never used under current billing requirements. The Maryland Medicaid instructions confirm that the field is “reserved” and does not correspond to any active data element ^[1]. CMS guidance is even more explicit: “FL 75 – Reserved Not used. Data entered will be ignored” ^[2]. This means that even if a provider accidentally places information in Box 75, the payer’s processing system will strip it out or ignore it. There are no situational requirements, no conditional use cases, and no future date when the field will become active – any change would require an NUBC update. Therefore, the correct action is to always leave Field 75 blank. The field applies equally to inpatient and outpatient claims; as noted by CMS, it is “not used on outpatient claims” and by extension the same logic applies to inpatient bills ^[2]. In the rare event that a billing system automatically populates legacy data, the provider must edit the claim to remove any content from this field before submission.

Step-by-Step Claim Example

To illustrate correct handling of Field 75, consider a hospital submitting a UB‑04 for an inpatient stay (e.g., a two‑day admission for pneumonia). The biller completes all required fields: FL 1–6 (provider info, patient name, dates of service), FL 8–20 (patient identifiers, insurance data), FL 36–42 (revenue codes and charges), FL 50–66 (payer information, diagnosis codes), and so on. When the biller reaches Box 75, they must leave the field entirely blank – no digits, no spaces, no zeros, and no placeholders. The corresponding electronic 837 institutional transaction does not expect any value in the data element associated with this field. After completing the remaining fields (FL 76 – Attending Provider, FL 80 – Remarks, etc.), the claim is ready for submission. A typical paper UB‑04 would show an empty rectangle in the row of Boxes 71–75. In the electronic equivalent, the segment that would normally contain the “Future Use” indicator is omitted entirely. Following this practice ensures that the claim is processed without the risk of data being ignored or triggering a rejection for invalid content. Remember: because CMS rule states “Data entered will be ignored,” any populated value will simply be discarded, but it is best practice not to enter anything at all ^[3]; ^[2].

Common Mistakes & Audit Red Flags

The most common mistake is entering data in Field 75 – whether a legacy code, a zero, or a filler character. While CMS states that such data “will be ignored,” the presence of unexpected characters can cause clearinghouse edits or payer rejections in certain systems that haven’t fully suppressed the field ^[2]. An audit red flag arises when a claim shows anything in Box 75, because auditors interpret it as a sign that the biller is not following NUBC guidelines. Additionally, if a provider mistakenly treats Field 75 as an “other” diagnosis or procedure field, that could lead to missing information in the correct fields (FL 67, FL 74), potentially causing denials for incomplete coding. Another error is copying data from a previous era when UB‑04 fields may have been repurposed; any such data should be removed. To avoid flags, always verify that Box 75 is blank before submission. If a clearinghouse rejects a claim citing “invalid data in reserved field,” the solution is to delete whatever was entered. Providers should also train billing staff that Field 75 is not a “notes” or “miscellaneous” field. Finally, remember that the NUBC may someday assign a meaning to this field; until then, “not used” is the official stance from both CMS and Maryland Medicaid ^[1]; ^[3].

Related Codes/Fields

The following table lists other UB‑04 fields that are also designated as “Reserved for Assignment by NUBC” or share a similar “not used” status.

Field Number	Field Name / Description	Source
FL 68	Reserved for Assignment by NUBC	[1]
FL 73	Reserved for Assignment by NUBC	[1]
FL 75	Reserved for Assignment by NUBC (this field) – Data entered will be ignored	[2]; [3]
FL 79	Other Physician ID – appears reserved in some payer guides (but CMS uses it as situational)	[1] – note FL 79 is listed but not marked “reserved” in Maryland; however, for completeness, it is often treated as optional.
FL 80	Remarks – not reserved but can be used for special notes; data in FL 75 should not be confused with remarks.	UB‑04 standard (general knowledge, but not used per sources for this topic)

Note: Only fields explicitly stated as “Reserved for Assignment by NUBC” in the Maryland Medicaid source are FL 68, FL 73, and FL 75. Providers should always verify current UB‑04 guidelines from the NUBC and their specific payer.

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References

[1] Maryland Medicaid — FL 75 — https://health.maryland.gov/mmcp/provider/Documents/ffs-billing/UB04-Hospital-Billing-Instructions%20%281%29.pdf

[2] CMS Chapter 25 — FL 75 — 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