Overview
Form Locator (FL) 68 on the UB-04 claim form is a reserved field designated for assignment by the National Uniform Billing Committee (NUBC). Currently, this field is not used for any standard billing purpose across Medicare, Medicaid, or commercial payers. The Maryland Medicaid UB-04 Hospital Billing Instructions explicitly list FL 68 as "Reserved for Assignment by NUBC" in their table of contents, and the CMS Chapter 25 manual states "FL 68 – Reserved Not used. Data entered will be ignored." [1], [2]
The CMS R1915CP transmittal further reinforces this requirement with the direct statement: "FL 68 - Reserved Not used." [3] Any data entered into FL 68 will be ignored by Medicare processing systems. This means providers should leave this field blank on all UB-04 claim submissions, whether for inpatient or outpatient services.
Despite its non-functional status, FL 68 maintains its place on the form structure between FL 67 (Other Diagnosis Codes) and FL 69 (Admitting Diagnosis). It serves as a placeholder should the NUBC assign it a specific use in future billing updates.
When to Use
Never. Field 68 is a reserved field with no current billing application. Under no circumstances should providers enter diagnosis codes, procedure codes, or any other data into this field. The CMS instructs that "Data entered will be ignored," meaning any information placed here has no effect on claim processing—it is simply discarded. [2]
For both inpatient and outpatient claims, FL 68 must remain empty. If your billing software auto-populates this field or if you are manually completing a UB-04 hardcopy, verify that FL 68 is blank before submission. For Maryland Medicaid specifically, the field is listed as "Reserved for Assignment by NUBC," echoing the same requirement across all payer types. [1]
All diagnosis information (principal diagnosis, admitting diagnosis, external cause codes, and other diagnosis codes) should be submitted in the proper fields: FL 67 (Principal Diagnosis), FL 67 A-Q (Other Diagnosis Codes), FL 69 (Admitting Diagnosis), and FL 72 (External Cause of Injury Code). Do not use FL 68 as a substitute for any of these fields.
Step-by-Step Claim Example
Scenario: A 72-year-old patient is admitted for congestive heart failure exacerbation with secondary diagnoses of hypertension and type 2 diabetes. You are preparing the UB-04 inpatient claim.
Locate Box 68 on the UB-04 claim form. It is positioned between Box 67 (Diagnosis Codes) and Box 69 (Admitting Diagnosis).
Verify field is empty. Check your billing software to ensure no data has been accidentally inserted. If using a paper form, leave the box completely blank—do not write "N/A," "0," or any other characters.
Enter correct diagnosis codes in proper fields:
- FL 67: I11.0 (Principal Diagnosis Code)
- FL 67 A-Q: I10 (Other Diagnosis Code - Hypertension)
- FL 67 A-Q: E11.9 (Other Diagnosis Code - Type 2 Diabetes)
- FL 69: I50.9 (Admitting Diagnosis - Heart Failure)
Submit the claim. The payer will process the diagnosis codes from the appropriate fields and ignore any content in FL 68.
Post-submission audit. After claim acceptance, review the remittance advice to confirm there are no rejections related to FL 68. If a rejection does occur, it typically indicates your billing software incorrectly populated this field, requiring a software correction and claim resubmission.
Common Mistakes & Audit Red Flags
Mistake 1: Entering diagnosis codes in FL 68. Some billers mistakenly use FL 68 as an overflow field for additional diagnosis codes when FL 67 A-Q runs out of space. This is incorrect. If you need more diagnosis codes than FL 67 A-Q can accommodate, they should be submitted on a separate claim or via electronic submission that supports additional diagnosis fields—never in FL 68.
Mistake 2: Using FL 68 for internal reference numbers. Providers occasionally place proprietary tracking numbers or internal codes in reserved fields. This practice can trigger payer edits that reject the claim or flag it for manual review. Always use FL 80 (Remarks) for any necessary narrative information.
Mistake 3: Assuming payers treat it like a notes field. Because some state Medicaid programs (like Maryland) list FL 68 as "Reserved for Assignment by NUBC," inexperienced billers might interpret this as "available for special purposes." [1] It is not. Reserved means unused until the NUBC formally assigns a purpose.
Audit Red Flags:
- Claim rejections or electronic remittance advice errors referencing invalid field content
- Payer inquiries about "extra data" found in the claim transmission
- Cost report audits that question why diagnosis counts don't match submitted data
Related Codes/Fields
| Field Number | Field Name | Usage | Relationship to FL 68 |
|---|---|---|---|
| FL 67 | Principal Diagnosis Code | Required - Primary diagnosis for the encounter | Primary diagnosis field; FL 68 is not a substitute |
| FL 67 A-Q | Other Diagnosis Codes | Conditional - Secondary diagnoses (up to 17) | Contains the diagnosis data some mistakenly put in FL 68 |
| FL 69 | Admitting Diagnosis | Required for inpatient - Condition at admission | Documented in field immediately after FL 68 |
| FL 70A-C | Patient's Reason for Visit | Outpatient - Chief complaint or symptom | Captures outpatient presenting issue |
| FL 72A-C | External Cause of Injury Code | Conditional - E-codes for injuries | Separate field for injury causation |
| FL 66 | Diagnosis Code Qualifier | Required - ICD version indicator | Identifies code set version (e.g., ICD-10) |
| FL 73 | Reserved for Assignment by NUBC | Not used | Another reserved field; same rules apply |
Note: All fields listed are active and functional. FL 68 and FL 73 are currently the only form locators designated as "Reserved for Assignment by NUBC" that have no billing purpose. When NUBC assigns a function to these fields in future form revisions, CMS and state Medicaid agencies will issue updated billing instructions to define proper usage. [3]
References
[1] Maryland Medicaid — FL 68 — https://health.maryland.gov/mmcp/provider/Documents/ffs-billing/UB04-Hospital-Billing-Instructions%20%281%29.pdf
[2] CMS Chapter 25 — FL 68 — 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
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Start ExtractingThis guide was developed using official CMS and NUBC guidelines, combined with patterns observed from processing thousands of real UB-04 documents through our system.
Last Updated: 2026-06-03
Sources: CMS Pub. 100-04 Chapter 25, NUBC Official UB-04 Manual, Medicare Contractor Bulletins (Noridian, Palmetto, CGS)