Overview
The UB-04 claim form utilizes Form Locator (FL) 13 to identify the specific hour a patient was admitted for care [1]. Code 03 is a specific temporal indicator used to signify that the patient's admission occurred during the early morning window of 03:00 AM to 03:59 AM [1]. This field is a critical component of the admission data set, which also includes the date of admission and the priority of the visit [1]. The use of a two-digit coding structure, ranging from 00 to 23, allows for precise tracking of hospital resources and patient intake patterns across a 24-hour cycle [1].
For inpatient facilities, this code helps establish the start of the clinical episode and the first day of billing [1]. While the code is mandatory for most inpatient claims, its application varies depending on the specific facility type and the nature of the services provided [1]. Nursing facilities, for instance, are instructed to enter admission data only for the initial month of billing to establish the start of care [1]. By using Code 03, providers accurately report that a patient was processed into the system during the third hour after midnight [1].
When to Use
Code 03 must be used in Form Locator 13 whenever a patient is admitted for inpatient or outpatient care between 03:00 AM and 03:59 AM [1]. This requirement is mandatory for all inpatient claims, with the specific exception of bill type 21x, which represents intermediate care facilities [1]. For outpatient billing, the inclusion of the admission hour is considered optional, though it may still be provided to maintain comprehensive records of the patient encounter [1].
In the context of nursing facilities, the admission hour and date are required specifically for the first month of billing to document the initiation of services [1]. When a patient arrives at the facility and completes the admission process during the 03:00 AM hour, the provider must enter "03" in FL 13 to comply with hospital billing instructions [1]. This code is part of a larger data set that includes the Priority (Type) of Visit in FL 14, which is required for inpatient billing to indicate the urgency of the admission, such as an Emergency (Code 1) [1].
Step-by-Step Claim Example
To properly document an admission occurring at 03:15 AM on a UB-04 claim form, the billing department must follow these steps based on Maryland Medicaid instructions:
- Identify the Admission Time: Confirm through the medical record that the patient was admitted for inpatient or outpatient care during the 03:00 AM to 03:59 AM window [1].
- Locate Form Locator 13: Find the field labeled "Admission Hour" on the UB-04 claim form [1].
- Enter the Code: Input the two-digit code "03" into FL 13 [1].
- Verify Bill Type: Ensure the claim is not for bill type 21x (intermediate care), as the admission hour is not required for that specific classification [1].
- Coordinate with FL 14: For inpatient claims, proceed to Form Locator 14 to enter the Priority (Type) of Visit [1]. If the patient required immediate medical intervention, enter Code 1 for "Emergency" [1].
- Nursing Facility Exception: If the provider is a nursing facility, ensure this data is being entered for the first month of billing only [1].
- Final Review: Double-check that the code "03" corresponds to the 03:00-03:59 AM timeframe and not the 03:00 PM (15:00) timeframe, which would require Code 15 [1].
Common Mistakes & Audit Red Flags
A frequent error in hospital billing is the confusion between the AM and PM coding structures [1]. Using Code 03 when the patient was actually admitted at 3:00 PM (which requires Code 15) can lead to data inconsistencies and potential claim denials [1]. Auditors look for these discrepancies by comparing the admission hour in FL 13 with the clinical notes and the priority of visit code in FL 14 [1]. For example, an "Emergency" priority (Code 1) should logically align with the documented admission time [1].
Another common mistake is failing to include the admission hour on inpatient claims where it is mandatory [1]. Except for bill type 21x, all inpatient claims must have this field populated [1]. Conversely, nursing facilities may trigger an audit flag if they continue to report the admission hour and date beyond the first month of billing, as it is only required for the initial billing cycle [1]. Finally, providers must ensure they do not use Code 03 for admissions occurring at 12:00 Midnight (Code 00) or 12:00 Noon (Code 12), as these specific times have their own designated codes within the 00-23 structure [1].
Related Codes/Fields
| Field / Code | Name | Description |
|---|---|---|
| FL 13 / Code 15 | 03:00 PM - 03:59 PM | The code used for admissions occurring in the 3:00 hour of the afternoon [1]. |
| FL 13 / Code 00 | 12:00 AM - 12:59 AM | The code used for admissions occurring during the midnight hour [1]. |
| FL 14 / Code 1 | Emergency | Priority code indicating the patient requires immediate medical intervention [1]. |
| Bill Type 21x | Intermediate Care | The specific bill type for which the Admission Hour (FL 13) is not required [1]. |
| FL 13 / Code 12 | 12:00 PM - 12:59 PM | The code used for admissions occurring during the noon hour [Maryland Medicaid — FL 13 (Code 03)]. |
References
[1] Maryland Medicaid — FL 13 (Code 03) — https://health.maryland.gov/mmcp/provider/Documents/ffs-billing/UB04-Hospital-Billing-Instructions%20%281%29.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: 2026-05-29
Sources: CMS Pub. 100-04 Chapter 25, NUBC Official UB-04 Manual, Medicare Contractor Bulletins (Noridian, Palmetto, CGS)