UB-04 Field 12: Admission Date

Overview

Field 12, also known as Form Locator 12 (FL 12), captures the Admission Date or the date care was initiated for a patient. This field is located on the upper-left portion of the UB-04 claim form, directly below the patient's sex (Field 11). For inpatient facilities, this date represents the moment a physician formally writes the order to admit the patient to the facility. For outpatient or home health services, it signifies the Start of Care date.

The date must be entered in an eight-digit format (MMDDYYYY) or a six-digit format (MMDDYY) depending on specific payer requirements, though the National Uniform Billing Committee (NUBC) standardizes the eight-digit format for electronic 837I transactions. This field is critical for determining timely filing limits and validating the medical necessity of the stay relative to the physician's orders Medicare Claims Processing Manual Chapter 25.

When to Use This Field

Field 12 is mandatory for all inpatient claims, including acute care, psychiatric, and Skilled Nursing Facility (SNF) stays. It is also required for Home Health Agency (HHA) and Hospice claims to establish the start of an episode of care.

Specific Billing Scenarios

• Inpatient Hospitalization: A patient is admitted for surgery on 10/05/2024. Even if the claim only covers a portion of the stay (e.g., an interim bill), Field 12 must consistently reflect 10/05/2024.
• Home Health Start of Care: For a home health episode, Field 12 must match the date care was initiated, which should also align with the date submitted on the Request for Anticipated Payment (RAP) CMS Pub 100-04 Ch 25.
• Observation to Inpatient Conversion: If a patient is in observation for two days and then formally admitted, Field 12 must reflect the date the inpatient order was signed, not the date observation began Noridian Medicare Admission Date Guidelines.

Step-by-Step Claim Example

Patient Scenario: A 68-year-old Medicare beneficiary arrives at the Emergency Department on 11/12/2024. After 24 hours of observation, the attending physician signs an inpatient admission order at 10:00 AM on 11/13/2024. The patient is discharged on 11/16/2024.

Field Values:

• Field 6 (Statement Covers Period): 11122024 (From) – 11162024 (Through). Note that the "From" date includes the observation period due to the 3-day payment window rule.
• Field 12 (Admission Date): 11132024. This is the date the formal inpatient order was written.
• Field 13 (Admission Hour): 10 (representing 10:00 AM).
• Field 17 (Patient Status): 01 (Discharged to home).

Payer Response: The Medicare Administrative Contractor (MAC) validates that the Admission Date (11/13/2024) falls within the Statement Covers Period (11/12/2024–11/16/2024). Because the dates align with the physician's signed order in the medical record, the claim is processed for the DRG payment, including the bundled observation charges from 11/12/2024.

Common Mistakes & Audit Red Flags

• Mismatch with Physician Orders: The most frequent audit trigger is an Admission Date that precedes the signed and dated physician admission order. Auditors verify that the date in Field 12 matches the clinical documentation exactly Noridian Medicare Admission Date Guidelines.
• Confusing Field 12 with Field 6: Billers often mistakenly enter the same date in Field 12 and the "From" date of Field 6. While they may be the same, they serve different purposes; Field 6 represents the earliest service date on the bill (which may include pre-admission services), while Field 12 is the formal admission date MLN Matters SE1117.
• Incorrect Format: Using slashes (11/13/24) or dashes on a paper UB-04 can cause Optical Character Recognition (OCR) errors, leading to immediate rejections.

Related Codes & Fields

• Field 6: Statement Covers Period
• Field 13: Admission Hour
• Field 14: Priority (Type) of Admission or Visit
• Field 15: Point of Origin for Admission or Visit
• Field 17: Patient Discharge Status

References

1. Medicare Claims Processing Manual Chapter 25
2. Noridian Medicare Admission Date Guidelines
3. MLN Matters SE1117