UB04 Field 10: Patient Birthdate

Overview

Field 10 (Patient Birthdate) is a mandatory data element on the UB-04 (CMS-1450) claim form used to identify the patient and determine age-based coverage rules. It is located on the upper-left portion of the form, immediately following the patient's address. This field captures the patient's date of birth in an eight-digit numeric format: MMDDYYYY.

The National Uniform Billing Committee (NUBC) and CMS require this field to validate the patient’s identity against the payer's eligibility file. For Medicare and most commercial payers, this field is critical for calculating Medicare Secondary Payer (MSP) status and verifying that the patient is eligible for age-specific services, such as pediatric or geriatric-specific revenue codes CMS Pub. 100-04 Chapter 25.

When to Use This Field

Field 10 is required for every institutional claim, regardless of the Type of Bill (TOB). It must be populated for both inpatient and outpatient submissions to ensure the payer can match the claim to the correct member record.

Specific Billing Scenarios

• Newborn Billing: When billing for a newborn using the mother’s insurance ID, Field 10 must reflect the infant's actual date of birth, not the mother's. This is essential for the payer to create a unique member record for the infant SFHP UB-04 Instructions.
• Unknown Birthdate: In rare cases where a patient’s birthdate is completely unknown (e.g., unidentified trauma patients), CMS guidelines allow the use of zeros for all eight digits (00000000), though this often triggers a manual review or "Return to Provider" (RTP) status for further verification CMS Pub. 100-04 Chapter 25.

Step-by-Step Claim Example

A Skilled Nursing Facility (SNF) is billing for a 72-year-old patient admitted for post-surgical rehabilitation.

1. Patient Intake: The registrar verifies the patient's ID card and government-issued photo ID. The birthdate is confirmed as March 12, 1952.
2. Field 10 Entry: The biller enters 03121952 in Field 10. No slashes, dashes, or spaces are used.
3. Cross-Verification: The system checks Field 10 against Field 8: Patient Name and Field 60: Insured's Unique ID.
4. Submission: The claim is transmitted via the 837I electronic format.
5. Payer Response: The payer's adjudication system matches the birthdate to the member ID. Because the patient is over 65, the system automatically validates the use of Medicare Part A as the primary payer. If the birthdate had been entered as 03122022 (a typo), the claim would have been rejected immediately for an "Age/Procedure Conflict" because a 2-year-old cannot be eligible for standard Medicare retirement benefits.

Common Mistakes & Audit Red Flags

• Format Errors: Using a six-digit format (MMDDYY) instead of the required eight-digit format (MMDDYYYY). Modern EDI (Electronic Data Interchange) systems will typically scrub this, but paper claims with six digits are often rejected as "Incomplete Demographics" BCBSNC UB-04 Guide.
• Mismatched Data: Entering a birthdate that does not match the payer’s eligibility file. This is the #1 cause of "Member Not Found" denials. Even if the patient provides a different date at registration, the biller must use the date on file with the insurance company to ensure processing Best Medical Billing Denial Analysis.
• Newborn Date Logic: Entering the mother's birthdate in Field 10 while using a newborn-specific Revenue Code (e.g., 0170). This creates a "Logic Conflict" denial, as the system sees an adult patient receiving neonatal nursery services.

Related Codes & Fields

• Field 08: Patient Name
• Field 11: Patient Sex
• Field 12: Admission Date
• Field 60: Insured's Unique ID
• Revenue Code 0170: Nursery

References

1. CMS Pub. 100-04 Chapter 25
2. SFHP UB-04 Instructions
3. BCBSNC UB-04 Guide
4. Best Medical Billing Denial Analysis