UB04 Admission Hour Code 09: 09:00 AM - 09:59 AM

Overview

Admission Hour Code 09 represents the one‑hour window from 09:00 AM to 09:59 AM on the UB‑04 claim form. This code is entered in Field Locator (FL) 13 – Admission/Start of Care Date, which is required on inpatient bills and may also be used for outpatient care start dates. ^[1] specifies that the admission hour must be reported using military time (00–23), where 00 = 12:00 AM (midnight), 01 = 1:00 AM, and so on up to 23 = 11:00 PM. Code 09 therefore corresponds to the hour beginning at 9:00 AM. The UB‑04 form itself is a standardized institutional claim form used by hospitals, skilled nursing facilities, and other providers; the MassHealth UB‑04 Billing Guide provides general instructions for completing the form, including the use of code sets for fields such as FL 13. ^[2] While the MassHealth guide does not list individual hour codes, it confirms that the UB‑04 is the accepted paper claim format for MassHealth (though electronic submission is now required unless an exemption is granted). Accurate reporting of the admission hour is essential for proper claim processing, length‑of‑stay calculations, and compliance with payer audit requirements.

When to Use

Code 09 must be used when a patient is admitted for inpatient care or when outpatient care begins during the clock hour from 09:00 AM up to (but not including) 10:00 AM. ^[1] states that FL 13 is required on inpatient bills only, but the same field can be used to record the start of outpatient care. The hour code is a two‑digit number (00–23) that represents the hour of admission in military time. For example, if a patient is admitted at 9:15 AM, the correct code is 09; if admitted at 9:59 AM, code 09 still applies. The code does not capture minutes—only the hour. Providers should use the actual time of admission as documented in the medical record. ^[2] emphasizes that all fields on the UB‑04 must be completed accurately to prevent claim rejections or delays. Therefore, code 09 should be selected only when the admission time is between 09:00 and 09:59.

Step‑by‑Step Claim Example

Consider a patient admitted to a general hospital on January 15, 2024, at 9:30 AM. The provider is completing a paper UB‑04 claim for inpatient services.

1. Locate Field 13 on the UB‑04 form. This field is divided into two parts: the date (MM/DD/YY) and the two‑digit hour code.
2. Enter the admission date: 01/15/24.
3. Enter the admission hour code: 09. Because the admission occurred at 9:30 AM (within the 09:00–09:59 window), code 09 is correct. ^[1] confirms that the hour code must be in military time; 09 represents 9:00 AM.
4. Complete remaining required fields (e.g., patient name, provider number, diagnosis codes) according to the payer’s instructions. The MassHealth UB‑04 Billing Guide provides detailed instructions for each field. ^[2]
5. Submit the claim electronically (as required by MassHealth unless an exemption is granted) or on paper if approved. The admission hour code will be used by the payer to verify length of stay, determine DRG assignment, and calculate payment.

If the same patient were admitted at 9:59 AM, code 09 would still be used. If admitted at 10:00 AM exactly, code 10 would apply. This precision ensures that the claim reflects the correct hour of admission.

Common Mistakes & Audit Red Flags

• Using code 09 for 9:00 PM (21:00): A frequent error is confusing AM and PM. Code 09 is only for 9:00–9:59 AM; 9:00 PM is code 21. ^[1] explicitly defines military time, so providers must convert standard time correctly.
• Omitting the hour code entirely: Some billers leave the hour portion of FL 13 blank. This can cause the claim to be rejected or returned for correction. The field requires both date and hour.
• Using a non‑numeric or invalid code: Entering “09” as “9” (without leading zero) or using letters is not acceptable. The code must be exactly two digits.
• Inconsistent documentation: If the medical record shows admission at 9:20 AM but the claim uses code 10, auditors may flag a discrepancy. Always match the hour code to the documented time.
• Applying code 09 to outpatient visits incorrectly: While FL 13 can be used for outpatient start of care, some payers require a different field (e.g., FL 45 for outpatient services). Check payer-specific instructions. ^[2] notes that providers must follow the payer’s billing guide for each field.
• Ignoring payer edits: MassHealth and Medicare may edit claims where the admission hour is inconsistent with the date or type of service. For example, an admission hour of 09 on a weekend might trigger a review if the facility typically admits only emergencies. Accurate coding reduces audit risk.

Related Codes/Fields

Code	Meaning (Military Time)	Field
00	12:00 AM – 12:59 AM	FL 13
01	1:00 AM – 1:59 AM	FL 13
08	8:00 AM – 8:59 AM	FL 13
09	9:00 AM – 9:59 AM	FL 13
10	10:00 AM – 10:59 AM	FL 13
21	9:00 PM – 9:59 PM	FL 13
23	11:00 PM – 11:59 PM	FL 13

All codes are defined in ^[1]. Field 13 is the only field on the UB‑04 that captures the admission hour; no other field uses these hour codes. Providers should also be aware of FL 12 (Admission Type) and FL 14 (Admission Diagnosis), which are related but do not use hour codes. The MassHealth UB‑04 Billing Guide provides a complete list of code sets for all fields. ^[2] Accurate use of code 09 ensures that the admission hour is correctly communicated to the payer, supporting proper reimbursement and audit compliance.

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References

[1] CMS R1915CP — https://www.cms.gov/Regulations-and-Guidance/Guidance/Transmittals/downloads/R1915CP.pdf

[2] MassHealth UB-04 Guide — https://www.mass.gov/doc/ub-04-billing-guide-0/download