Understanding the CLIA Number on UB-04 Form | Medical Billing

In the complex world of medical billing, healthcare professionals encounter numerous codes, forms, and acronyms. Among these is the CLIA number on the UB-04 form, a critical piece of information that plays a vital role in accurate billing and reimbursement processes. Whether you're a healthcare provider, biller, or patient, understanding the significance of the CLIA number is key to navigating the intricacies of the healthcare system effectively.

The CLIA Number: Unveiling Its Significance

Before we dive into the details, let's clarify the acronym: CLIA stands for Clinical Laboratory Improvement Amendments. The CLIA program, implemented by the Centers for Medicare and Medicaid Services (CMS)[[1]], regulates clinical laboratory testing to ensure quality and accuracy in diagnostic results. The CLIA number, associated with a laboratory's certification, signifies compliance with these regulations.

What is the UB-04 Form?

To understand the role of the CLIA number, it's essential to grasp the purpose of the UB-04 form. The UB-04 form, also known as the CMS-1450 form, is a standard document used by healthcare providers to submit medical claims for reimbursement[[1]]. This form contains crucial information about the services rendered to patients, including diagnostic tests performed in clinical laboratories.

The CLIA Number on UB-04 Form: Unlocking Its Purpose

The CLIA number's primary purpose on the UB-04 form is to indicate that the laboratory conducting the tests is CLIA-certified. By including the CLIA number, healthcare providers demonstrate compliance with federal regulations and ensure the accuracy and reliability of the diagnostic tests performed.

Locating the CLIA Number on the UB-04 Form

To identify the CLIA number on the UB-04 form, one must refer to the "FL45" field. FL45, also known as the "Service Provider Identification Number," is where the CLIA number is recorded. This field allows healthcare providers to input their unique CLIA number, enabling efficient tracking and verification of laboratory services.

Impact on Reimbursement: Why Does the CLIA Number Matter?

The presence of the CLIA number on the UB-04 form holds significant implications for reimbursement. Here's why it matters:

Ensures Compliance:

 By including the CLIA number, healthcare providers adhere to CMS regulations, ensuring that diagnostic tests are conducted in accredited laboratories. Compliance with CLIA requirements is vital for reimbursement, as it assures payers that the tests were performed in accordance with recognized quality standards.

Accurate Coding and Pricing: 

The CLIA number helps in proper coding and pricing of laboratory services. It allows payers to distinguish between CLIA-waived and non-waived tests, which have different coding and pricing structures. This differentiation helps prevent coding errors and ensures appropriate reimbursement for services rendered.

Facilitates Claims Processing: 

Including the CLIA number expedites claims processing and minimizes potential delays. The presence of the CLIA number provides payers with essential information regarding the laboratory where the tests were conducted, allowing for streamlined verification and reimbursement procedures.

FAQs: Clarifying Common Queries

To address common questions related to the CLIA number on the UB-04 form, here are some frequently asked questions:

Q: Is the CLIA number the same for all laboratories?

A: No, each laboratory has a unique CLIA number. The CLIA number is assigned to a laboratory when it applies for certification and is used to identify and track its testing activities.

Q: Can healthcare providers bill for laboratory services without a CLIA number?

A: No, healthcare providers must have a valid CLIA number to bill for laboratory services. The absence of a CLIA number may result in claim denials or delays in reimbursement.

Q: Where can healthcare providers obtain a CLIA number?

A: Healthcare providers can obtain a CLIA number by applying for certification through the CMS[[2]]. The CMS provides detailed instructions and guidance on the application process.

Q: Are there different types of CLIA certificates?

A: Yes, the CLIA program offers different types of certificates based on the complexity of tests performed. These include Certificate of Waiver, Certificate for Provider-Performed Microscopy Procedures, Certificate of Compliance, and Certificate of Accreditation[[2]].

Q: Is the CLIA number required for all laboratory tests?

A: No, certain laboratory tests are exempt from CLIA certification, known as CLIA-waived tests. These tests are simple and have a low risk of error, and healthcare providers can perform them without extensive laboratory infrastructure.


Understanding the CLIA number on UB-04 form is essential for healthcare providers, billers, and patients alike. By recognizing its purpose and locating it correctly, medical professionals can ensure compliance with regulations, accurate coding and pricing, and smooth reimbursement processes. The CLIA number acts as a crucial link between laboratory testing and proper medical billing, reinforcing the integrity and quality of diagnostic services.

So, next time you come across the CLIA number on a UB-04 form, remember its significance in unlocking accurate medical billing. Embrace the power of this small, but mighty, identifier and navigate the complexities of healthcare reimbursement with confidence!

For your reference, today's date is 2023-07-01

[1]: CMS website: Clinical Laboratory Improvement Amendments (CLIA)

[2]: Verywell Health: Preparing the UB-04 Form