What Is a CLIA Number in Medical Billing?

A CLIA number is a fundamental component of compliant medical billing for laboratory services. It serves as a unique identifier, signaling that a laboratory meets federal quality standards. Understanding its purpose and proper application is important for healthcare providers and billing professionals to ensure accurate claim submission and appropriate reimbursement.

Defining the CLIA Number

The Clinical Laboratory Improvement Amendments (CLIA) of 1988 established federal regulations for all laboratory testing performed on human specimens in the United States. A CLIA number is a unique identifier issued by the Centers for Medicare & Medicaid Services (CMS) to laboratories that adhere to these standards, ensuring the accuracy, reliability, and timeliness of patient test results.

The primary purpose of the CLIA number is to safeguard public health by ensuring the quality of laboratory testing. It is assigned to a specific laboratory location and is tied to a particular CLIA certificate type. These certificate types, such as Certificate of Waiver, Certificate for Provider-Performed Microscopy Procedures, Certificate of Compliance, or Certificate of Accreditation, indicate the complexity of tests the laboratory is authorized to perform.

When a CLIA Number is Necessary

A CLIA number is required for medical billing whenever an entity performs laboratory tests on human specimens for reimbursement. This applies to claims sent to Medicare, Medicaid, and most private insurers. Any organization or individual conducting clinical laboratory testing on humans, regardless of its setting, must possess a valid CLIA certificate and its corresponding number.

Facilities requiring a CLIA number include independent laboratories, hospital laboratories, physician office laboratories, and clinics. The specific type of laboratory test dictates the necessary CLIA certificate, which in turn means a CLIA number is a prerequisite for billing those tests. Common examples of tests that require a CLIA number range from routine blood and urine analyses to more complex pathology and microbiology tests.

Even simple, Food and Drug Administration (FDA)-approved waived tests necessitate a Certificate of Waiver and a CLIA number for billing. Without the appropriate CLIA certification, claims may be denied. Obtaining and maintaining the correct CLIA certificate ensures compliance and facilitates proper reimbursement for laboratory services.

Using the CLIA Number in Billing Claims

The CLIA number plays a direct role in the claims submission process, appearing on standard claim forms to facilitate reimbursement for laboratory services. On the CMS-1500 form, used for professional claims, the CLIA number is typically entered in Box 23. For institutional claims submitted on the UB-04 form, the CLIA number is reported in Form Locator 81.

Correct inclusion of the CLIA number validates that the performing laboratory is authorized and compliant with federal regulations for the tests being billed. Payers use this number to verify the laboratory’s certification status and confirm the types of tests it is approved to perform. This verification helps prevent claim denials and ensures timely payment.

Failure to include a valid or correct CLIA number on a claim can result in processing issues. Claims may be rejected or denied, leading to payment delays and increased administrative burden. Medicare contractors and many commercial payers cross-check CLIA numbers against their registries, and automated systems may reject claims that lack a valid or appropriately matched CLIA number.