CurrentMedicarePolicy N/A

Laboratory Developed Tests (LDTs) — CLIA Analytical Validation and Coverage Criteria

Explains CMS/CLIA authority over LDTs, contrasts it with FDA authority, and summarizes CLIA analytical validation and laboratory requirements for LDTs; intended for laboratories, clinicians ordering tests, and policy reviewers.

Policy Summary

PayerMedicare

PolicyLaboratory Developed Tests (LDTs) — CLIA Analytical Validation and Coverage Criteria

Policy CodePolicy N/A

Change TypeNo material change

Effective DateN/A

Next Review DateN/A

Key ActionDo not release LDT results until the laboratory documents required analytical validation (accuracy, precision, sensitivity, specificity, reportable range, reference interval) per CLIA.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

biennialValidation review frequency

high complexityTest complexity

analytical validity elementsAnalytical elements

Coverage Criteria for Laboratory-Developed Tests (LDTs)

CLIA-based coverage criteria for LDT use

Covered when laboratory meets CLIA high-complexity requirements and completes required analytical validation:

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CLIA requirements for LDTs: Laboratory must be certified under CLIA and meet all applicable requirements for high complexity testing.high complexity

LDTs are considered high complexity tests and must meet corresponding CLIA requirements.

Analytical validation prior to result release: Laboratory may not release LDT results until it has established performance characteristics (accuracy, precision, analytical sensitivity, analytical specificity, reportable range, reference interval, and any other required characteristics) for use in its specific environment per 42 CFR 493.1253(b)(2).N/A

Validation is laboratory-specific to the conditions, staff, equipment, and patient population and is performed by the laboratory intending to use the test on patient specimens.

Documentation and survey review: Analytical validation must be documented and is subject to review during routine biennial CLIA survey; CLIA does not assess clinical validity.biennial

Routine CLIA survey reviews laboratory-specific analytical validation after testing has begun; clinical validity is not reviewed under CLIA.

CLIA regulates laboratory operations and test performance but does not assess clinical validity. The absence of FDA premarket review for a Laboratory Developed Test (LDT) means its clinical validity may not have been evaluated by the FDA; CMS/CLIA and FDA have different, complementary authorities with CLIA focused on laboratory analytic performance and FDA focused on clinical validity under premarket review.

Use of LDTs within the developing laboratory after analytical validation

Use of LDTs within the developing laboratory is covered after completion of the laboratory-specific analytical validation:

Laboratory-specific validation: Analytical validation must be performed by the laboratory intending to use the test on patient specimens and must reflect the laboratory's specific conditions, staff, equipment, and patient population.N/A

Findings from this validation are not meaningful outside of the validating laboratory.

Required performance characteristics: Validation must evaluate accuracy, precision, analytical sensitivity, analytical specificity, reportable range, reference interval, and any other performance characteristics required for the test system in that laboratory.N/A

These elements comprise the analytical validity assessment under CLIA.

Operational restriction before validation: The laboratory must not release LDT results until the required analytical performance characteristics have been established and documented.N/A

Documentation of validation is subject to review during the routine CLIA survey.

Provider Actions, Documentation, and Operational Requirements

Note

Prior authorization

CLIA does not require prior authorization. FDA premarket review is a separate authority and is not required by CLIA for LDTs.

Note

Documentation Required

Required analytical validation documentation

Laboratories must document analytical validation for any LDT they intend to use. Documentation must address accuracy, precision, analytical sensitivity, analytical specificity, reportable range, reference interval, and any other performance characteristics required for the specific test system in the laboratory's environment.

Denial Risk

Prohibition on releasing LDT results before analytical validation

Release of LDT results is prohibited until the laboratory has established the required analytical performance characteristics per 42 CFR 493.1253; validation must be performed by the laboratory intending to use the test and is specific to that laboratory's conditions, staff, equipment, and patient population.

Do not report patient results before completing CLIA-required analytical validation (42 CFR 493.1253(b)(2)).
Validation is laboratory-specific and will be reviewed during the laboratory's biennial CLIA survey.

Ordering Requirements and Clinician Restrictions

Billing Rule

Ordering requirements — laboratory must meet CLIA high-complexity standards

There are no clinician-specific ordering restrictions stated; however, laboratories must be CLIA-certified and meet all applicable requirements for high-complexity testing to perform LDTs.

Ensure the performing laboratory holds CLIA certification for high-complexity testing.
Ordering clinicians should confirm the laboratory completed required analytical validation before relying on results.

Definitions

inv-08: Laboratory Developed Test (LDT)

DefinitionAn in vitro diagnostic test manufactured by and used within a single laboratory (a laboratory with a single CLIA certificate).

Also known asIn‑house developed tests or 'home brew' tests.

Scope of useDesigned, manufactured, and used within the same laboratory (not distributed for use by other laboratories).

inv-09: Clinical validity

DefinitionClinical validity is the accuracy with which a test identifies, measures, or predicts the presence or absence of a clinical condition or predisposition in a patient.

CLIA scopeCLIA does not address clinical validity; it focuses on analytical validity and laboratory processes.

FDA roleFDA's premarket clearance and approval processes assess clinical validity as part of evaluating safety and effectiveness.

Background

A Laboratory Developed Test (LDT) is an in vitro diagnostic test created and used within a single laboratory. CLIA’s oversight centers on analytical validity — ensuring tests produce accurate and reliable results in the laboratory’s specific environment — including the documentation and demonstration of appropriate performance characteristics. CLIA does not perform FDA-style premarket review of clinical validity; that assessment falls under FDA authority.

Not Covered / Limitations

Because CLIA does not address clinical validity, results from LDTs that have not undergone FDA premarket review may lack an independent FDA assessment of whether the test accurately identifies, measures, or predicts a clinical condition. This policy therefore highlights that clinical validity is not guaranteed by CLIA and may be unassessed absent FDA review.