The FDA categorizes diagnostic tests by their complexity—from the least to the most complex: waived tests, moderate complexity tests, and high complexity tests.

CLIA categorization is determined after the FDA has cleared or approved a marketing submission, or upon request for legally marketed devices, as described in the FDA guidance Administrative Procedures for CLIA Categorization.  Tests that are waived by regulation under 42 CFR 493.15(c), or cleared or approved for home use, are categorized as waived.  Otherwise, the FDA determines the test’s complexity by reviewing the package insert test instructions, and using a criteria “scorecard” to categorize a test as moderate or high complexity (42 CFR 493.17). Each test is graded for level of complexity by assigning scores of 1, 2, or 3 for each of the seven criteria on the scorecard.

A score of 1 indicates the lowest level of complexity, and a score of 3 indicates the highest level. The scores for the 7 criteria are added together and tests with a score of 12 or less are categorized as moderate complexity, while those with a score above 12 are categorized as high complexity. The FDA will notify the sponsor of their CLIA categorization —usually within two weeks of the marketing clearance or approval.

Following categorization, a manufacturer of a test categorized as moderate complexity may request categorization of the test as waived through a CLIA Waiver by Application (CW) submission to the FDA.

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Categorization Criteria

1 - Knowledge

• Score 1. (A) Minimal scientific and technical knowledge is required to perform the test; and (B) Knowledge required to perform the test may be obtained through on-the-job instruction.
• Score 3. Specialized scientific and technical knowledge is essential to perform preanalytic, analytic or postanalytic phases of the testing.

2 - Training and experience

• Score 1. (A) Minimal training is required for preanalytic, analytic and postanalytic phases of the testing process; and (B) Limited experience is required to perform the test.
• Score 3. (A) Specialized training is essential to perform the preanalytic, analytic or postanalytic testing process; or Substantial experience may be necessary for analytic test performance.

3 - Reagents and materials preparation

• Score 1. (A) Reagents and materials are generally stable and reliable; and (B) Reagents and materials are prepackaged, or premeasured, or require no special handling, precautions or storage conditions.
• Score 3. (A) Reagents and materials may be labile and may require special handling to assure reliability; or (B) Reagents and materials preparation may include manual steps such as gravimetric or volumetric measurements.

4 - Characteristics of operational steps

• Score 1. Operational steps are either automatically executed (such as pipetting, temperature monitoring, or timing of steps), or are easily controlled.
• Score 3. Operational steps in the testing process require close monitoring or control, and may require special specimen preparation, precise temperature control or timing of procedural steps, accurate pipetting, or extensive calculations.

5 - Calibration, quality control, and proficiency testing materials

• Score 1. (A) Calibration materials are stable and readily available; (B) Quality control materials are stable and readily available; and (C) External proficiency testing materials, when available, are stable.
• Score 3. (A) Calibration materials, if available, may be labile; (B) Quality control materials may be labile, or not available; or (C) External proficiency testing materials, if available, may be labile.

6 - Test system troubleshooting and equipment maintenance

• Score 1. (A) Test system troubleshooting is automatic or self-correcting, or clearly described or requires minimal judgment; and (B) Equipment maintenance is provided by the manufacturer, is seldom needed, or can easily be performed.
• Score 3. (A) Troubleshooting is not automatic and requires decision-making and direct intervention to resolve most problems; or (B) Maintenance requires special knowledge, skills, and abilities.

7 - Interpretation and judgment

• Score 1. (A) Minimal interpretation and judgment are required to perform preanalytic, analytic and postanalytic processes; and (B) Resolution of problems requires limited independent interpretation and judgment.
• Score 3. (A) Extensive independent interpretation and judgment are required to perform the preanalytic, analytic or postanalytic processes; and (B) Resolution of problems requires extensive interpretation and judgment.

Note: A score of 2 will be assigned to a criteria heading when the characteristics for a particular test are intermediate between the descriptions listed for scores of 1 and 3.

In cases where a premarket submission is not needed but CLIA categorization is still appropriate (e.g., devices exempt from premarket notification), manufacturers may submit a request for CLIA categorization, which includes the package insert test instructions, to CDRH.