Under CLIA QC requirements, how many levels of control materials should be used each day?

• A. At least 1 level daily
• B. None required
• C. At least 2 levels daily
• D. At least 3 levels daily

Answer: (C)

The main idea here is how many control material levels are used to monitor test performance each day under CLIA. Quality control requires using control materials to verify that a test method is performing correctly, and the typical requirement is to run at least two levels of control materials daily. Using two levels ensures you’re checking the assay across its measuring range and can detect both bias and drift that a single level might miss. If you used only one level, you could miss problems that appear at other concentrations. Using three levels is not the standard requirement for everyday QC, though some methods or facilities might implement more rigorous checks. Therefore, two levels daily best satisfies CLIA QC expectations while balancing practicality.