Levels of standards are described as which set?

• A. Low, Midpoint, High
• B. Low, Mid, High, Very High
• C. Low, Mid, High, Ultra
• D. Low, Midpoint, Highest

Answer: (A)

In calibration and quality control, standards are described using three levels that span the assay’s range: low, midpoint, and high. The Low level tests the lower end and detection capability, the Midpoint sits within the typical clinical range to verify accuracy where results are usually reported, and the High level checks the upper end and helps assess linearity. This three-tier structure provides a practical way to evaluate performance across the full range, including sensitivity, accuracy, and linearity. Terms like Very High or Ultra aren’t standard descriptors for calibration levels in routine practice, and using a different middle-level term would don’t align with common practice.