XRF positive classification

XRF positive classification

• A. Indicates lead is present on the testing combination at or above 1.0 mg/cm2.
• B. Indicates the sample is inconclusive.
• C. Indicates lead is absent from testing combination.
• D. Indicates XRF instrument malfunction.

Answer: (A)

A positive XRF classification means lead is present on the tested surface at or above the action level of 1.0 mg/cm2. XRF readings quantify lead mass per unit area, so when the result reaches or exceeds 1.0 mg/cm2, it indicates a significant lead presence that requires attention or action per standard guidelines. This interpretation is the best fit because it directly ties the positive label to lead being present at or above the defined threshold. Readings below that threshold would be considered negative or inconclusive depending on the instrument’s detection limits and sampling conditions, and a malfunction would show up as a device or readout error rather than a clean positive result.

A positive XRF classification means lead is present on the tested surface at or above the action level of 1.0 mg/cm2. XRF readings quantify lead mass per unit area, so when the result reaches or exceeds 1.0 mg/cm2, it indicates a significant lead presence that requires attention or action per standard guidelines. This interpretation is the best fit because it directly ties the positive label to lead being present at or above the defined threshold. Readings below that threshold would be considered negative or inconclusive depending on the instrument’s detection limits and sampling conditions, and a malfunction would show up as a device or readout error rather than a clean positive result.