What is field verification?

• A. Verification performed inside the lab only.
• B. It requires only software checks.
• C. Verification performed outside the lab, on site, using portable standards.
• D. It is identical to calibration.

Answer: (C)

Field verification is the on-site check of an instrument’s measurement performance using portable reference standards to confirm it still meets its specified accuracy in real field conditions. This on-site verification, done outside the lab with portable standards, ensures the instrument operates correctly when used where measurements are actually taken, not just in a controlled setting. It differs from calibration, which is a thorough adjustment typically performed in a lab to establish the instrument’s true response.

Choices that describe lab-only work or focus only on software checks miss the essential on-site, physical verification against portable standards. Field verification isn’t identical to calibration because its goal is to confirm the instrument remains within tolerance during normal field use, rather than to derive a new calibration.