How should an ND result be interpreted in a clearance decision?

• A. It is considered Not Detected and can support meeting clearance criteria
• B. It counts as a failure to meet criteria
• C. It requires immediate re-sampling
• D. It indicates data is missing and invalid

Answer: (D)

In clearance decisions, you must base the outcome on reliable, usable data. When a result comes back as ND, it means you don’t have a valid data point to rely on. Because the decision rests on meeting specific criteria, an ND result can’t be treated as a confirmation of meeting the criteria or as a straightforward failure. It leaves you with missing information, so the data are considered invalid for the decision as-is. That’s why the proper interpretation is that the ND indicates data is missing and invalid, and you need valid data (often by re-sampling or re-testing) before a clearance decision can be made.