How are MDL and LOQ treated in reporting results?

How are MDL and LOQ treated in reporting results?

• A. Results below MDL are final results; results between MDL and LOQ are exact.
• B. Results below MDL are non-detects or qualifiers; results between MDL and LOQ are approximate.
• C. Results above LOQ are always non-detects.
• D. LOQ is irrelevant for reporting.

Answer: (B)

The idea being tested is how detection and quantitation limits guide what you report for a measurement. The limit of detection (MDL) is the smallest concentration that can be reliably detected, while the limit of quantitation (LOQ) is the smallest concentration that can be quantified with acceptable precision and accuracy. In reporting, you don’t claim a definite measurement below the MDL. Instead, those results are treated as non-detects or flagged with a qualifier indicating they’re below the detection limit. If the result falls between MDL and LOQ, you’ve detected the analyte but you can’t quantify it with high confidence, so you report it as detected but approximate (estimated). Above LOQ, you can quantify with acceptable precision. This aligns with reporting practice where below MDL = non-detect or qualified, and between MDL and LOQ = detected but approximate.

The idea being tested is how detection and quantitation limits guide what you report for a measurement. The limit of detection (MDL) is the smallest concentration that can be reliably detected, while the limit of quantitation (LOQ) is the smallest concentration that can be quantified with acceptable precision and accuracy. In reporting, you don’t claim a definite measurement below the MDL. Instead, those results are treated as non-detects or flagged with a qualifier indicating they’re below the detection limit. If the result falls between MDL and LOQ, you’ve detected the analyte but you can’t quantify it with high confidence, so you report it as detected but approximate (estimated). Above LOQ, you can quantify with acceptable precision. This aligns with reporting practice where below MDL = non-detect or qualified, and between MDL and LOQ = detected but approximate.