Glossary

Confirmation cutoff

The concentration above which the mass-spectrometry confirmation reports a verified positive.

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Confirmation cutoffs are set lower than screening cutoffs because mass spectrometry is highly specific. They define the threshold at which a verified positive is reported.

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Glossary

Cutoff level

The concentration threshold at or above which a sample is reported as non-negative.

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GC-MS (gas chromatography–mass spectrometry)

A confirmation method that separates and identifies individual analytes by mass-to-charge ratio.

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LC-MS/MS (liquid chromatography–tandem mass spectrometry)

A confirmation method that uses two stages of mass analysis, often used for fentanyl and other low-cutoff analytes.