Gas chromatography mass spectrometry (GCMS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample.

GCMS is a highly sophisticated and precise analytical technique used to identify and quantify substances present in a test sample. GCMS offers several advantages in confirming drug test results, including Specificity: GCMS can distinguish between structurally similar compounds, reducing the risk of false positives.