Gamma-hydroxybutyrate (GHB) is a prescribed medication as well as a drug of abuse. Its detection in various matrices for in-field forensic scientists remains a challenge. In the current study, AKR7A2 was purified using Ni-affinity chromatography. The Michaelis-Menten constant for the GHB oxidation reaction was 10 mM, and the minimum detection limit was 4 mM. Ethanol was not a substrate for AKR7A2. In a coupled reaction with NADP(+), phenazine methosulfate (PMS), and 2,6-dichlorophenolindophenol, various beverages (orange juice, milk, soda, and numerous alcoholic drinks) containing GHB turned from blue to light yellow. In a second coupled reaction where diaphorase replaced PMS, the presence of GHB also caused the expected change of color in various beers. (Published Abstract)