The formation of a green or green-blue colour after a few minutes is positive.
Lieberman–Burchard is a reagent used in a colourimetric test to detect cholesterol, which gives a deep green colour.
The colour is due to the hydroxyl group (-OH) of cholesterol reacting with the reagents and increasing the conjugation of the un-saturation in the adjacent fused ring.
Since this test uses acetic anhydride and sulfuric acid as reagents, caution must be exercised so as not to receive severe burns.
After the reaction is finished, the concentration of cholesterol can be measured using spectrophotometry.