The reactive paper is made of cellulose filter
paper dipped into bromothylmol blue and
acetylcholine chloride. Bromothymol blue is
used as color indicator and acetylcholine chloride
as a substrate for cholinesterase enzyme.
The results of the reactive-paper tests were
visualized in four colors, which the manufacturer
the tube to test serum ChE level with reactive
paper. After use, the results were controlled by
annotating the product labels; the reactive paper
was then stored in an icebox to maintain the
quality of the paper, due to its sensitivity to
elevated temperatures.