Indicating device and method for the determination of cholinesterase activity in the serum

摘要

A means for determining the cholinesterase content of serum comprises an absorbent vehicle impregnated with a substrate for cholinesterase and phenol red. Preferably naphtholphthalein is also present. The vehicle may be filter paper, glass fibre paper, silica gel or alumina, and the specified substrates are acetylcholine, or the hydrochloride, hydrobromide or sulphate thereof. The substrate and indicator may be applied to the vehicle together as a solution in an organic solvent (methanol, ethanol, i-propanol, acetone, dioran, tetrahydrofuran), mixed if desired with water. The solution should have a pH of 5-8.5: where acidic salts of acetylcholine are used, NaOH, Na2CO3 or NaHCO3 or the corresponding K compounds may be added; where free acetylcholine is used, HCl may be added. The indicator and substrate may alternatively be added to the substrate separately. A definite amount of serum and a test device are brought together and after a specific time at a specific temperature the colour is compared to a previously calibrated colour scale.