Abstract: Disclosed herein is a composition useful for stabilizing diagnostic reagent which functions to react with a specimen to determine the presence or absence of a biological condition comprising about 0.01 to 35 parts by weight protein or peptide and either (A) about 1 to 90 parts by weight of a saccharide polyol selected from the group consisting of corn syrup and dextrose and optionally up to about 25 parts by weight of a pyrrol, or (B) about 1 to 90 parts by weight of a saccharide polyol and about 0.01 to 25 parts by weight of a pyrrol. Also disclosed is a method of stabilizing such diagnostic reagents comprising using the stabilizing composition, and a diagnositc device comprising a non-absorbent base carrying at least one deposition area in which is carried the evaporative residue of such diagnostic reagent and the stabilizing composition.