Abstract: Diagnostic test strips for the qualitative detection and semi-quantitative estimation of blood and hemoglobin in biological products include a reagent area comprising an organic hydroperoxide or salt thereof, a chromagen and a novel agent capable of accelerating the peroxidase activity of hemoglobin. The accelerating agent is an aromatic hydrocarbon of the general formula ##SPC1##Wherein R.sub.1 - R.sub.7 are hydrogen or alkyl or alkoxy groups having 1-2 carbon atoms. The resultant test strips evidence marked enhancement in sensitivity as compared with prior art materials.