the matrix portion of the finished test devices was momentarily immersed in and withdrawn from urine samples containing various levels of intact red blood cells the test composition was found to react with intact red blood cells to produce green to blue dots or flecks on the impregnated paper thus indicating a positive reaction this test composition was found to be sensitive down to a level of 2 to 5 intact red blood cells per microliter of urine which corresponds to a blood dilution of about 1 1 000 000 similarly prepared test compositions were found to be equally sensitive to hemolyzed blood cells but reacted by uniformly coloring the impregnated paper following the method for preparing the acid salt or adduct described in example 1 6 methoxyquinoline was suspended in ethanol and mixed with 50 ml of ethanol containing 7 grams of sulfosalicylic acid the precipitate which formed was similarly separated washed and dried the recovered material was identified as 6 methoxyquinoline sulfosalicylic acid salt having a melting point of 225 u00b0 c improved test compositions were then prepared in accordance with the description of example 1 replacing the quinoline sulfate with 0 75 grams of 6 methoxyquinoline sulfosalicylic acid salt the sensitivity to intact red blood cells and hemolyzed blood of test devices incorporated with this test composition was found to be of the same order as the test devices of example 1 in accordance with example 1 improved test compositions were prepared by replacing the quinoline sulfate with one of the acid salts or adducts listed below ______________________________________acid salt or.