Abstract: The present invention involves a composition and method for the determination of enzymatic activity or enzyme substrate concentration in a fluid test sample in which the enzyme catalyzes a reaction in a reagent system to provide a detectable response indicative of the concentration of the enzyme or enzyme substrate in the test sample. A measured amount of a protease capable of eliminating the enzymatic activity is included in the reagent composition, so that when a measured amount of test sample is treated, the reaction producing the detectable response will have a definite end point. The invention is particularly useful in conjunction with the determination of leucocytes in urine wherein the leukocytes are lysed to release their human leucocyte elastase which hydrolyzes a chromogenic ester to provide a phenol which then reacts with a diazonium salt to form a colored azo dye.

Abstract: Disclosed is an improvement in the method of determining protein in an aqueous fluid such as urine by contacting the fluid with a reagent system of a buffer and a protein error indicator. The improvement involves carrying out the determination in the presence of a glass/cellulose combination.

Abstract: Disclosed is an test for the detection of protein in urine by the use of a reagent system containing a buffer and a protein error indicator. The method involves the use of tartaric acid as cation sensing buffer in combination with a non-cation sensing buffer as the buffer system in order to reduce the incidence of false positive results while using less total buffering material.

Abstract: A test device for determining the presence of leukocyte cells, esterase or protease in a test sample is disclosed. The test device comprises a carrier matrix having a reagent composition incorporated therein, wherein the reagent composition comprises a lactate ester having the structure ##STR1## wherein A is an alcohol blocking group, and wherein B--O-- is a residue of compound B--OH and provides a detectable response when the lactate ester is hydrolyzed; and a buffer. In a preferred embodiment, the lactate ester has the structure ##STR2## wherein X is O, S or NR.sup.2, R is aryl or lower alkyl, R.sup.1 is hydrogen or lower alkyl, and R.sup.2 is hydrogen, lower alkyl or aryl.

Abstract: A composition and method for determining the presence of leukocyte cells, esterase or protease in a test sample are disclosed. The composition contains a lactate ester having the structure ##STR1## wherein A is an alcohol blocking group, and wherein B-O- is a residue of compound B-OH and provides a detectable response when the lactate ester is hydrolyzed; and a buffer. One class of lactate ester has the structure ##STR2## wherein X is O, S or NR.sup.2, R is aryl or lower alkyl, R.sup.1 is hydrogen or lower alkyl, and R.sup.2 is hydrogen, lower alkyl or aryl.