Multisystem test means, method of making same and method for determining a constituent in a sample under a plurality of reaction parameters. More particularly, a multisystem test means for the determination of a constituent in a liquid sample comprising a plurality of components associated with at least two reaction systems, said reaction system being respectively functional under different reaction parameters, at least one of said components being responsive to the presence of said constituent, and at least one other of said components being effective in response to contact with the sample under reaction parameters at which a first of said reaction systems is functional to change said reaction parameters to those under which at least one other of said reaction systems is functional. The test means, or device incorporated therewith, is contacted with a sample to be tested and after a predetermined time at least one component causes a change in reaction parameters.

A composition for assaying nitrites comprising a diazotizable amine, an acid component and a coupling component, wherein the coupling component is a compound of the following formula I: ##STR1## wherein R represents a hydrogen atom or a straight-chain alkyl group having 1 to 6 carbon atoms, such as a methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl group and n represents an integer of 1 to 6, with the proviso that the sulfoalkyl group may be substituted with at least 1 hydroxyl group, or a water-soluble salt thereof as well as test devices carrying the composition. This composition is far more sensitive than conventional compositions for assaying nitrites. With this composition, for example, a trace amount of as small as 0.02 mg/100 ml of a nitrite to be detected in urine in the diagnosis of a bacterial infection such as urinary tract infection can be detected surely.

A diagnostic test system for detecting .beta.-galactosidase producing micro-organisms is prepared by impregnating one zone of a bibulous material with an aqueous acetone solution of an o-nitrophenyl-.beta.-D-galactopyranoside substrate and evaporating to dryness; and impregnating a contiguous and separate zone of the bibulous material with a solution of a microbiologically inert buffer system which will maintain a pH of from about 6.5 to 8.5 and evaporating to dryness. Preferably, the bibulous material contains 1.5 mg of dry o-nitrophenyl-.beta.-D-galactopyranoside and 0.02 millimoles of a buffer which will maintain a pH of 7.4. Optionally, a waterproof barrier zone and an identifying dye zone may be present. In use, the impregnated bibulous material is inserted into a test tube of a saline suspension of unknown organism and incubated for 4 hours. The development of a yellow coloration indicates that .beta.-galactosidase is produced by the organism being tested. The diagnostic test system of this invention is stable for 1 year at 4.degree.C., at room temperature, and at 37.degree.C.

A method for detecting the presence of nitrite ions in fluids by pretreat nitrite containing fluids to enhance the detectability with nitrite detecting reagents of the nitrite ions therein, which pretreatment step comprises passing the nitrite containing fluids through activated charcoal prior to combination with a nitrite detection reagent. Also a test kit for carrying out the above method.