A unitary single use analytic device for detecting an enzyme in a liquid. The device comprises a support structure for manual manipulation and a composition associated therewith which is responsive to the enzyme in such a way as to cause a change in appearance of the device. The device may be adapted for detecting an enzymes from a plurality of classes by having compositions selectively responsive to an enzyme of one class, each responding in such a way as to cause a change in appearance of the device indicative of the presence of an enzyme of a respective class. Also disclosed is a method for estimating the activity of an enzyme in a liquid comprising the steps of inserting a test strip of the present invention into the liquid and measuring the time taken from the moment of insertion until a predetermined change in appearance of the test strip is observed, or noting the appearance of the strip after predetermined time.