impede the liberation of the esterases. Detection limit The detection limit of a test is the concentration at which the test starts to turn from negative to positive. Although the detection limit may vary between urine samples, the detection limit is defined as the concentration of the analyte that results in a positive reaction in 90% of the examined urines. Medical uses Urine test strips can be used in many areas of the healthcare chain including screening for routine examinations, treatment monitoring, self-monitoring by patients and/or general preventive medicine. Screening Urine test strips are used for screening both in hospitals and in general practice. The aim of screening is early identification of likely patients by examination of large groups of the population. The importance of screening for diabetes and kidney disease amongst high-risk populations is becoming very high. Treatment monitoring Treatment monitoring with the aid of urine test strips allows a health professional to check on the results of the prescribed therapy, and if necessary to introduce any changes into the course of therapy. Self-monitoring Self-monitoring with urine test strips under the guidance of a health professional is an effective method for monitoring the disease state. This applies particularly to diabetics, where the idea of self-monitoring of the metabolic status (determinations of glucose and ketones) is self-evident. Veterinary In veterinary medicine, especially in cats and dogs, the test strip can be used for urinalysis. History In many cultures urine was once regarded as a mystical fluid, and in some cultures it is still regarded as such to this day. Its uses have included wound healing, stimulation of the body's defences, and examinations for diagnosing the presence of diseases. It was only towards the end of the 18th century that doctors interested in chemistry turned their attention to the scientific basis of urinalysis and to its use in practical medicine. 1797 - Carl Friedrich Gärtner (1772–1850) expressed a wish for an easy way of testing urine for disease at the patient's bedside. 1797 - William Cumberland Cruikshank (1745–1800) described for the first time the property of coagulation on heating, exhibited by many urines. 1827 - English physician Richard Bright describes the clinical symptom of nephritis in “Reports of Medical Cases.” 1840 - The arrival of chemical urine diagnostics aimed at the detection of pathological urine constituents 1850 - Parisian chemist Jules Maumené (1818–1898) develops the first “test strips” when he impregnated