a strip of merino wool with “tin protochloride” (stannous chloride). On application of a drop of urine and heating over a candle the strip immediately turned black if the urine contained sugar. 1883 - English physiologist George Oliver (1841–1915) markets his “Urinary Test Papers” approx. 1900 - Reagent papers become commercially obtainable from the chemical company of Helfenberg AG. 1904 - A test for the presence of blood by a wet-chemical method using benzidine became known. approx. 1920 - Viennese chemist Fritz Feigl (1891–1971) publishes his technique of “spot analysis". 1930s - Urine diagnostics makes major progress as reliability improves and test performance becomes progressively easier. 1950s - Urine test strips in the sense used today were first made on industrial scale and offered commercially. 1964 - The company Boehringer Mannheim, today Roche, launched its first Combur test strips. Even though the test strips have changed little in appearance since the 1960s, they now contain a number of innovations. New impregnation techniques, more stable colour indicators, and the steady improvement in colour gradation have all contributed to the fact that the use of urine test strips has now become established in clinical and general practice as a reliable diagnostic instrument. The parameter menu offered has steadily grown longer in the intervening decades. Ascorbic acid interference Ascorbic acid (vitamin C) is known to interfere with the oxidation reaction of the blood and glucose pad on common urine test strips. Some urine test strips are protected against the interference with iodate, which eliminates ascorbic acid by oxidation. Some test strips include a test for urinary ascorbate. Urinary sediment During routine screening, if a positive test for leukocytes, blood, protein, nitrite, and a pH greater than 7 is identified, the urine sediment may be microscopically analysed to further pinpoint a diagnosis. Automated analysers Automatic analysis of urine test strips using automated urine test strip analysers is a well-established practice in modern-day urinalysis. They can measure calcium, blood, glucose, bilirubin, urobilinogen, ketones, leukocytes, creatinine, microalbumin, pH, ascorbic acid and protein. References Further reading Compendium Urinalysis: Urinalysis with Test Strips. Dr E F Hohenberger, Dr H Kimling (2002)http://www.diavant.com/diavant/servlet/MDBOutput?fileId=1392 Urinalysis Strips Instructions Urine tests