Eye chart smaller towards the bottom of the chart. The person removes any glasses or contact lenses, and stands or sits a standardized distance from the chart (e.g., 20 feet for the Snellen chart). The person is then asked to identify the optotypes on the chart, starting with large rows and continuing to smaller rows until the optotypes cannot be reliably identified any more. The row in which the person can reliably identify symbols defines the visual acuity. One eye is tested at a time. Practically, this is accomplished by covering the other eye with a hand, piece of paper, or a
Clinical urine tests Clinical urine tests Clinical urine tests are various tests of urine for diagnostic purposes. The most common is a urinalysis (UA), one of the most common methods of medical diagnosis. The word is a portmanteau of the words "urine" and "analysis". Other tests are urine culture (a microbiological culture of urine) and urine electrolyte levels. The target parameters that can be measured or quantified in urinalysis include naked-eye (gross) examination for color and smell plus analysis for many substances and cells, as well as other properties, such as specific gravity. A part of a urinalysis can be performed by using