Medical workers use dry reagent strips, or "dipsticks," to detect excretions in the urine that indicate disease. Different strips can test for different excretions--and therefore different diseases, from inadequate insulin to cancer. Test strips come in containers with colour charts to which you would compare the test strip. They also come with colour charts on flat cards for alternative comparison. Mechanical readers are also available, and deemed more accurate than manually reading the strip.
Collect fresh urine in a dry, clean vessel.
Remove one reagent strip from its container and immediately close the container again, to prevent the surrounding air from affecting the other strips' colour.
Dip the reaction area of the strip into the urine, simultaneously starting a timer. Make sure the strip is well-saturated. Wipe the edge (not the broad side) of the strip on the edge of the urine vessel to remove excess urine.
Lay the strip alongside the colour chart and find the colour in the chart that the strip matches 60 seconds after the initial dipping. Use good light, such as fluorescent light, to see well. (Although the fluorescent light can affect how the colours look, both the chart and the strip will be affected, and comparison of colours is what matters.) Don't lay the strip on the chart, as that will soil the chart for future use.
There will be exceptions to the 60-second rule depending on the brand and substance being tested for. Read all Combur-7 strips at 60 seconds. For Multistix 8, read for glucose at 30 seconds, specific gravity at 45 seconds, and leukocytes at two minutes; otherwise, read it at 60 seconds. The chart should tell you how long to wait before reading.
Note that colour-blind technicians should not perform these tests. Too many colours will look similar. See the Canterbury District Health Board link below for other sources of error listed by substance being tested for.