How long will the lines remain visible?
The test should be read within 10 minutes for best results. A positive (SURGE) result will never disappear. The color band may become darker and a tinted result will never disappear. The color band may become darker and a tinted background may appear after several hours. Some negative results may later display a faint second color band because of evaporation from the test window which prevents complete migration of the test chemicals. Therefore, you should discard the test card once you have read the result.
