-- Artificial chemical substances:  In the case of commercial quality control, some of them do not use real ketones(acetoacetic acid) and urobilinogen, but use an artificial chemical substances instead and this makes some difference in result.

-- Chemical reaction in the sample:  Do not dip the test strip more than 5 times into the same one urine specimen.  Very little amount of chemical reagents from the strip pad dissolves in the specimen when dip and it may interfere the reaction of the test strip. (Dropping method shows more stability comparing with dipping method)

-- Excess urine:  The excess urine must be removed from the test strip to avoid Run-over phenomenon in pH test or Window frame in glucose test strip’.

-- Dipping:  When you test with an urine analyzer, you must dip the test strip completely up to the compensation area in order to prevent the error of coloration from urine.