Urine reagent strips are normally adequate for urine screening, but occasionally, it may be necessary to perform a secondary procedure to ensure the accuracy of the test result. Confirmatory or secondary procedures are usually performed for one or more of these reasons:

• To confirm a result that has been obtained on the reagent strip.
• To obtain a result from a highly pigmented urine that masks the result on the reagent strip.
• To test for a specific analyte (or analytes) that are not included in the specificity of the reagent strip test. For example, the glucose reagent strip test is specific for glucose, but you want to test for other reducing substances.