The ELISA (enzyme-linked immunosorbent assay) is a test which uses color change and antibodies to identify a substance. An indirect ELISA is one of three ELISA tests.
Urine varies in appearance, depending principally upon a body's level of hydration, as well as other factors. Normal urine is a transparent solution ranging from colorless to amber but is usually a pale yellow. In the urine of a healthy individual the color comes primarily from the presence of urobilin.
The first of the physical properties to be considered is color. The color of urine often varies with its concentration and is most often reported as some shade of yellow (straw, light yellow, yellow, dark yellow, and amber). Normal urine can be found in any of these colors, with the exception of the âamberâ color.