Some analytes are degraded by exposure to light. Samples that are collected for measuring these analytes should be adequately protected from both direct sunlight and indirect artificial light sources. This list is not meant to be comprehensive, but some of the measurands affected negatively by exposure to light are:
- Bilirubin
- Vitamin A (retinol)
- Urinary citrulline
- Urinary porphyrins
- Urinary urobilinogen
- Urinary delta-aminolevulinic acid
