In light-sensitive specimen handling, which items require protection from light during storage?

• A. Bilirubin and some carotenoids
• B. Sodium and potassium
• C. Calcium and magnesium
• D. Albumin and globulin

Answer: (A)

Light exposure can alter some laboratory analytes, changing their concentrations and leading to inaccurate results. Bilirubin is highly photosensitive and breaks down when exposed to light, which can distort bilirubin measurements. Carotenoids, such as beta-carotene, similarly degrade or change forms with light, affecting their measured levels. Because of this, samples containing bilirubin or carotenoids are stored protected from light to preserve accuracy.

In contrast, the other listed substances—electrolytes like sodium and potassium, minerals like calcium and magnesium, and proteins such as albumin and globulin—are not typically affected by light during standard storage, so they do not require light protection in the same way.