The 3.5% phosphotungstic acid solution is of particular importance in histology due to its ability to facilitate the binding of dyes to tissue. This occurs through the formation of insoluble varnishes, which stabilize the binding of the dye to tissue and prevent the dye from being dissolved out during subsequent staining and treatment processes.

The specific suitability of phosphotungstic acid for this task results from its chemical properties. As a strong oxidant and proton donor, it poses divalent metal ions (W2+) interact to form stable complexes.

The practical application of phosphotungstic acid extends beyond histology. As noted in various scientific publications, phosphotungstic acid has applications in other areas of biological and medical research. For example, it is used in medical laboratory diagnostics to detect or quantify specific types of biomolecules.