Technical details about Phadebas® Amylase Test

A Phadebas® tablet consists of homogeneously interlinked starch polymers, taking the form of globular microspheres of defined size. These Bio-Degradable Starch Microspheres (DSM) are insoluble in water. To the DSMs, a blue dye is covalently bound. When the dye is bound to the microsphere, it remains water insoluble. However, in the presence of Amylase, the DSM is degraded at a speed proportional to the Amylase activity, and the blue dye is liberated. The characteristics of the now liberated blue dye molecule is the key for Phadebas action. The free dye molecule is water soluble and its concentration measurable at 620 nm. Using a fixed assay time, the absorbance reading gives the solution's Amylase activity, through the standard curve supplied with each kit. 

In the qualitative forensic assay, the diffusion of the liberated dye molecules is used to indicate the likely presence of salivary Amylase.

In semi-quantitative assays, such as Analis's Isoamyl assay, the blue dye is used for visual detection. After electrophoretic separation of the various subclasses of salivary and pancreatic Amylases, Phadebas® tablets are dissolved on top of the gel. Where Amylase activity degrades the DMSs, the free dye diffuses into the gel, while non-degraded DSMs (and dye) is washed away. The remaining colored spots reveal the Amylase pattern, for diagnostic purposes.

The picture shows a 3D model of alpha-amylase