An assay and kit for detecting N-retinylidene-N-retinylethanolamine (A2E) in a sample that uses a lipid binding protein, such as Saposin B, to capture A2E in the sample and assist in the extraction and measurement of A2E via mass spectroscopy. A2E thus serves as a marker for macular degeneration so that the assay and kit of the invention can be used to detect the presence or severity of macular degeneration.
