The ability to cure or manage devastating diseases such as cancer and dementia is highly dependent on their molecular diagnosis at the earliest time point possible. Recent technological developments have spurred the search for circulating protein biomarkers of various diseases; however, serum and plasma are extremely challenging samples owing to the wide dynamic range of protein concentration. Fractionating these samples into simpler aliquots has proven to be an effective strategy in identifying lower abundant proteins within these samples, which are believed to be the regiment where biomarkers exist. This article describes a method that fractionates serum to isolate low molecular weight proteins. By isolating this fraction, many of the abundant, higher molecular proteins such as albumin and immunoglobulins are eliminated making the identification of lower abundant proteins in serum possible.