The invention relates to a diagnostic gel composition for use as a diagnostic element in diagnostic devices. The diagnostic gel composition is derived from a compound having a formula D-Sp-Po wherein D is a diagnostic group; Sp is a hydrophilic spacer group; and Po is a polymerizable group. The diagnostic gel composition of the invention has dimensions ranging from about 250 nanometers to about 1000 micrometers, and a Young's modulus ranging from about 10 kilopascals to about 200 kilopascals. The invention also provides method for making the diagnostic gel composition. The method comprises providing a composition comprising a porogen, an initiator and a compound having a formula D-Sp-Po; polymerizing the composition to form a polymerized composition; and washing the polymerized composition to form the diagnostic gel composition.