1.1 ,The gel content of pipe and tubing produced from crosslinked polyethylene plastics as described in Specification F876 and other pipe or tubing standards is determined by extracting with solvents such as xylenes. A test method for quantitative determination of gel content is described herein. The method is applicable to PEX pipe and tubing of all densities, including those containing fillers, and provides correction for the inert fillers present in some of those compounds.