To check residual, push plunger in syringe, insert in tube and pull. Right now, nurses don't seemto agree on what's too much. One says full syringe, another says multiples, one says ask the nutritionist. I have a booklet, but the spaces listing acceptable residual amount weren't filled out. Booklet does say a jejunostomy tube should have little or no residual,so may not be necessary to check it. booklet also tells you to check for residual, but doesn't say how ("ask your healthcare professional . . "). Nurse did tellme to be sure to push residual back in, because it contains needed electrolytes.