The measurement of serum free insulin by steady-state gel filtration

A method for the separation of bound and free insulin in the serum of insulin treated diabetics by steady state gel filtration is described. The method meets the criteria which have been suggested for the validation of a method of separating bound from free ligand. The precision of the method is satisfactory, and the results compare well with those obtained by the methods of ethanol precipitation and polyethylene glycol precipitation.