Given a regular chain T , we aim at finding an efficient way for computing a system of generators of sat(T ), the saturated ideal of T . A natural idea is to test whether the equality T = sat(T ) holds, that is, whether T generates its saturated ideal. By generalizing the notion of primitivity from univariate polynomials to regular chains, we establish a necessary and sufficient condition, together with a Gröbner basis free algorithm, for testing this equality. Our experimental results illustrate the efficiency of this approach in practice.