Why a phlebotomist should never attempt venipuncture in a patient who shows clear oedema in the arms?

A phlebotomist should avoid performing venipuncture in a patient with clear edema in the arms because the swollen tissue can obscure veins, making it difficult to locate a suitable site for drawing blood. Additionally, puncturing an edematous area may lead to complications such as infection, hematoma, or inaccurate lab results due to altered blood composition. Furthermore, the underlying cause of the edema may indicate a more serious condition that requires medical attention.