Abstract: A method of identifying fluid retention in a body part of the patient by directly or indirectly measuring a first parameter relating to a size of a body part of the patient to obtain an actual measurement of the body part, obtaining an estimated measurement of said first parameter relating to the size of the body part of the patient by measuring alternative predefined parameters of the patient, wherein said estimated measurement is calculated based on a mathematical relationship between said alternative parameters and the size of the body part; and correlating the actual and estimated measurements of the body part of the patient to assess any fluid retention in the body part.