Hello, If there are two eggs in an eggbox which has a capacity to hold six eggs then the box is 30%full; you don't multiply the box by it's capacity. Hence, % saturation is ([iron]/[transferrin]*100. The reference range will depend on the ratio between transferrin expressed as 'g' and 'mols'. John Martin (retired) ------ACB discussion List Information-------- This is an open discussion list for the academic and clinical community working in clinical biochemistry. Please note, archived messages are public and can be viewed via the internet. Views expressed are those of the individual and they are responsible for all message content. ACB Web Site http://www.acb.org.uk Green Laboratories Work http://www.laboratorymedicine.nhs.uk List Archives http://www.jiscmail.ac.uk/lists/ACB-CLIN-CHEM-GEN.html List Instructions (How to leave etc.) http://www.jiscmail.ac.uk/