1. Non-protein-bound iron has been implicated in the aetiology of chronic lung disease of prematurity.
2. The modification of a method for the measurement of non-transferrin-bound iron in small volumes of plasma and bronchoalveolar lavage fluid from preterm babies is described.
3. The assay runs with a good degree of precision and a lower limit of detection of 0.02 μmol/l.
4. Non-transferrin-bound iron was detected in 50% of plasma samples and 11% of bronchoalveolar lavage fluid samples collected over the first week of life from babies born prematurely.