Insulin-like growth factor I measurement on filter paper blood spots

The measurement of insulin-like growth factor I (IGF-I) from extracted whole dried blood spots on filter paper is a simple method allowing sample collection to be carried out by the patient at home. One drop of blood is applied to a filter card, air dried and posted to the laboratory. The IGF-I is dissociated from its binding protein by an acidification and neutralization procedure, and IGF-I is then measured by an enzyme-linked immunosorbent assay. Results from the analysis of IGF-I using blood spots on filter paper compared favourably with those from conventional methods, thus showing it to be an ideal and cost-effective technique for the measurement of IGF-I in both adults and children.