Spectrophotometric plasma iron determination from fingerpuncture specimens.

A simple, sensitive, precise and reproducible micromethod for the determination of plasma iron in a 50-microliter sample has been devised by modification of the ICSH reference procedure, which requires a 2-ml sample. The micromethod uses microcuvettes and substitutes ferrozine for the bathophenanthroline chromogen of the ICSH. Comparison of plasma iron values on 47 paired specimens obtained by fingerpuncture and venipuncture determined by the micro- and ICSH-methods respectively gave identical means of 15.8 mumol/l (88 microgram/dl); the correlation of the two methods was r = 0.92 (p less than 0.0001). The micromethod has been successfully used to measure plasma iron levels in fingerpuncture specimens collected in a field study of 429 children.