CALIBRATION OF THE AMERSHAM-FERRITIN-RIA KIT USING THE WHO HUMAN LIVER FERRITIN INTERNATIONAL STANDARD 80 602/

A commercial ferritin kit (Amersham Ferritin RIA (A)) was calibrated u sing the WHO human liver ferritin international standard 80/602 (W). T he reconstituted WHO freeze-dried standard was diluted to obtain five concentration levels ranging from 10-800 mu g/l. Logarithmic transform ation of the values was performed in order to stabilize the variance, yielding the regression equation: logA = 0.0235 + 1.0022 logW. The slo pe of the regression line (being very close to, and not significantly different from, one) was set to one, and the relation between the untr ansformed values then became a proportionality: A = 1.067 x W. A WHO s tandard ferritin value of 15 mu g/l (often used as cut-off value for a bsent iron reserves) and of 30 mu/l (often used as threshold value for the presence of stainable marrow haemosiderin iron) yielded calculate d Amersham Ferritin RIA values of 16.0 mu g/l and 32.0 mu g/l.