Ferene-S as the chromogen for serum iron determinations.

Ferene-S was tested as the iron chromogen and the results were compared with the chromogen Ferrozine. With Ferene-S the volume of serum could be halved. We also tried to adapt Ferene-S in total iron binding capacity determinations but failed. From the interfering substances in serum iron determination the effects of bilirubin, copper and zinc were tested. Bilirubin was not observed to have any effect on iron values with Ferene-S or Ferrozine as chromogens. Copper ions had a distinct additive effect with both chromogens, but it could be eliminated by the addition of thiourea to the solutions. Zinc had no effect.