Abstract: To determine iron in serum by the release of bound iron and reduction of the released iron to Fe.sup.2+, a first solution of a denaturing agent at a concentration of 1 to 8 mol/l is added to the serum, then a second solution is added which contains the color reagent and likewise a denaturing agent at a concentration of 1 to 8 mol/l and subsequently the colored complex is measured photometrically.

Abstract: The present invention provides a process for the determination of iron in body fluids by liberation of the bound iron, reduction to Fe.sup.2+, addition of a color system appropriate for the detection of iron and photometric measurement in a tenside-containing sample solution, wherein a fatty acid polyethylene glycol ester, an alkanol polyglycol ether and at least 1 mole/liter quanidine hydrochloride are added to the sample solution. The present invention also provides a reagent for the determination of iron in serum, containing a reducing agent, a color material system appropriate for the detection of iron and guanidine hydrochloride and at least one tenside, wherein it contains a fatty acid polyethylene glycol ester and a alkanol polyglycol ether.

Abstract: Process for the production of an immune-reactive, porous carrier material for heterogeneous immunological analysis by application to a carrier material of a solution of a receptor and of a component precipitating this immunologically, incubation of the carrier material impregnated with these solutions for the immune precipitation, optional washing and subsequent drying of the impregnated carrier material, wherein the concentrations of the receptor and of the component are so chosen that, in the case of the impregnation, their molar ratio is greater than the ratio defined by the Heidelberger maximum. Also a carrier material for heterogeneous, immunological analysis, wherein it contains a receptor and an immunologically precipitating component in a molar ratio which is greater than the ratio defined by the Heidelbeger maximum.