Combined silver Perls's stain for differential staining of ringed sideroblasts and marrow iron.

During a study of nucleolar organiser regions, a modified silver stain was found to be a sensitive marker for the iron in ringed sideroblasts, more so than Perls's stain when the marrow iron stores were low. To enhance the usefulness of the silver stain, a combined silver Perls method was developed. This stains the ringed sideroblast iron black and haemosiderin blue, thus rendering the detection of ringed sideroblasts easier even when marrow iron stores are excessive. AT the same time, it allows marrow iron content to be evaluated. The silver reagent in this combined method probably shows phosphate rather than the iron present in the abnormal mitochondria in ringed sideroblasts. This facilitates the differential staining of ringed sideroblast "iron" and haemosiderin.