Diaminofluorene is more sensitive than benzidine for detecting hemoglobin in erythropoietin responsive J2E cells.

We have used the diaminofluorene stain to detect hemoglobin production in J2E cells following erythropoietin-induced differentiation. The pseudo-peroxidase activity of hemoglobin produces a colored product, fluorene blue, which can be measured spectrophotometrically. We found that the absorbance varied with time and concentration of hemoglobin, making it unsuitable for rapid, routine use. However, hemoglobin content could be determined from the initial reaction rate and this correlated extremely well with the number of benzidine positive cells. When used as a direct cytochemical stain diaminofluorene was shown to be more sensitive than benzidine in detecting hemoglobin-producing J2E cells.