Tetramethylbenzidine--a sensitive stain for haemoglobin electrophoresis.

A previously undescribed method is presented for staining citrate agarose films for electrophoresis of haemoglobin types using tetramethylbenzidine. This stain is noncarcinogenic and is considerably more sensitive than other commonly used stains, enabling abnormal haemoglobins at concentrations of 1% to be detected. The technique has been applied to screening neonates for haemoglobin S and other haemoglobinopathies after an initial test using cellulose acetate electrophoresis and Ponceau S staining has detected an abnormality.