DOI: 10.36347/sjams.2015.v03i06.021

Pages: 2262-2269

Methaemoglobin results from oxidation of the iron moieties in haemoglobin from the ferrous (Fe2+) to the ferric (Fe3+) state. Methaemoglobin levels in humans are maintained at 1-2% by the methaemoglobin reductase enzyme sysytem.This enzyme reduces haemoglobin iron by trnasfer of an electron from NADH to oxidize cytochrome b5;cytochrome b5 then converts ferric iron to ferrous iron by direct interaction with haemoglobin. Methaemoglobinaemia occurs when the reductase enzyme system is overwhelmed and there is sustained elevated methaemoglobin in the circulation. Methaemoglobin is not compatible with life and should be prevented. It can be hereditary or acquired methaemoglobinaemia.