Methaemoglobin

Methemoglobin (also known as ferrihemiglobin) is a form of the oxygen-carrying hemoproteinhemoglobin, which is found in the red blood cellsof mammalsand other animals. Unlike normal hemoglobin (Fe²⁺), methemoglobin (Fe³⁺) cannot bind oxygen. Cells use the enzymemethemoglobin reductase to convert the methemoglobin to hemoglobin.

In humans, 1-2% of the total hemoglobin is methemoglobin. Higher percentages can be caused by genetics or by exposure to various chemicals, and may cause health problems. A higher level of methemoglobin will tend to cause a pulse oximeterto read closer to 85% regardless of the true level of oxygen saturation.

Methemoglobinaemia

Methemoglobinaemia is a clinical condition arising from the excessive conversion of hemoglobin to methemoglobin, which is incapable of binding and carrying oxygen.

Methemoglobinaemia occurs when hemoglobin is oxidized at a rate exceeding the normal enzymatic capacity for hemoglobin reduction. Certain individuals with impaired enzymatic capacity for hemoglobin reduction may be susceptible to milder oxidative stresses. Numerous agents may be responsible for this oxidation.da:Mæthæmoglobin

This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Methaemoglobin Wikipedia article Methaemoglobin.