Methaemoglobin

Keywords: MetHb

Specimen:

5 mL blood in EDTA.

Method:

Spectroscopic screening and spectrophotometric quantitation.

See also Haemoximetry.

Reference Interval:

Methaemoglobin < 1% of total haemoglobin in normal blood, slightly higher in infants, particularly if premature.

Application:

Investigation of unexplained central cyanosis; possible oxidant drug haemolysis (eg, sulphonamides, aniline dyes, nitrates and nitrites).

Interpretation:

Increased levels of methaemoglobin are seen in patients with Haemoglobin M haemoglobinopathy or methaemoglobin-reductase deficiency and following oxidant drug exposure.

See also Heinz body.

Reference:

Bradberry SM. Toxicol Rev 2003; 22(1): 13-27.