Hemoglobin Derivatives Hematology Review 299
NORMAL % OF
HEMOGLOBIN CAUSE EFFECT TOTAL HGB OTHER
Methemoglobin Iron oxidized to ferric (Fe3+) Can’t bind O 2. Cyanosis, £1% Heinz bodies. Treat with
state. Usually acquired from possibly death. methylene blue.
exposure to oxidants. Rarely
inherited.Sulfhemoglobin Sulfur bound to heme. O 2 affinity 1/100th 0 Can’t be converted back to
Acquired from exposure to normal. Cyanosis. normal hemoglobin. Not
drugs & chemicals. detected in cyanmethemo-
globin method.Carboxyhemoglobin Carbon monoxide bound ↓O 2 to tissues. Can <1 % Affinity of hgb for CO is
to heme. be fatal. 200× greater than for O 2.
Skin turns cherry red.Hemoglobin derivatives are quantitated by differential spectrophotometry.