, Volume 89, Issue 2, p 209
Date: 17 Jul 2009

Wrong molar hemoglobin reference values—a longstanding error that should be corrected

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Dear Editor,

The molar weight of hemoglobin is 64 kDa, so 1 mol of hemoglobin has a weight of 64,000 g, and 1 mmol has a weight of 64 g. According to this, the widely stated (e.g., in [1]) normal range of ~7–12 mmol/l expressed in grams per liter would be 7 × 64-12 × 64 g/l = 448–768 g/l = ~45–77 g/dl, and that is in clear conflict with the reference range given in the literature (12–18 g/dl, [2, 3]); moreover, the calculated values are obviously ~4-fold times higher. The often-stated molar concentration of hemoglobin in SI units with a range of 7–12 mmol/l therefore is not right for the molar concentration of the whole hemoglobin molecule, but it is correct for the molar concentration of hemoglobin subunits, given the fact that one hemoglobin molecule is built of four subunits. Moreover, it reflects the molar concentration of the hem groups as well as the molar concentration of iron bound to hemoglobin. The wrong molar concentration reference values in the literature may arise from the ...