Definition of Hb (hemoglobin)

Hb (hemoglobin): Hb is the standard abbreviation for hemoglobin, the oxygen-carrying protein pigment in the blood, specifically in the red blood cells.

In the very common laboratory test for hemoglobin (Hb), it is measured as total hemoglobin and the result is expressed as the amount of hemoglobin in grams (gm) per deciliter (dl) of whole blood, a deciliter being 100 milliliters.

The normal ranges for hemoglobin depend on the age and, beginning in adolescence, the sex of the person. The normal ranges are:

• Newborns: 17-22 gm/dl
• One (1) week of age: 15-20 gm/dl
• One (1) month of age: 11-15gm/dl
• Children: 11-13 gm/dl
• Adult men: 14-18 gm/dl
• Adult women: 12-16 gm/dl
• Men after middle age: 12.4-14.9 gm/dl
• Women after middle age: 11.7-13.8 gm/dl

All of these values may vary slightly between laboratories. Some laboratories do not differentiate between adult and "after middle age" hemoglobin values.