Define and Classify Hemoglobin. Give the normal values and function.

Hemoglobin:

Hemoglobin is a conjugated protein, consisting of haem and the protein globin, that gives red blood cells their characteristic colour. It combines reversibly with oxygen and is thus very important in the transportation of oxygen to tissues. 

Shortened from haematoglobulin, from haematin + globulin the two components.

 

Classification of Hemoglobin: There are two types of hemoglobin. The variation occurs only in globin but haem portion is same.

 

• Physiological: Haemoglobin A (Hb A1):   It contains 2α and 2β chain of globin.98% of normal adult.  Haemoglobin A2 (Hb A2):It contains 2α and 2δ chain. 2% of normal adult.  Haemoglobin F(Hb F): It contains 2α and 2γ chain. Normally present in foetus.   Pathological (abnormal haemoglobin): Hb S or sickle cell heamoglobin Hb C or heamoglobin  C Hb M or heamoglobin M

Normal value hemoglobin:

The hemoglobin level 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 gender of the person. The normal ranges are:

• Newborns: 17 to 22 gm/dL
• One (1) week of age: 15 to 20 gm/dL
• One (1) month of age: 11 to 15 gm/dL
• Children: 11 to 13 gm/dL
• Adult males: 14 to 18 gm/dL
• Adult women: 12 to 16 gm/dL
• Men after middle age: 12.4 to 14.9 gm/dL
• Women after middle age: 11.7 to 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. Pregnant females are advised to avoid both high and low hemoglobin levels to avoid increasing risks of stillbirths (high hemoglobin – above the normal range) and premature birth or low-birth-weight baby (low hemoglobin – below the normal range).

 

 

   Function of Hemoglobin:

• It is essentail for transport of oxygen from lung to the tissue and carbondyoxyed from tissue to lungs.
•  It is an important blood buffer  and helps to maintain pH of blood.
• Various pigments of bile, stool, urine etc are derived from it.
• Its reserves iron and portein.