Padham Health News explains in brief about routine laboratory investigations, the normal values, the implications and the like. Focus is on Haemoglobin in this article.
Haemoglobin – Hb%
Haemoglobin is the pigment that transports oxygen in the blood from lungs to the tissues. Hb is a chromoprotein and is the main component of RBC and this is what gives blood its colour. Haemoglobin combines readily with the oxygen molecule to form the unstable compound, oxy-haemoglobin. Blood with oxy-haemoglobin is observed to be bright red. The haemoglobin content in a blood sample may be determined by measurement of its colour, its power of combining with oxygen or carbon monoxide or by its iron content.
The life span of Hb is same as that of RBC ie. 120 days. 1gm of Hb combines with 1.34ml of Oxygen. The level is expressed as the amount of Hb in gms per decilitre of whole blood. The normal haemoglobin count is 12-16 grams of haemoglobin per deciliter of blood in females and 14-18 grams of haemoglobin per deciliter of blood in males. The Hb levels are slightly higher in children.
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Types of Haemoglobin:
There are many different types of haemoglobin. The main haemoglobin in adult humans is Haemoglobin A and it contains two alpha and two beta subunits. Haemoglobin also transports carbon dioxide away from the tissues to the lungs where it is exhaled. Haemoglobin S, or sickle haemoglobin, is responsible for Sickle Cell Anaemia. Sickle Cell Anaemia and Thalessemia are hereditary blood disorders.
The glycosylated haemoglobin test: – Glucose attached to Haemoglobin is also used to test the diabetic control. When the glucose in the blood attaches to the haemoglobin, glycosylated haemoglobin is formed. These cells stay in circulation for a period of two to three months. Monitoring their level gives an idea about your sugar control in the past two months.
Methods to measure Haemoglobin:
The Haemoglobin Colour Scale was developed by WHO as a simple, accurate, and cost-effective clinical device for the detection and management of anaemia for use in areas where laboratory facilities are not readily available, and for haemoglobin surveys to identify populations at risk. Talqvist used simple filter paper and compared the blood drop colour to printed charts.
Sahli or Acid Haematin Method.
This is the commonest method used to measure Haemoglobin In this method, Haemoglobin (Hb) is converted to acid haematin by the addition of 0.1 N Hydrochloric acid and the resulting brown colour is compared with standard brown glass reference blocks.
Low haemoglobin levels less than 12 grams per decilitres are indicators of Anaemia. Gross reduction of Hb content to less than 6 or 8 grams needs energetic treatment. Hb content is done prior to all major surgeries. Estimation of haemoglobin in injuries reflects blood loss.
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