1.2.5 Anatomy, Physiology, and Health Education I Laboratory
Lab 4 Estimation of Haemoglobin with the help of Sahli's Haemoglobinometer (Cont'd...)
Clinical significance of Haemoglobin estimation
i. Anaemia: Haemoglobin estimation below normal level indicates that the patient is anaemic. In this condition there is not enough Hb available to carry sufficient oxygen from the lungs to tissue.
Types of anaemia:
A. Based on haemoglobin estimation: if haemoglobin level is below 10gms/dl it is called mild anaemia. If haemoglobin level goes below 8gms/dl, and 6gms/dl, the conditions are called moderate and severe anaemia respectively.
B. Based on etiology of anaemia: Deficiency of iron in diet (iron deficiency anaemia), Vitamin B12 and Folic acid are deficient in diet or folic acid is destroyed due to drug's action (Megaloblastic anaemia), Due to impaired absorption of Vitamin B12 from the small intestine, as the intrinsic factor is not synthesized by stomach or destroyed due to gastric surgery (Pernicious anaemia), Synthesis of Hb is impaired due to bone marrow failure (Hypoplastic or aplastic anaemia), destruction of Hb in circulation due to effect of drugs, free radicals or other toxic chemicals (Hemolytic anaemia). Haemoglobin A is replaced by Hb S, Hb C, Hb D, and Hb E (hereditary haemoglobinopathies, Sickle cell anaemia etc.), Haemoglobin Batrs (consists of four gamma chains) is present
in stead of normal Haemoglobin (Thalassemia).
ii. Polycythemia: When RBC count is elevated sometimes in disease condition like haemoconcentration due to burns, cholera, chronic heart disease, conditions of decreased lung function such as emphysema or due to climbing (as the oxygen level is less in the high altitude).
Methods of Haemoglobin count:
1. Visual colour comparison method
i. Sahil's method ii. Dares method iii. Hadens method iv. Wintrobes method
v. Haldanes method vi. Tallquists method
2. Gasometric method
Van Slyke method
3. Spectrophotometric method
i. Oxyhaemoglobin method ii. Cyanmethemoblobin method
4. Automated haemoglobinometry
5. Non-automated haemoglobinometry
6. Other methods:
i. Alkaline-hematin method ii. Specific gravity method iii. Comparator method.
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