Question

What is Sahli's method ?

Answer 1

Hint: Sahli’s method is a way to determine the haemoglobin in blood. Sahli’s haemoglobinometer is used to determine haemoglobin content in blood samples by converting haemoglobin into hematin acid and then diluted produces hematin acid colour which matches with the comparator.

Complete answer:
Sahli's method is a rapid process used to measure or determine the quantity of haemoglobin in blood. Haemoglobin is a component of blood which is responsible for oxygen carrying throughout the body. This method was invented by british neurologist William Gowers(1845-1915).
Haemoglobin is composed of two parts – haem and globin protein. Haem consists of iron and protoporphyrin. It is based on a comparison of the colour of the tested blood sample. The device used is called sahli’s haemoglobinometer and contains hemoglobin tube, pipette, stirrer, & comparator.
The principle for this method is that a blood sample is added to N/10 hydrochloric acid; haemoglobin present in RBCs is converted to acid hematin which forms a dark brown coloured substance. The acid hematin is diluted with water till the dark brown coloured substance matches with comparator brown glass standard. The colour can be measured with scale provided.
The concentration of haemoglobin is determined either as a percentage of normal or better absolute figure in gm/dl.

Note:
It is also known as Acid hematin method in which blood is mixed with acid solution of hydrochloric acid and hemoglobin of blood sample converted to hematin acid showing brown to dark brown coloration. That brown colour of acid hematin can be compared with the scale provided with the comparator.