Question

4.  POC Instrument measurement mechanism,

Describe the mechanism or methodology (principle of operation) used in this device for your chosen analyte (i.e. colorimetric, photometric). Describe the actual measurement process. How is your analyte measured? Explain what specific reagents are used, what they do, and indicate what units are reported (i.e. mg/dl).

in this case, analyte is hemoglobin

Answer 1

Answer : Haemoglobin estimation by sahlis method ( photometric )

Principle :

• Hemoglobin is converted by HCL into acid haematin which gives Brown color to solution .
• This color of the solution is matched with the colour of the comparator of sahlis haemoglobinometer.

Measurement process :

• N/ 10 HCL is taken up to 20 mark of the gratuated tube .
• About 20 micro liters  of blood is taken in the hemoglobin pipette.
• The tip of pipette is wiped with blotting paper.
• The blood is added to the HCL in the hemoglobinometre tube .
• Wait for 10 minutes and then add distilled water drop by drop till the colour matches with the colour of comparator of sahlis haemoglobinometer .
• Haemoglobin is expressed in gm%.

Reagent used for sahlis method :

N/10 HCL .

Normal levels of Hb :

1. Adults : 12-16 gm%.
2. Children : 12 to 14 gm%.
3. Infants : 16 to 22 gm %