Direct cyanmethemoglobin method has been the gold standard for hemoglobin estimation but other methods like hemoglobin color scale, Sahli technique, Lovibond-Drabkin technique, Tallqvist technique, copper-sulfate method, HemoCue and automated haematology analyzers are also available.
What is the principle of the Cyanmethemoglobin method?
Cyanmethemoglobin Method The principle of this method lies in conversion of hemoglobin to cyanmethemoglobin by the addition of Potassium cyanide and ferricyanide whose absorbance is measured at 540 nm in a photoelectric calorimeter against a standard solution.
Why is Cyanmethemoglobin method considered to be the best method for hemoglobin assay?
The haemoglobin is estimated with the help of cyanmethemoglobin curve. The advantages of this method are i) error due to subjective visual matching is avoided as spectrophotometer is used and hence reading is precise and reliable, ii) measures all forms of haemoglobin except sulphaemoglobin.
Why is Tallquist method no longer used?
The Tallquist method was included at first, but since blood hemoglobin values between 60 and 100 per cent could not be read with any degree of certainty, it was discarded as being inadequate for routine clinical work.
Why N 10 HCl is used in Hb estimation?
The principle of Sahli’s Method or Acid hematin method is quite easy that when the blood is added to N/10 Hydrochloric acid (HCl), the hemoglobin present in RBCs is converted to acid hematin which is a dark brown colored compound.
Why is Cyanmethemoglobin method recommended?
This method is optional for the estimation of hemoglobin and this method is recommended by the International Committee for Standardization in hemotology. This is because in this method all type of hemoglobin is transformed to cyanmethemoglobin (except sulfhemoglobin), and a firm and trustworthy standard is available.
What is hemoglobin and also write the procedure of estimation of hemoglobin by Cyanmethemoglobin method?
Cyanmethemoglobin method This is the internationally recommended method for determining hemoglobin. Principle: Blood is diluted in a solution containing potassium cyanide and potassium ferricyanide. The latter converts Hb to methemoglobin which is converted to cyanmethemoglobin (HiCN) by potassium cyanide.
Is the Tallquist method accurate?
When compared to the Haemoglobin Cyanide method, the Tallquist method showed a calculated sensitivity of 96.6%, specificity of 87.4%, positive predictive value of 86.0%, and negative predictive value of 97.0% and diagnostic accuracy of 91.5%.
What is alkaline Haematin method?
PRINCIPLE: When a blood sample is added to an alkaline solution containing a non-ionic detergent, haemoglobin is converted to alkaline haematin which is a stable colour compound. The absorbance of alkaline haematin is measured using Colorimeter, Haemoglobin Meter or Clinical Chemistry Analyser..
