Manufacturer’s instructions were followed and due care was taken to standardize all these methods and follow quality assurance procedures.
For the purpose of this study, the Coulter counter was considered as standard reference method.
Daily calibration was done with Hb control samples and inter-laboratory comparison was done at monthly intervals.
The Hb estimation of all the donors was performed by two trained technologist after careful assessment of their performance.
Though the automated hematology analyzer works on the same principle, the Cyanmethemoglobin method was also included in this study since many blood banks in our country cannot afford to have an independent automated hematology analyzer and the Cyanmethemoglobin method (manual) is used for standardization of the copper sulphate method as well.