Haemoglobin estimation--reliability of the copper sulphate specific gravity v. the cyanmethaemoglobin colorimetric method.

Automated colorimetric and copper sulphate (4 solutions with different specific gravities) methods were used to examine 218 blood specimens. The correlation between the two was high (r = 0.82)--proving that the copper sulphate method is reliable for haemoglobin screening. Copper sulphate gives better results in the higher haemoglobin region, which includes the majority of healthy people. In the lower haemoglobin region this method generally gives lower results than the cyanmethaemoglobin method. Copper sulphate is also by far the cheapest means currently available for mass screening.