The CuSO4 gravimetric test has been the me-thod of choice for the primary Hb screening of potential blood donors for many years.
Although very anemic donors can, on occasion, pass the CuSO4 test [4], There are reports suggesting that the CuSO4 method tends to give inappropriate failures also.
A significant number of such failed donors can be recovered with revised Hb range or if an alternative screening method is applied [5].