Assessment of size of small volume feto-maternal bleeds. A new method of quantification of the Kleihauer technique.

The risk of Rh-isoimmunization is probably related to the volume of foeto-maternal bleeding. With the Kleihauer technique foetal cells may be detected in maternal blood, but estimation of the size of foetal bleed the cells represent is at present difficult and open to serious error.A new method of quantifying the technique by using a standard volume of maternal blood, and a simple machine for the preparation of comparable blood films, is described. The new method eliminates many of the errors of previous techniques, and should be capable of automation for large-scale screening programmes.