Value of Kleihauer testing after administration of anti-D immunoglobulin

The standard dose of 500 IU of anti-D immunoglobulin given in Britain to Rh D negative mothers postnatally is lower than that used in Europe, the United States, and Canada, where 1000-1500 IU is the routine dose. In Britain a Kleihauer test is performed after the 500 IU dose is given.1 The results of this test should indicate the volume of fetomaternal haemorrhage that has occurred and whether a further dose of anti-D immunoglobulin is required. Kleihauer testing is not performed routinely in Europe, the United States, or Canada as the higher dose of anti-D immunoglobulin used prevents Rh sensitisation in all but 0.3% of cases. Use of the Kleihauer test in Rh D negative mothers who have been given anti-D immunoglobulin is intrinsically incorrect as the test measures fetal haemoglobin and not …