What does a positive result on a Kleihauer-Betke stain indicate?

A positive result on a Kleihauer-Betke stain indicates the presence of fetal cells in maternal blood. This test is primarily used to detect fetal red blood cells in maternal circulation, which can occur during certain obstetric conditions, such as placental abruption or trauma, as well as during delivery.

When fetal red blood cells are present in maternal blood, they will resist acid elution during the staining process and can be visualized under a microscope, giving a positive result. This is particularly important in monitoring Rh sensitization, where the identification of fetal cells can help assess the extent of fetal-maternal hemorrhage, guiding further clinical decisions regarding management and treatment.

The other options do not accurately describe the purpose or outcome of the Kleihauer-Betke stain. It is not used to identify maternal cells, the Rh factor, or to indicate the success of fetal blood transfusions.