Which of the following criteria does not determine Rh immune globulin eligibility?

Rh immune globulin (RhIg) is administered to Rh-negative mothers to prevent Rh sensitization during pregnancy, especially if the infant is Rh-positive. The eligibility criteria for receiving Rh immune globulin include certain parameters about the mother and the infant's Rh status.

A mother being Rh-positive does not warrant the need for RhIg because if the mother is Rh-positive, she is already capable of producing the Rh factor and therefore does not require the immunoglobulin to prevent sensitization.

The infant being Rh-negative is also a crucial factor in determining eligibility; if the infant is Rh-negative, the risk of the mother becoming sensitized to the Rh factor is very low, thereby eliminating the need for RhIg.

The requirement that the mother has not been previously immunized to the D antigen is key as well because if she has been sensitized to Rh-positive blood in a prior pregnancy or blood transfusion, she may already have antibodies against the D antigen, imposing risk to future pregnancies.

In contrast, the presence of a positive direct antiglobulin test (DAT) is not suitable for RhIg eligibility. A positive DAT indicates that there are antibodies attached to the infant's red blood cells, potentially suggesting existing sensitization, which undermines the purpose