Before discussing crossmatch policies for women with passive anti-D likely due to RhIg, LIS-related issues will be outlined. A transfusion service's LIS and how it is configured determines under which circumstances an electronic crossmatch is possible.
Regardless of crossmatch policy, almost all laboratories use a special designation or code in their LIS for anti-D likely due to RhIg.
Often this designation is entered in the patient history comment field and not the antibody field, thus eliminating the need to remove the passive anti-D from the antibody field when the antibody disappears. Using this policy, once the passive antibody no longer reacts, the patient becomes eligible for an electronic crossmatch without the need to remove the antibody history.
In essence, using a special designation for passive anti-D allows the lab to bypass the LIS's normal requirements for patients with clinically significant antibodies, ie, allows them to omit doing an IAT crossmatch.
Examples of how RhIg-derived anti-D is designated in lab information systems:
- Passive anti-D (eg., code 'PD', 'DPAS', etc.);
- Probably passive anti-D;
- Anti-D consistent with RhIg;
- Anti-D due to RhIg.
Depending on the LIS, other variations are possible.