Performing an immediate spin or electronic crossmatch for women who have detectable passively acquired anti-D from antenatal RhIg administration

A Canadian colleague wonders how other institutions interpret what AABB Standards and/or other blood safety standards permit with regards to performing an immediate spin or electronic crossmatch for women who meet all other criteria for such testing, but who have detectable passively acquired anti-D from antenatal RhIg administration. For example, in the following scenario, what would others do: "An Rh negative female has received antenatal Rh immune globulin (RhIg) and at delivery has a positive antibody screen consistent with passive anti-D, and an Rh negative reagent cell mini-panel excludes other clinically significant antibodies. Bottom line, there is only anti-D detectable".

The inquiring colleague has read multiple resources, including threads on the e-network Forum and the AABB Standards, ed. 26, and polled Canadian colleagues about crossmatch practices regarding the above scenario. In her experience, crossmatch practices vary in the above hypothetical situation. Some institutions require use of a full serologic (IAT) crossmatch for as long as the anti-D is detectable. Others use an immediate spin crossmatch or electronic crossmatch with Rh negative RBC (D typing confirmed in-house), according to their routine policies for patients with no detectable clinically significant antibodies and no record of them. Furthermore, most institutions use a special designation or code in their Laboratory Information System (LIS) that the detected anti-D is assumed to be from RhIg, often putting it in the comment, not the antibody, field, depending on the LIS. The antibody is designated as "passive anti-D", "Probably passive anti-D", "Anti-D consistent with RhIg", or some variation thereof. The special designation allows the institution to bypass any LIS restrictions for the type of crossmatch possible now and facilitates using the electronic crossmatch once the anti-D disappears.

She concludes asking: "Do policies that allow an immediate spin or electronic crossmatch (assuming all other criteria are met) for patients with a probable passive anti-D from RhIg meet AABB and other blood safety standards?" Everyone she has discussed this with to-date thinks the practices are not contraindicated by AABB standards and would satisfy accreditation requirements for AABB and CAP.

The following comments have been received in response.

ADDENDA Dec. 16, 2010

1. A colleague in Virginia comments that her transfusion service laboratory reports RhIG acquired anti-D as "anti - D due to RhIG". Their policy is to crossmatch such a patient using an antiglobulin crossmatch. If the patient needs blood products they are worked up just like any other patient needing blood transfusion, to rule out all other clinically significant antibodies.

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