A colleague in Michigan wonders if others will change their practice regarding RhIG administration during/after pregnancy once the 22nd edition of the AABB Standards becomes effective. He wonders if colleagues routinely perform antibody screening prior to antepartum RhIG therapy and at delivery. If not, how many colleagues will begin to do so, once the 22nd edition becomes effective; i.e., will colleagues find the subtle wording change in the Standard (see below) to be a more compelling reason to do such testing routinely? If the antibody screen is done and positive due to anti-D, how will colleagues differentiate between passive and native anti-D?

• Standard 5.18.4.1.2.1 (21st edition)
  All Rh-negative pregnant women shall be considered candidates for RhIG unless the fetus/infant is Rh-negative, or the woman is actively immunized to the D antigen.
  
  
• Standard 5.20.3 (22nd edition)
  Women who are pregnant or who recently have been pregnant shall be considered for RhIG administration when all of the following apply:

1. The woman's test for D antigen is negative (a test for weak D is not required).
2. The woman is not actively immunized to the D antigen.
3. The Rh type of the fetus or infant is unknown or the Rh type of the fetus is positive when tested for D or weak D (weak D testing is required when the test for D is negative).

The following responses have been received.

ADDENDA Nov. 3, 2003

1. A colleague in Australia reports that the issues raised about RhD immunoglobulin antenatal prophylaxis, testing and reporting are something practitioners and laboratory personnel in Australia are just beginning to address. He is of the opinion that in his country there is no way that a laboratory test can definitely discriminate between passive and native anti-D. He adds that at present, screening in RhD negative women will be at first antenatal visit, and again at 28 weeks just prior to RhD Ig administration. No further screening will be performed unless there are other factors indicating the need for further screening. The article by Judd WJ (Practice guidelines for prenatal and perinatal immunohaematology, revisited. Transfusion 2001;41:1445-1452) provides recommendations on this issue. The Australian colleague continues saying that the introduction of antenatal prophylaxis in Australia has necessitated a review of their national guidelines by ANZSBT . Updated dated guidelines will be published shortly. He also reports that with antenatal prophylaxis, they now see positive results from cord DAT testing in RhD Positive neonates whose mothers have received RhD Ig. This raises the question as to whether a cord DAT should be a 'routine test' or one that is requested only on clinical grounds, eg., neonatal hyperbilirubinemia.

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator