IMPORTANT MESSAGE
Red Cell Antibody Screening in the context of the Rh (D) Antenatal Prophylaxis Program
Current Australian guidelines recommend that all Rh (D) negative women should have red cell antibody screening performed at their initial antenatal visit and at least once between 28 and 36 weeks gestation. In the context of routine antenatal prophylaxis, collection of a blood sample for antibody screening should be undertaken prior to the administration of the 28 week dose of Rh (D) immunoglobulin.
Two recent Australian cases of significant adverse fetal outcomes have highlighted the importance of clinicians ensuring the correct timing and interpretation of red cell antibody screening in the context of the Rh (D) antenatal prophylaxis program.
These two cases have reportedly been attributed to a lack of clarity as to whether the presence of Rh (D) antibodies was due to active alloimmunisation or prophylaxis. In both cases, the Rh (D) immunoglobulin was given prior to blood sample collection thus further complicating laboratory findings.
Similar experiences have also been reported in the 2005 UK Serious Hazards of Transfusion (SHOT) Annual Report which highlighted an increasing number of reports relating to Rh (D) immunoglobulin. In 2005, two cases were reported in which misinterpretation of the antenatal antibody investigation resulted in severe haemolytic disease of the fetus. The report recommended that implementation of routine Rh (D) antenatal prophylaxis must be supported by education.
In light of these reported cases, the Australian and New Zealand Society of Blood Transfusion is currently reviewing its guidelines for antenatal red cell antibody testing. This is being undertaken in conjunction with a Joint Rh (D) Consultative Committee (JCC) comprising of representatives from all key stakeholders including:
- Royal Australian and New Zealand College of Obstetrics and Gynaecology (RANZCOG)
- Royal Australian College of General Practitioners (RACGP)
- Australian College of Midwives Inc (ACMI)
- Australian and New Zealand Society of Blood Transfusion (ANZSBT)
- Australian Red Cross Blood Service (ARCBS)
- Royal College of Pathologists of Australasia (RCPA)
- CSL Limited
The results of this review will be communicated in the near future.
In the meantime, the JCC recommends that:
- When antenatal red cell antibody testing is indicated e.g. at 28 weeks gestation, the blood sample for the test should be collected prior to the administration of Rh (D) immunoglobulin. If Rh (D) immunoglobulin has already been administered, the test should still be performed and the prior administration of Rh (D) immunoglobulin should be highlighted on the laboratory request form.
- When a laboratory detects an Rh (D) antibody with a strong agglutination, even after the administration of Rh (D) immunoglobulin, quantification of the Rh (D) antibody should be performed.
Current information, which is likely to be updated, regarding Rh (D) immunoglobulin, the Rh (D)antenatal prophylaxis program or antenatal red cell antibody screening can be found by visiting the following websites: