Management of patients expressing an altered form of the D antigen in combination with the R0 phenotype (D+ C- E-)

RCI practice is continually evolving to integrate developments in technology and knowledge. As a result of technological advances, the reporting of patients with anomalous D typing who express the C- E- phenotype was changed. This patient cohort is unlikely to be weak D type 1, 2 or 3. These weak D types do not make immune (allo) anti-D and should therefore be regarded as D variants due to the theoretical possibility of forming allo-anti-D. There remains insufficient data regarding the probability of D alloimmunisation in patients who express an altered form of D and are C- E-, but this group is considered a low clinical risk.

It has recently been identified that a number of cases, whilst reported as per the policy at the time of testing, would now be reported differently. Therefore RCI offer the following advice for the management of patients expressing an altered form of the D antigen in combination with the R₀ phenotype (D+ C- E-):

• Given the low probability of D alloimmunisation, a recall of patients for repeat testing is not deemed clinically necessary
• During routine testing, any cases previously reported by RCI as D+weak, C-, E- should be referred to RCI for retesting if possible
• Laboratories in receipt of conflicting reports (D+weak, C-, E- versus D variant, C-, E-) should regard patients as D variants (and therefore D negative) for transfusion and perinatal care
• There is no change in guidance for midwives. D+weak patients should not be administered anti-D prophylaxis
• The British Society for Haematology's guidelines for pre-transfusion compatibility procedures in blood transfusion laboratories should be followed if there is any doubt over a patient’s D status, with anomalous D results regarded as D negative until confirmed otherwise

We acknowledge the policy change was not communicated effectively and apologise for any confusion this may have caused.

Wisdom Musabaike - Assistant Director, Red Cell Immunohaematology