Use of cffDNA to avoid administration of anti‐D to pregnant women when the fetus is RhD‐negative: implementation in the NHS

Abstract

Objective To determine whether a policy of offering cffDNA testing to all RhD-negative women at about 16 weeks' gestation to avoid anti-D administration when the fetus is RhD-negative could be implemented successfully in the NHS without additional funding.Design Prospectively planned observational service implementation pilot and notes audit.Setting Three maternity services in the South West of England.Population All RhD-negative women in a 6-month period.Methods Prospective, intervention, cross-sectional observational study, using pre-intervention data as controls.Main outcome measures Proportion of suitable women who offered and accepted the test. Accuracy of the cffDNA result as assessed by cord blood group result. Fall in anti-D doses administered.Results 529 samples were received; three were unsuitable. The results were reported as RhD-positive (n = 278), RhD-negative (n = 185) or inconclusive, treat as positive (n = 63). Cord blood results were available in 502 (95%) and the only incorrect result was one case of a false positive (cffDNA reported as positive, cord blood negative -and so given anti-D unnecessarily). The notes audit showed that women who declined this service were correctly managed and that anti-D was not given when the fetus was predicted to be RhD-negative. The total use of anti-D doses fell by about 29% which equated to about 35% of RhD-negative women not receiving anti-D in their pregnancy unnecessarily.Conclusions We recommend this service is extended to all UK NHS services.

High-throughput non-invasive prenatal testing for fetal rhesus D status in RhD-negative women not known to be sensitised to the RhD antigen: a systematic review and economic evaluation

“…All the studies were prospective studies and were conducted in European countries. Four studies were conducted in England,12,[17][18][19] three of which were based in Bristol. 12,17,18 The sample size (number of patients/samples analysed) of studies ranged from 282 to 18,383 …”

“…We conducted sensitivity analyses (SAs) to explore: l the impact of including and excluding undetermined or uninterpretable NIPT results on the pooled test accuracy estimates l test accuracy in UK (Bristol)-based studies 12,17,18 only.…”

“…After initial screening of titles and abstracts, 227 were considered to be potentially relevant and were ordered for full-text paper screening. In total, eight studies 12,[17][18][19][20][21][22][23] were included in the diagnostic review of high-throughput NIPT, seven studies 18,20,22,[24][25][26][27] were included in the clinical effectiveness review and 12 studies 13,17,18,[20][21][22][23][24][25][26][27][28] were included in the review of implementation of high-throughput NIPT (with some overlap between studies). Figure 1 shows a flow diagram outlining the screening process with reasons for exclusion of full-text papers.…”

“…Although this was the policy in the three high-quality studies performed in Bristol, data on inconclusive tests were not reported in two studies. 21,22 Given these differences we considered four approaches to the diagnostic analysis: 12,17,18 This last analysis is likely to represent the most plausible results for UK practice, assuming that the methods used in Bristol are retained nationwide.…”

“…Estimates with 95% CI Finning 2008 17 Akolekar 2011 19 Wikman 2012 23 Grande 2013 22 Banch Clausen 2014 20 Chitty 2014 12 Soothill 2015 18 Thurik 2015 …”