OBJECTIVE: To estimate the potential economic benefit of reduced indirect antiglobulin screening for Rh(D)-negative pregnant women.
METHODS: A chart review of all Rh(D)-negative mothers delivering at the University of Washington from 2002 to 2012 was conducted to determine the rate of gestational seroconversion to anti-D antibodies before 28 weeks of gestation. A decision tree was constructed to estimate the economic effects of eliminating the indirect antiglobulin screen at 28 weeks of gestation and instead immunizing all Rh(D)-negative, anti-D antibody-negative women with anti-D immune globulin at that time. A theoretical cohort of 100,000 women was modeled. Probabilities and costs were derived from published literature, chart review, and expert opinion. Univariate sensitivity analyses followed by a Monte Carlo analysis examined assumptions and uncertainties in our model across entire distributions.
RESULTS: The seroconversion rate of development of anti-D antibodies before 28 weeks of gestation in the cohort analyzed was 0.099% (2/2,029 women). From a societal perspective, the expected cost savings from implementing the reduced indirect antiglobulin screening strategy, per 100,000 women, ranged from $6 to $7.7 million. The overall cost savings for implementing this strategy in the United States for 1 year ranged from $34.7 to $35.6 million. This strategy remained cost-beneficial when varying our parameters (eg, anti-D immune globulin, antibody test cost) to their logical extremes. The Monte Carlo analysis verified the cost savings of our strategy.
CONCLUSION: The updated seroconversion rate and our model suggest that eliminating the 28-week antibody screen would be cost-beneficial from a societal perspective while posing minimal potential harm to the recipients.