Objective: Severe combined immunodeficiency (SCID) is a rare, treatable disorder of the immune system. The incidence is unknown but may be more common than published estimates because infants frequently die of infection before diagnosis. SCID is a candidate for universal newborn screening, so there is a need to determine under which circumstances screening would be cost-effective.
Study design: We assumed a screening program for SCID would use T-cell lymphopenia as the screening criterion and performed a cost-utility analysis comparing universal screening with screening only those with a family history of SCID.
Results: Assuming society is willing to pay $50,000 for every quality-adjusted life-year saved, a SCID screening test that cost less than $5 with a false-negative rate of 0.9% and a false-positive rate of 0.4% would be considered cost-effective. A nationwide screening program would cost an additional $23.9 million per year for screening costs but would result in 760 years of life saved per year of screening. The cost to detect 1 case of SCID would be $485,000.
Conclusion: SCID screening could result in a large benefit to detected individuals, making screening relatively cost-effective in spite of the low incidence of the disease. However, an adequate test is critical to cost-effectiveness.