Abstract
Abstract 2064
Background:
Systematic newborn screening (NBS) for sickle cell anemia (SCA) is a practice limited almost entirely to developed countries, which include only a small fraction of annual global SCA births. There are several different laboratory methods used for NBS of hemoglobin disorders, including isoelectric focusing (IEF), capillary electrophoresis (CE), high-performance liquid chromatography (HPLC) and DNA-based testing. However, most NBS occurs in developed countries with standardized specimen collection and storage techniques, advanced laboratory technology and support, and adequate financial resources. For the newly instituted pilot newborn screening program in Angola, IEF and CE were initially selected as the laboratory methods of choice. After the first 12 months of the pilot program, we analyzed the costs of developing the NBS program and compared the reliability and consistency of newborn hemoglobin identification.
Methods:
After birth, two dried bloodspots (DBS) are collected by heelstick onto a Whatman screening card. Specimens are dried, placed in plastic bags for storage, and transported every 1–3 days to the central NBS laboratory at Hospital Pediátrico David Bernardino, where they are refrigerated until testing. All specimens are initially tested by IEF (RESOLVE neonatal hemoglobin system, PerkinElmer Inc.) within 3–5 days. Hemoglobin identification is performed using a fluorescent glow box and samples are scored according to the presence of HbF, HbA and HbS. The FAS pattern is consistent with sickle cell trait and FS is consistent with SCA. All IEF results with an FAS or FS pattern or an uncertain result are selected for repeat analysis by CE, performed using the CAPILLARYS 2 NEONAT FAST system (Sebia, Inc.). All newborns with an FS result by either method were contacted by telephone to obtain repeat sample for confirmatory testing and enrollment in the newborn sickle cell clinic.
Results:
Costs:
Initial start-up costs included 20,000 DBS cards designed specifically for the Angolan program ($45,000 USD) and lab equipment ($40,330 for IEF, $118,155 for CE, total of $158,485 USD), sufficient for the entire first year of the program. Collection costs (including gloves, lancets and alcohol pads) were calculated at $0.46 USD per sample, while sample collection and transport was $0.09 per sample. Once the DBS samples were received at the central testing laboratory, the reagent costs for sample analysis were $1.06 for IEF and $3.52 for CE, while labor costs were $0.35 for each test.
Laboratory Reliability:
To date, 17,055 samples have been run by IEF and 100% of these samples have obtained an adequate IEF result regardless of quality of bloodspot. To date, 2,895 samples have been selected for CE analysis, but only 2,031 (70.2%) produced interpretable results by CE. The remaining 29.8% of samples (mostly within the first 6 months of CE training period) did not produce a result due to hemoglobin degradation, inadequate blood spotting technique, mechanical failure, or unclear technical issues. For specimens with a result by both IEF and CE, concordance was greater than 99%.
Conclusions:
The development of a newborn screening program for SCA in Angola required an initial financial investment to obtain appropriate laboratory testing equipment. After this upfront investment, the total cost of newborn screening for SCA, including costs of collection, processing and laboratory analysis was about $3 USD for each initial IEF screening test and $4–5 USD for each CE result. This per-cost test compares favorably in relation to the public health benefit of identifying and retrieving affected infants. The cost of initiating a program in other countries may be significantly less than in Angola, which has a very expensive economy and resulted in high prices for many of the reagent and equipment costs. Given the variable quality of dried blood spot collection and the unavailability of ideal specimen storage and transport conditions, isoelectric focusing appears to be a more reliable, robust and economical method of newborn screening than capillary electrophoresis for sickle cell anemia in sub-Saharan Africa.
Disclosures:
No relevant conflicts of interest to declare.
Newborn Screening for Sickle Cell Disease and Other Hemoglobinopathies: A Short Review on Classical Laboratory Methods—Isoelectric Focusing, HPLC, and Capillary Electrophoresis
