Dried blood spot measurement of pregnancy-associated plasma protein A (PAPP-A) and free beta-subunit of human chorionic gonadotropin (beta-hCG) from a low-resource setting

Abstract

ObjectivesThe objectives of the article is to compare pregnancy-associated plasma protein A (PAPP-A) and free -subunit of human chorionic gonadotropin (-hCG) concentrations in dried blood spots (DBSs) with serum of samples obtained from a public hospital in a low-resource setting and to evaluate their stability. MethodsSerum and DBS samples were obtained by venipuncture and finger prick from 50 pregnant participants in a cohort study in a public hospital in Accra, Ghana. PAPP-A and -hCG concentrations from serum and DBS were measured with an AutoDELFIA (R) (PerkinElmer, PerkinElmer, Turku, Finland) automatic immunoassay. Correlation and Passing-Bablok regression analyses were performed to compare marker levels. ResultsHigh correlation (>0.9) was observed for PAPP-A and -hCG levels between various sampling techniques. The -hCG concentration was stable between DBS and serum, PAPP-A concentration consistently lower in DBS. ConclusionOur findings suggest that -hCG can be reliably collected from DBS in low-resource tropical settings. The exact conditions of the clinical workflow necessary for reliable PAPP-A measurement in these settings need to be further developed in the future. These findings could have implications for prenatal screening programs feasibility in low-income and middle-income countries, as DBS provides an alternative minimally invasive sampling method, with advantages in sampling technique, stability, logistics, and potential application in low-resource settings. (c) 2015 John Wiley & Sons, Ltd.