ABSTRACT
OBJECTIVES: The objectives of the article is to compare pregnancy-associated plasma protein A (PAPP-A) and free ß-subunit of human chorionic gonadotropin (ß-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. METHODS: Serum 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 ß-hCG concentrations from serum and DBS were measured with an AutoDELFIA® (PerkinElmer, PerkinElmer, Turku, Finland) automatic immunoassay. Correlation and Passing-Bablok regression analyses were performed to compare marker levels. RESULTS: High correlation (>0.9) was observed for PAPP-A and ß-hCG levels between various sampling techniques. The ß-hCG concentration was stable between DBS and serum, PAPP-A concentration consistently lower in DBS. CONCLUSION: Our findings suggest that ß-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.
Subject(s)
Aneuploidy , Chorionic Gonadotropin, beta Subunit, Human/blood , Dried Blood Spot Testing , Pregnancy-Associated Plasma Protein-A/metabolism , Adult , Chorionic Gonadotropin, beta Subunit, Human/analysis , Cohort Studies , Cross-Sectional Studies , Female , Ghana , Health Resources , Humans , Pregnancy , Pregnancy Trimester, First , Pregnancy Trimester, Second , Pregnancy-Associated Plasma Protein-A/analysis , Prenatal Diagnosis , Young AdultABSTRACT
OBJECTIVES: This is the first report on the results of a first-trimester combined-test screening programme in the Netherlands in a multi-centre routine clinical setting. METHODS: Between July 2002 and May 2004, blood samples were taken from subjects in 44 centres in the Netherlands and sent to our laboratory to assay for maternal serum concentrations of fbeta-hCG and PAPP-A. Fetal nuchal translucency (NT) was measured in the participating centres at a gestational age (GA) of 10-14 weeks. Results of those pregnancies for which a combined biochemical and NT risk was calculated were included in the epidemiological analysis of this study. RESULTS: A total of 4033 singleton pregnancies were included in the analysis. The median maternal age of the analysed group was 36.5 years. The distribution of GA was biphasic, with median GA of 10.3 and 12.1 weeks, respectively. The detection rate using the combined ultrasound and serum screening at a cut-off level of 1 in 250 was 71% (15/21), with a screen-positive rate of 4.7%. CONCLUSION: The results of this study show that the first-trimester combined test is suitable as a prenatal screening test in a multi-centre routine clinical setting in the Netherlands. Strict performance evaluation should identify weaknesses in the organisation that impair the performance of the test. Here, the performance of NT was especially identified as a candidate for improvement.
