Dried Blood Spots Research Articles

Self-collected or staff-collected dried blood spot specimens for HIV-1 viral load testing

Self-collected or staff-collected dried blood spot specimens for HIV-1 viral load testing

Prenatal exposure to genocide and subsequent adverse childhood events are associated with DNA methylation of SLC6A4, BDNF, and PRDM8 in early adulthood in Rwanda.

We investigated associations between prenatal genocidal trauma, including maternal rape, and postnatal adverse childhood experiences (ACEs) on DNA methylation of genes associated with the stress response. In a comparative cross-sectional study of 91 Rwandan young adults, categorized by prenatal exposure to genocide and maternal rape, genocide without rape, and unexposed controls, we analyzed DNA methylation from dried blood spots and assessed ACEs and depression and anxiety symptoms at age 24. Prenatal exposure to maternal rape was associated with DNA methylation changes in BDNF and SLC6A4, with the association in BDNF attenuated after including ACE exposure in the model. Genocide exposure without rape was associated with methylation changes in PRDM8 after adjusting for early adversity. Methylation in BDNF and SLC6A4 correlated with depression and anxiety symptoms. These findings underscore the impact of prenatal and postnatal trauma on DNA methylation and mental wellbeing, emphasizing the need for continued support for survivors in the decades after conflict.

A Modular Genetic Approach to Newborn Screening from Spinal Muscular Atrophy to Sickle Cell Disease—Results from Six Years of Genetic Newborn Screening

Background/Objectives: Genetic newborn screening (NBS) has already entered the phase of common practice in many countries. In Germany, spinal muscular atrophy (SMA), severe combined immunodeficiency (SCID) and sickle cell disease (SCD) are currently a mandatory part of NBS. Here, we describe the experience of six years of genetic NBS including the prevalence of those three diseases in Germany. Methods: Samples and nucleic acids were extracted from dried blood spot cards, commonly used for NBS. A qPCR assay was used to detect disease-causing variants for SMA and SCD, and the detection of T-cell receptor excision circles (TRECs) was performed for SCID screening. Results: The results of the NBS of over 1 million newborns for SMA, approximately 770,000 for SCID and over 410,000 for SCD are discussed in detail. In these newborns, we have identified 121 cases of SMA, 15 cases of SCID and syndrome-based immunodeficiencies and 77 cases of SCD or β-thalassemia. Conclusions: The flexibility of multiplex qPCR is assessed as an effective tool for incorporating different molecular genetic markers for screening. The processing of dried blood spot (DBS) filter cards for molecular genetic assays and the assays are described in detail; turn-around times and cost estimations are included to give an insight into the processes and discuss further options for optimization. The identified cases are in the range expected for the total number of screened newborns, but present a more exact view on the actual prevalences for Germany.

Smartcard: an integrated approach for contaminant monitoring, from field to laboratory.

Effective food safety monitoring requires a multi-step approach from farm to fork, involving different methods, ranging from convenient screening devices to sophisticated laboratory confirmatory testing. However, sample transportation to routine laboratories is time-consuming and expensive. Simplified on-site sampling followed by laboratory analysis offers a potential solution. Dried blood spot (DBS) cards ensure stability and ease of sample transportation and are used in clinical testing. However, the applicability of such an approach could be broader and include the storage of dried extract from more complex (solid) matrices. Therefore, a simplified approach is presented here, using DBS cards for on-site sampling and subsequent laboratory confirmation for food contaminants. To achieve this, an analytical tool (Smartcard) was designed using 3D-printing technology. As a proof of concept, the approach was applied to detect the pesticide fipronil, which is widely used in ornamental flower production to limit pests and on poultry farms. The Smartcard can securely store the sample extracts on a DBS card (dried extract spot (DExS) card), incorporate the lateral flow immunoassay (LFIA) and immediately provide an estimate of contamination levels. After simplified in-syringe extraction of the sample, the LFIA allows direct screening of fipronil (half maximum inhibitory concentration of 6.5µg/l with calibration standards), and the same sample extract can be directly applied to the DExS card for storage and transport to the laboratory, where analyte re-extraction and instrumental analysis is performed using ultra high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detecting fipronil down to 0.8µg/kg.

Prepared, Protected, EmPowered (P3): Primary Results of a Randomized Controlled Trial Using a Social Networking, Gamification, and Coaching App to Promote Pre-exposure Prophylaxis (PrEP) Adherence for Sexual and Gender Minority (SGM) Youth Living in the United States.

The population-level reductions in HIV incidence attributed to pre-exposure prophylaxis (PrEP) have not been fully realized among sexual, gender, and racial/ethnic minority youth. P3 (Prepared, Protected, emPowered) is a comprehensive mobile application (app) intervention developed to support PrEP adherence through gamification, medication tracking, and social engagement. A randomized controlled trial was conducted with 246 young men who have sex with men (YMSM) and young transgender women who have sex with men (YTWMSM) currently on or planning to begin PrEP. Participants were randomized in a 1:1:1 ratio to: standard of care (SOC), P3 app (P3), or P3 app plus in-app adherence coaching (P3+). Adherence was measured at 3- and 6- months post enrollment by emtricitabine-triphosphate (FTC-TP) and tenofovir-diphosphate (TFV-DP) levels in dried blood spots consistent with PrEP use > 4 days/week. The primary outcome was the difference in the proportion adherent comparing P3/P3+ to SOC. P3/P3+ was associated with a higher proportion adherent compared to SOC for both outcome measures. At 3 months, the estimated increase in the proportion adherent was 0.13 (95% CI: 0.00, 0.27, p: 0.05) and 0.12 (95% CI: -0.03, 0.26, p: 0.11) for TFV-DP and FTC-TP, respectively. Estimated adherence was higher, but not statistically different, in P3+ compared to P3, for both TFV-DP and FTC-TP. Receipt of P3 (P3 or P3+) is associated with an increase in PrEP adherence among YMSM and YTWSM at 3 months. Additional analyses to discern the role of app usage and sociodemographic and behavioral factors on intervention effects are warranted.

Metabolomic signatures associated with fetal growth restriction and small for gestational age: a systematic review.

The pathways involved in the pathophysiology of fetal growth restriction (FGR) and small for gestational age (SGA) are incompletely understood. We conduct a systematic review to identify metabolomic signatures in maternal and newborn tissues and body fluids samples associated with FGR/SGA. Here, we report that 825 non-duplicated metabolites were significantly altered across the 48 included studies using 10 different human biological samples, of which only 56 (17 amino acids, 12 acylcarnitines, 11 glycerophosphocholines, six fatty acids, two hydroxy acids, and eight other metabolites) were significantly and consistently up- or down-regulated in more than one study. Three amino acid metabolism-related pathways and one related with lipid metabolism are significantly associated with FGR and/or SGA: biosynthesis of unsaturated fatty acids in umbilical cord blood, and phenylalanine, tyrosine and tryptophan biosynthesis, valine, leucine and isoleucine biosynthesis, and phenylalanine metabolism in newborn dried blood spot. Significantly enriched metabolic pathways were not identified in the remaining biological samples. Whether these metabolites are in the causal pathways or are biomarkers of fetal nutritional deficiency needs to be explored in large, well-phenotyped cohorts.

Real-Life Diagnostic Accuracy and Clinical Utility of Hepatitis B Virus (HBV) Nucleic Acid Testing Using the GeneXpert Point-of-Care Test System from Fresh Plasma and Dry Blood Spot Samples in The Gambia

The GeneXpert HBV Viral Load test is a simplified tool to scale up screening and HBV monitoring in resource-limited settings, where HBV is endemic and where molecular techniques to quantify HBV DNA are expensive and scarce. However, the accuracy of field diagnostics compared to gold standard assays in HBV-endemic African countries has not been well understood. We aim to validate the diagnostic performance of the GeneXpert HBV Viral Load test in freshly collected and stored plasma and dried blood spot (DBS) samples to assess turn-around-time (TAT) for sample processing and treatment initiation, to map GeneXpert machines and to determine limitations to its use in The Gambia. Freshly collected paired plasma and DBS samples (n = 56) were analyzed by the GeneXpert test. Similarly, stored plasma and DBS samples (n = 306, n = 91) were analyzed using the GeneXpert HBV test, in-house qPCR and COBAS TaqMan Roche. The correlation between freshly collected plasma and DBS is r = 0.88 with a mean bias of −1.4. The GeneXpert HBV test had the highest quantifiable HBV DNA viremia of 81.4% (n = 249/306), and the lowest was detected by in-house qPCR at 37.9% (n = 116/306) for stored plasma samples. Bland–Altman plots show strong correlation between GeneXpert and COBAS TaqMan and between GeneXpert and in-house qPCR with a mean bias of +0.316 and −1.173 log10 IU/mL, respectively. However, paired stored plasma and DBS samples had a lower mean bias of 1.831 log10 IU/mL, which is almost significant (95% limits of agreement: 0.66–3.001). Patients (n = 3) were enrolled in the study within a TAT of 6 days. The GeneXpert HBV test displayed excellent diagnostic accuracy by detecting HBV viremia in less than 10 IU/mL.

What is the ideal thyroid-stimulating hormone (TSH) threshold value in congenital hypothyroidism screening? Twin study.

Congenital hypothyroidism is the most common preventable cause of intellectual disability. Therefore, the majority of developed countries have aimed to diagnose cases early through screening programs. In these screening programs, levels of thyroid-stimulating hormone (TSH) and free thyroxine are examined in dried blood spots taken between days 3 and 5 of life. While many countries accept TSH threshold value of 8 mU/L, there is still no consensus on the ideal TSH threshold value. As no twin studies on the TSH threshold value have been conducted previously, this study was planned. Eight pairs of twins were included in the study, with one of the twins having plasma TSH value ≥8 mU/L and the other <8 mU/L, measured between days 3 and 5 of life. The study aimed to investigate whether determining threshold TSH value of 8 mU/L would be beneficial by comparing somatic growth, mental development, and neuromotor development between twins. The age, gender, gestational weeks, birth weights, height, weight, and initial TSH values taken between days 3 and 5 of all cases were recorded. The patients' plasma Vitamin B12, folate, 25-OH Vitamin D, ferritin, and hemoglobin levels were measured. After that, they were evaluated by a child and adolescent psychiatry. Finally, the Denver Developmental Test was applied to the cases. There was no significant impairment in somatic growth, mental development, and neuromotor development in the long-term outcomes of cases with plasma TSH ≥ 8 mU/L compared to those with plasma TSH < 8 mU/L among the twins participating in our study.

Child health, nutrition and gut microbiota development during the first two years of life; study protocol of a prospective cohort study from the Khyber Pakhtunkhwa, Pakistan

Recent evidence suggests that the development of gut microbiota during infancy affects several metabolic, immune, and endocrine pathways in humans. An imbalance in gut microbiota diversity or function, also known as dysbiosis, not only affects early child growth and development, but is also linked with the development of chronic, non-communicable diseases in later life. The Child Health And Microbiome Development Study – Pakistan (CHAMP) study aimed to longitudinally assess gut microbiota development and associated factors (maternal, child, and demographic) during early childhood in populations residing in malnutrition-endemic communities in Pakistan. A prospective cohort of mother-infant pairs (n=70) will be recruited from District Swat, Pakistan, and followed for two years. Complete information about demographic characteristics, anti-natal and post-natal care, dietary intake, feeding practices, and child health will be collected at baseline and 3, 6, 12, 18, and 24 months. Anthropometric measurements (height, weight, mid-upper arm circumference, and head circumference), dry blood spots, and fecal samples were also collected. Ethical approval for the study was obtained from Khyber Medical University, Pakistan. The study is also registered on clincaltrial.gov (Ref no: NCT05793294). The study findings will help researchers understand gut microbiota development, associated factors, and their impact on longitudinal growth in infants during the first two years of life.

Emerging threat of artemisinin partial resistance markers (pfk13 mutations) in Plasmodium falciparum parasite populations in multiple geographical locations in high transmission regions of Uganda

BackgroundArtemisinin-based combination therapy (ACT) is currently recommended for treatment of uncomplicated malaria. However, the emergence and spread of partial artemisinin resistance threatens their effectiveness for malaria treatment in sub-Saharan Africa where the burden of malaria is highest. Early detection and reporting of validated molecular markers (pfk13 mutations) in Plasmodium falciparum is useful for tracking the emergence and spread of partial artemisinin resistance to inform containment efforts.MethodsGenomic surveillance was conducted at 50 surveillance sites across four regions of Uganda in Karamoja, Lango, Acholi and West Nile from June 2021 to August 2023. Symptomatic malaria suspected patients were recruited and screened for presence of parasites. In addition, dried blood spots (DBS) were collected for parasite genomic analysis with PCR and sequencing. Out of 563 available dried blood spots (DBS), a random subset of 240 P. falciparum mono-infections, confirmed by a multiplex PCR were selected and used for detecting the pfk13 mutations by Sanger sequencing using Big Dye Terminator method. Regional variations in the proportions of pfk13 mutations were assessed using the chi square or Fisher’s exact tests while Kruskal–Wallis test was used to compare absolute parasite DNA levels between wild type and mutant parasites.ResultsOverall, 238/240 samples (99.2%) contained sufficient DNA and were successfully sequenced. Three mutations were identified within the sequenced samples; pfk13 C469Y in 32/238 (13.5%) samples, pfk13 A675V in 14/238 (5.9%) and pfk13 S522C in (1/238 (0.42%) samples across the four surveyed regions. The prevalence of pfk13 C469Y mutation was significantly higher in Karamoja region (23.3%) compared to other regions, P = 0.007. The majority of parasite isolates circulating in West Nile are of wild type (98.3), P = 0.002. Relative parasite DNA quantity did not differ in samples carrying the wild type, C469Y and A675V alleles (Kruskal–Wallis test, P = 0.6373).ConclusionDetection of validated molecular markers of artemisinin partial resistance in multiple geographical locations in this setting provides additional evidence of emerging threat of artemisinin partial resistance in Uganda. In view of these findings, periodic genomic surveillance is recommended to detect and monitor levels of pfk13 mutations in other regions in parallel with TES to assess potential implication on delayed parasite clearance and associated treatment failure in this setting. Future studies should consider identification of potential drivers of artemisinin partial resistance in the different malaria transmission settings in Uganda.

Comprehensive newborn screening for severe combined immunodeficiency, X-linked agammaglobulinemia, and spinal muscular atrophy: the Chinese experience.

Newborn screening (NBS) for severe combined immunodeficiency (SCID), X-linked agammaglobulinemia (XLA), and spinal muscular atrophy (SMA) enables early diagnosis and intervention, significantly improving patient outcomes. Advances in real-time polymerase chain reaction (PCR) technology have been instrumental in facilitating their inclusion in NBS programs. We employed multiplex real-time PCR to simultaneously detect T-cell receptor excision circles (TRECs), kappa-deleting recombination excision circles (KRECs), and the absence of the survival motor neuron (SMN) 1 gene in dried blood spots from 103,240 newborns in Zhejiang Province, China, between July 2021 and December 2022. Of all the samples, 122 were requested further evaluation. After flow cytometry evaluation and/or genetic diagnostics, we identified one patient with SCID, two patients with XLA, nine patients with SMA [one of whom also had Wiskott-Aldrich Syndrome (WAS)], and eight patients with other medical conditions. The positive predictive values (PPVs) of NBS for SCID, XLA, and SMA were 2.44%, 2.78%, and 100%, respectively. The estimated prevalence rates in the Chinese population were 1 in 103,240 for SCID, 1 in 51,620 for XLA, and 1 in 11,471 for SMA. This study represents the first large-scale screening in mainland China using a TREC/KREC/SMN1 multiplex assay, providing valuable epidemiological data. Our findings suggest that this multiplex assay is an effective screening method for SCID, XLA, and SMA, potentially supporting the universal implementation of NBS programs across China.

Unlocking the potential of dried blood spot sampling for SARS-CoV-2 antibody detection: A pathway to efficient pandemic surveillance

SummaryThe current SARS-CoV-2 pandemic has exerted unprecedented pressure on global healthcare systems, with an urgent demand for widespread testing to monitor virus spread and contribute to disease control. AimThis study aimed to validate the use of Dried Blood Spot (DBS) sampling for analyzing the immune response to SARS-CoV-2 infection, employing an accessible enzyme-linked immunosorbent assay (ELISA) for detecting IgG antibodies. MethodologyTraditional venous blood sampling presents several challenges, including discomfort to patients, risk of healthcare provider exposure, and the need for specialized equipment, which can limit mass testing capabilities. Our research involved the comparison of DBS and venous blood samples from 170 individuals, all of whom had PCR-confirmed SARS-CoV-2 infection, to assess the efficacy of DBS for seroprevalence studies and vaccine response evaluation. ResultsOur results confirmed that DBS sampling could detect SARS-CoV-2 IgG antibodies with 100 % accuracy, showcasing perfect agreement (Cohen's k value of 1.00) between DBS and venous serum samples in detecting the viral antibodies. However, the analysis indicated no significant correlation between the antibody levels in the two sampling methods. ConclusionThese results suggest that DBS is a viable, rapid alternative for serological studies, offering a solution to current testing limitations and enhancing our public health approach to combating future pandemics.

Wilson disease: Novel Diagnostic and Therapeutic Approaches.

The Wilson disease (WD) research field is rapidly evolving, and new diagnostic and therapeutical approaches are expected to be change-gamers in the disease for the incoming years, after decades of slow changing options. Non-ceruloplasmin bound copper assays for circulating bioavailable copper are being tested for use in monitoring therapy and may also help in the diagnosis of new cases of WD. Other diagnostic advances include use of quantitative detection of ATP7B peptides in dried blood spots, a method that is being tested for use in newborn screening for WD, and the use of metallothionein immuno-staining of liver biopsy specimens to differentiate WD from other liver diseases. Ongoing and future trials of gene therapy and use of methanobactin are expected to restore biliary copper excretion from the liver, thus making a cure for WD a plausible therapeutic objective. With the aim of helping updating physicians, this review summarizes the novel methods for WD diagnosis and future therapies. Advancing understanding of the scientific advances that can be applied to WD will be critical for ensuring that our patients will receive the best current and future care.

Neurodevelopment in the First 2 Years of Life Following Prenatal Exposure to Maternal SARS-CoV-2 Infection

The effects of prenatal exposure to SARS-CoV-2 infection on child development throughout the first 2 years of life are unknown. To evaluate whether prenatal exposure to SARS-CoV-2 infection was associated with child neurodevelopmental outcomes during the first 2 years of life. This cohort study used data from the longitudinal, population-based pan-Canadian Pregnancy During the COVID-19 Pandemic cohort, which recruited participants from April 2020 to July 2022. Children were categorized as exposed to prenatal SARS-CoV-2 infection if their birthing parent had a positive polymerase chain reaction test performed by a health authority or as a healthy negative comparison if their birthing parent did not have SARS-CoV-2 antibodies in their postpartum dried blood spot sample. Prenatal SARS-CoV-2 infection. The birthing parent reported on their child's temperament at ages 6 and 24 months, developmental milestones at ages 12 and 24 months, and social-emotional milestones at ages 12 and 24 months. A total of 896 children were included, with 96 children who had been exposed to a prenatal SARS-CoV-2 infection (mean [SD] gestational age at birth, 39.20 [1.50] weeks; 45 [47%] male) and 800 were healthy negative comparisons (mean [SD] gestational age at birth, 39.47 [1.54] weeks; 388 [49%] male). In analyses of covariance adjusted for prepregnancy medical conditions and household socioeconomic status, prenatal exposure to SARS CoV-2 infection was associated with slightly higher regulatory control scores, indicating more regulation, at age 6 months (difference in means, 0.19 [95% CI, 0.02-0.36]; P = .03; ηp2 = 0.01). No significant differences were observed for the other neurodevelopmental outcomes. In mixed models adjusted for the same covariates that aimed to examine change in outcomes over time, prenatal SARS-CoV-2 infection exposure was not associated with developmental change in any neurodevelopmental outcomes between ages 6 and 24 months. In this longitudinal cohort study of multiple aspects of child neurodevelopment between ages 6 and 24 months, negligible associations between prenatal exposure to SARS-CoV-2 infection and child outcomes were observed. Follow-up research is warranted to determine whether these predominantly null effects persist into later childhood.

GC-MS uncovers unique metabolic markers of drug-resistant epilepsy in capillary but not venous dried blood spots

This study compared the effectiveness of capillary dried blood spots (DBS) versus venous DBS in detecting metabolic changes related to drug-resistant epilepsy (DRE). DBS samples were collected from 142 epilepsy patients (58 drug-resistant, 84 drug-responsive) via venipuncture or fingerstick capillary sampling. Metabolomic analysis using gas chromatography-mass spectrometry compared DBS metabolite profiles between the two groups. While venous DBS profiles showed no distinct patterns, capillary DBS profiles revealed clustering patterns in principal components analysis, with the first two principal components explaining 14.5%, and 13.5% of the total variance, respectively. Orthogonal PLS-DA confirmed group discrimination (R2Y=0.989, Q2=0.742). Drug-resistant patients exhibited elevated capillary DBS levels of glutamine, pyruvic acid, and serine, and decreased palmitic acid compared to drug-responsive patients. Pathway analysis revealed disruptions in amino acid metabolism, neurotransmission, and cellular energy regulation. Elevated glutamine levels may contribute to an imbalance between excitatory glutamate and inhibitory GABA neurotransmission, key factors in epileptogenesis and drug resistance. Capillary DBS, likely enriched with arterial blood supply to the brain, appears to better capture central nervous system metabolic disturbances compared to venous DBS containing systemic contributions. This minimally invasive capillary DBS approach offers effective metabolic profiling of brain conditions like DRE, for monitoring disease progression and treatment response, enhancing personalized patient management in epilepsy.

Utilization and validation of dried blood spot-based metabolomics in plasma-derived diagnostic models

Metabolomics has rapidly advanced in life sciences, enhancing our understanding of physiological conditions. Plasma stands out as a predominant sample type in metabolomics studies. Dried blood spot (DBS) has been recognized as a valuable strategy due to its unique characteristics, such as minimal invasiveness, small sample volume, and easy transport. Most large cohort studies construct the diagnostic model using plasma-based metabolomics rather than DBS. However, the comparability of metabolite measurements between DBS and plasma samples, as well as the integration of DBS-based metabolomics into established plasma-derived diagnostic models, remains unclear. We collected plasma and DBS samples from the same 12 healthy controls under fasting and non-fasting conditions and performed ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS)-based metabolomics. We identified 277 metabolites present in both plasma and DBS samples, with 229 (82.7 %) showing a strong correlation between the two sample types. Furthermore, pre-processing datasets from plasma and DBS samples before combining them effectively diminished inconsistencies between plasma- and DBS-based metabolomics without compromising the inherent classification within the data. For the clinical application, the plasma samples were obtained from the gastric cancer patients (n = 204) and the healthy controls (n = 128) to serve as the training cohorts. Additionally, DBS samples were collected from different participants of gastric cancer (n = 19) and healthy controls (n = 12) to validate the diagnostic model. Finally, DBS-based metabolomics were integrated into established plasma-derived gastric cancer diagnostic models, yielding an area under the ROC curve (AUC) of 0.934. Overall, incorporating DBS-based metabolomics into an established plasma-derived diagnostic model holds promise, offering valuable opportunities and insights for diagnostic research and clinical practice.

Development of an enzyme-linked immunosorbent assay for newborns dried blood spot thyroglobulin.

Thyroglobulin (Tg) is a biomarker of iodine status. Newborn Tg is a more sensitive marker than neonatal TSH in detecting variations in iodine intake. This study aims to validate a Tg enzyme-linked immunosorbent assay (ELISA) for Tg determination on dried blood spots (DBS) in newborns. This study also set out to assess the stability of Tg and the influence of newborns' hematocrit on Tg determination. A commercially available ELISA Tg assay was adapted for use on DBS. DBS-Tg in cord blood were measured in 209 newborns delivered from healthy euthyroid pregnant women. Sensitivity, linearity, repeatability, and intermediate fidelity were determined using the appropriate standards and quality control materials. The limit of detection (LoD) of the DBS-Tg assay was 2.4 µg/L, and the limit of quantification (LoQ) was 5.8 µg/L. Repeatability and intermediate fidelity were 7.7-8.3% and 11.0-11.2%, respectively. The median cord plasma Tg and DBS-Tg values in newborns were not significantly different, 30.2 (21.3-44.4) µg/L and 31.6 (19.3-48.7) µg/L (p=0.48) with the ELISA respectively, and 76.5 (40.0-101.5) µg/L with the Elecsys assay with an R=0.88. DBS-Tg concentrations decrease with increasing hematocrit values (p<0.05). DBS-Tg values were stable at a concentration of 25 µg/L for 12 months at -20ºC and 4ºC. This DBS-Tg assay demonstrated good analytical performances over a wide range of Tg concentrations, suggesting it is well suited to detecting variations in Tg concentrations. Studies comparing populations with different prevalence of anemia should consider the effect of hematocrit on DBS-Tg determination. The availability of a DBS-Tg assay for newborns makes it possible to integrate iodine status monitoring with newborn screening for inherited metabolic diseases.

A Prospective Analysis of Per- and Polyfluoroalkyl Substances from Early Pregnancy to Delivery in the Atlanta African American Maternal-Child Cohort.

Longitudinal trends in per- and polyfluoroalkyl substances (PFAS) serum concentrations across pregnancy have not been thoroughly examined, despite evidence linking prenatal PFAS exposures with adverse birth outcomes. We sought to characterize longitudinal PFAS concentrations across pregnancy and to examine the maternal-fetal transfer ratio among participants in a study of risk and protective factors for adverse birth outcomes among African Americans. In the Atlanta African American Maternal-Child cohort (2014-2020), we quantified serum concentrations of four PFAS in 376 participants and an additional eight PFAS in a subset of 301 participants during early (8-14 weeks gestation) and late pregnancy (24-30 weeks gestation). Among these, PFAS concentrations were also measured among 199 newborns with available dried blood spot (DBS) samples. We characterized the patterns, variability, and associations in PFAS concentrations at different time points across pregnancy using intraclass correlation coefficients (ICCs), maternal-newborn pairs transfer ratios, linear mixed effect models, and multivariable linear regression, adjusting for socioeconomic and prenatal predictors. Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected in of maternal samples, with PFHxS and PFOS having the highest median concentrations. We observed high variability in PFAS concentrations across pregnancy time points (). All median PFAS concentrations increased from early to late pregnancy, except for PFOA and N-methyl perfluorooctane sulfonamido acetic acid (NMFOSAA), which decreased [paired -test for all PFAS except for PFOA and perfluorobutane sulfonic acid (PFBS)]. Prenatal serum PFAS were weakly to moderately correlated with newborn DBS PFAS ( ). The median maternal-fetal PFAS transfer ratio was lower for PFAS with longer carbon chains. After adjusting for socioeconomic and prenatal predictors, in linear mixed effect models, the adjusted mean PFAS concentrations significantly increased during pregnancy, except for PFOA. In multivariable linear regression, PFAS concentrations in early pregnancy significantly predicted the PFAS concentrations in late pregnancy and in newborns. We found that the concentrations of most PFAS increased during pregnancy, and the magnitude of variability differed by individual PFAS. Future studies are needed to understand the influence of within-person PFAS variability during and after pregnancy on birth outcomes. https://doi.org/10.1289/EHP14334.

Acceptability, barriers and facilitators of using dried blood spots-point-of-care testing for sickle cell disease in Africa: an implementation science protocol for a multinational qualitative study

BackgroundSickle cell disease (SCD) is a prevalent inherited blood disorder. Globally, approximately 515 000 babies are born with SCD annually, with 75% of these births occurring in Africa. Integrating newborn...

Nucleic Acid Amplification Testing using Dried Blood Spots to Confirm the Diagnosis of HIV-1 in Adults

Nucleic Acid Amplification Testing using Dried Blood Spots to Confirm the Diagnosis of HIV-1 in Adults