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Introduction: People living with HIV (PLWH) have higher rates of non-infectious comorbid diseases (NCDs) than individuals without HIV. We characterized the risk of NCDs among PLWH with undetectable viral load and persistent low-level viraemia (pLLV) in the African Cohort Study (AFRICOS). We secondarily quantified the role of immune activation in the association between LLV and NCDs., Methods: AFRICOS enrols participants in 12 clinics in Uganda, Kenya, Tanzania and Nigeria. Participants on antiretroviral therapy ≥ 6 months without an NCD at enrolment were included. PLLV was defined as at least two consecutive visits with a detectable viral load <1000 copies/ml. We examined elevated blood pressure, hypercholesterolemia, hyperglycaemia, renal insufficiency and a composite variable of any NCD. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard modelling. Among a subset of participants with biomarker data, we assessed the interaction between viral load and 13 biomarkers in the association with any NCD., Results: From 23 January 2013 to 1 December 2022, 1755 participants met the inclusion criteria for these analyses. At the first eligible visit, the majority of participants had an undetectable viral load (n = 1375, 78.35%). Participants with pLLV had an increased rate of developing any NCD (aHR: 1.22, 95% CI: 1.02-1.47) compared to participants with an undetectable viral load. There was a statistically significant interaction between LLV and TNF-α, CCL2/MCP-1 and TNF-RII in the association with any NCD., Conclusions: PLLV was significantly associated with NCDs and immune inflammation in this population. Aggressive management of LLV may positively impact NCDs in PLWH., (© 2024 The Author(s). Journal of the International AIDS Society published by John Wiley & Sons Ltd on behalf of International AIDS Society.)

Background and Objectives: Parents and siblings of very low birth weight, premature infants are at risk for poor mental health outcomes with increased mental health care usage. Knowledge regarding mental health care use patterns could guide interventions., Methods: This retrospective cohort study included US families with commercial insurance coverage from a single carrier. Neonates born at ≤30 weeks' gestational age or with a birth weight <1500 g were identified by insurance claim data between July 1, 2015, and June 30, 2016. Each case neonate family was matched with up to 4 control families., Results: The study included 1209 case and 1884 control neonates (with 134 deaths among only the case neonates [11.1% of cases]); 2003 case and 3336 control parents (mean [SD] age, 34.6 [5.4] years; 2858 [53.5%] female); and 884 case and 1878 control siblings (mean [SD] age, 6.8 [5.5] years; 1375 [49.8%] female). Compared with controls, more case parents used mental health care over the first year after birth hospitalization discharge. Higher usage was observed for bereaved case parents soon after their child's death. A smaller proportion of bereaved case siblings received mental health care compared with controls. Although nonbereaved case parents returned toward the proportion of use observed in controls, nonbereaved case female siblings, bereaved case female and male siblings, and bereaved male parents experienced continued differences., Conclusions: Understanding and meeting the mental health care needs of parents and siblings of very low birth weight premature neonates can be guided by these findings, including elevated and prolonged needs of bereaved parents and siblings., (Copyright © 2024 by the American Academy of Pediatrics.)

Prenatal exposure to inflammation is related to the risk for cognitive impairment in offspring. However, mechanisms underlying the link between inflammatory cytokines at the maternal-fetal interface and human cognitive development are largely unknown. This study addressed this research gap by examining whether i) cytokines within the placenta are associated with different domains of neurocognitive development during infancy, and ii) if DHEA-S in cord blood mediates these associations. We also explored the role of early-life socioeconomic status (SES) in moderating the effect of fetal adrenal steroids on cognitive development in low- and middle-income country contexts. A cohort of 242 mother-infant dyads in Leyte, the Philippines participated in the study and all of them were followed from early pregnancy until 12-months. Concentrations of pro- and anti-inflammatory cytokines in the placenta, and DHEA-S in cord blood collected at delivery were evaluated. The multifactorial aspects of the infant's cognitive functioning were assessed based on the Bayley Scales of Infant Development, third edition (BSID-III). We used Structural Equation Modelling (SEM) with an orthogonal rotation to examine associated paths among latent variables of pro- and anti-inflammatory cytokines in the placenta, fetal neuroendocrine factors, and cognitive development. Pathway analyses showed that both pro- and anti-inflammatory cytokines in the placenta were indirectly related to cognitive (p < 0.05) and language developmental outcomes (p < 0.1) via DHEA-S in cord blood among the low SES group. Yet, we found no statistically significant indirect effect of pro- or anti-inflammatory cytokines on neurocognitive development among the high SES sub-sample. This study extends our understanding of how early-life socioeconomic conditions modify biological pathways underlying the relationship between prenatal factors and postpartum cognitive development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: Poor intrauterine growth has negative impacts for child growth and development and disproportionately affects children living in low-resource settings. In the present study, we investigated relationships between placental pathologies and indicators of poor intrauterine growth., Methods: We enrolled a longitudinal cohort of 279 mother-infant pairs from Leyte, the Philippines. Placental measures included characteristics, pathological findings, and immunohistochemistry. At birth, intrauterine growth was assessed using anthropometric measures, weight-for-gestational age, and the clinical assessment of nutritional status score (CANSCORE) for determining fetal malnutrition. Multivariate linear regression and log-binomial regression models were applied, controlling for potential confounding factors., Results: Maternal vascular malperfusion (MVM) was related to reduced birthweight (P < 0.0001), birth length (P = 0.002), head circumference (P = 0.001), and weight-to-length ratio (P = 0.016). MVM increased the risk for preterm delivery (P = 0.0005) and small for gestational age (SGA) (P = 0.016). Acute chorioamnionitis (P = 0.013) and MVM (P = 0.021) both led to an increased risk for fetal malnutrition defined by CANSORE<25. Villous tissue activated caspase-3 was associated with lower birth length (P = 0.0006), higher weight-to-length ratio (P = 0.004), reduced risks for SGA (P = 0.011) and low weight-to-length ratio for gestational age (P = 0.004)., Conclusion: The present study applied comprehensive measures for intrauterine growth and demonstrates that low placental weight and placental pathology, chiefly MVM, contribute to poor intrauterine growth. A better understanding of the mechanistic role of specific placental pathologies on adverse newborn outcomes will provide opportunities for reducing incidence of poor intrauterine growth and associated long-term morbidities., (© 2023 International Federation of Gynecology and Obstetrics.)

In a cross-sectional analysis of 354 Ugandan children (age 12-48 months) infected with Schistosoma mansoni, we assessed relationships between infection intensity and nutritional morbidities. Higher intensity was associated with an increased risk for anemia (RR = 1.05, 95% confidence interval [CI] 1.01-1.10) yet not associated with risk for underweight, stunting, or wasting., Competing Interests: Potential conflicts of interest. A. L. B. reports grants from UKRI Future Leaders Fellowship in Global Health (grant number MR/T041900/1) and Wellcome Trust Biomedical Facilities Grant (Schistosomiasis Snail Resource Facilities—SSR). S. C. reports receipt of the Thrasher Early Career Award. J. F. F. reports a Midcareer Investigator Award in Patient Oriented Research from US National Institutes of Health/NIAID (award number K24 AI112964-06). E. L. W. reports grants from UK Medical Research Council (MRC), UK National Institute for Health and Care Research (NIHR), and European and Developing Countries Clinical Trial Partnership—European Union (EDCTP). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Periportal fibrosis is a late-stage manifestation of chronic infection with Schistosoma mansoni . Praziquantel (PZQ), the only drug available for the treatment of schistosomiasis, has limited effect in treating established morbidity. Preschool-age children (PSAC) are not considered to be an at-risk population for severe morbidity. However, the prevalence of periportal fibrosis in PSAC in S. mansoni endemic settings is unknown., Methods: As part of a phase II clinical trial comparing different dosing regimens of PZQ in children age 12-47 months infected with S. mansoni in Uganda ("praziquantel in preschoolers" trial), we present baseline results assessing liver ultrasound (US) findings as per the WHO Niamey Protocol., Results: A total of 7/347 (2%) PSAC had Image Pattern C with pipe stems and echogenic rings suggestive of periportal fibrosis, 29/347 (8%) had Image Pattern B and 58 (17%) had evidence of periportal thickening There were higher adjusted odds of periportal thickening with older age [odds ratio (OR): 1.04; 95% confidence interval (CI): 1.00-1.07], primary maternal education (OR: 1.04; 95% CI: 1.00-1.07) and being taken to the lake weekly (OR: 3.02; 95% CI: 1.19-7.63). A further 44/347 children (13%) had a rounded caudal liver edge which was associated with high S. mansoni infection intensity (adjusted OR: 3.31; 95% CI: 1.46-7.51)., Conclusions: Incipient schistosomiasis-related liver morbidity was detected in young children enrolled in the praziquantel in preschoolers trial. Adequate age-adjusted reference measurements for liver ultrasound findings in very small children are lacking but urgently needed. Schistosomiasis-related fibrosis may be delayed or averted with early and repeated PZQ treatment., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Studies have implicated schistosomiasis as a cause of intestinal barrier disruption, a salient feature of environmental enteric dysfunction (EED), as eggs translocate from the sterile bloodstream through the gut wall. We examined the longitudinal impact of praziquantel (PZQ) treatment on a) EED biomarkers and b) Insulin growth factor I (IGF-1), a key driver of childhood linear growth, since EED has been implicated in linear growth stunting., Methodology: 290 children infected with S. mansoni in Brazil were treated with PZQ at baseline. EED biomarkers lipopolysaccharide (LPS) and intestinal fatty acid binding-protein (I-FABP) were measured, as well as IGF-1 at baseline, 6 and 12-months. Multivariate regression analysis was applied to assess associations between S. mansoni intensity and plasma biomarkers (LPS, I-FABP, and IGF-1), controlling for potential confounding variables., Principal Findings: At baseline, S. mansoni infection intensities were 27.2% light, 46.9% moderate, and 25.9% heavy. LPS concentrations were significantly reduced at the 12-month visit compared to baseline (p = 0.0002). No longitudinal changes were observed for I-FABP or IGF-1 in the 6- or 12-month periods following baseline treatment. After 6-months, I-FABP concentration was significantly higher in high vs low intensity (p = 0.0017). IGF-1 concentrations were significantly lower among children with high and moderate vs low intensity infections at each study visit., Conclusions/significance: We report that S. mansoni infection impacts LPS, I-FABP and IGF-1. These findings suggest a mechanistic role for EED in schistosomiasis-related morbidities, particularly linear growth., Competing Interests: The authors have declared that no competing interests exist.

Hookworm infection is associated with poor nutritional outcomes, anemia, and impaired cognitive performance. We examined the association between maternal hookworm infection and birth outcomes in a cohort of women in Leyte, Philippines. We observed poor intrauterine growth characteristics associated with maternal hookworm only among male offspring, with lower birth weight, head circumference, and placental surface area. Male neonates also had higher insulin-like growth factor 2 (IGF-2) and lower adiponectin in cord blood. These data intriguingly suggest nutritional impacts of maternal hookworm infection during pregnancy may be divergent based on sex of the offspring., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Vitamin A is necessary for an adequate immune response to infections. Infection also alters vitamin A biomarkers, which interferes with assessment of vitamin A deficiency and thus impairs clinical management. Here we apply multiple strategies to adjust vitamin A biomarkers for inflammation during acute infection and evaluate associations between adjusted vitamin A status and immunologic response markers., Methods: We measured biomarkers in pediatric patients presenting with acute febrile illness in Guayaquil, Ecuador at paired acute and convalescent visits. Four adjustment strategies were applied to retinol-binding protein (RBP) concentrations: Thurnham correction factor (TCF), BRINDA regression correction (BRC), CRP-only adjustment factor (CRP), and proof-of-concept for a proposed interleukin 6 regression model (IL-6 RM). Adjusted RBP concentrations were compared between visits using the paired Wilcoxon signed-rank test. Multivariate regression analysis was used to assess associations between adjusted vitamin A status and immunologic response markers., Results: A sample of 57 participants completed the acute visit 1, and 18 of these individuals completed the convalescent visit 2. The IL-6 RM was the only strategy resulting in adjusted RBP concentrations that were not significantly different between paired visits (p = 0.20). Following RBP adjustment, 0.0% of participants were classified as vitamin A deficient (RBP ≤ 0.70 μmol/L) and 14.0% were classified as vitamin A insufficient (RBP ≤ 1.05 μmol/L). Adjusted vitamin A insufficiency was associated with an increase in macrophage inflammatory protein 1-alpha (MIP-1α, p = 0.03) and a pro-inflammatory immune response profile (p = 0.03) during the acute visit., Conclusions: We introduce a strategy for adjusting vitamin A in the context of clinical illness based on IL-6 concentrations that will need to be validated in larger studies. Assessment of vitamin A during infection allows for further understanding of how vitamin A status modulates immunopathology and enables targeted strategies for vitamin A supplementation in the context of infection among children in settings with high burdens of undernutrition and infectious diseases., Competing Interests: Conflicts of interest The authors declare no conflict of interest related to this work. David Erickson and Saurabh Mehta hold equity in a startup commercializing point-of-care tests for nutritional status developed in their research laboratories. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results., (Copyright © 2021 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)

In areas endemic to schistosomiasis, fetal exposure to schistosome antigens prime the offspring before potential natural infection. Praziquantel (PZQ) treatment for Schistosoma japonicum infection in pregnant women has been demonstrated to be safe and effective. Our objectives were to evaluate whether maternal PZQ treatment modifies the process of in utero sensitization to schistosome antigens potentially impacting later risk of infection, as well as immune response to S. japonicum. We enrolled 295 children at age six, born to mothers with S. japonicum infection who participated in a randomized control trial of PZQ versus placebo given at 12-16 weeks gestation in Leyte, The Philippines. At enrollment, we assessed and treated current S. japonicum infection and measured serum cytokines. During a follow-up visit four weeks later, we assessed peripheral blood mononuclear cell (PBMC) cytokine production in response to soluble worm antigen preparation (SWAP) or soluble egg antigen (SEA). Associations between maternal treatment group and the child's S. japonicum infection status and immunologic responses were determined using multivariate linear regression analysis. PZQ treatment during pregnancy did not impact the prevalence (P = 0.12) or intensity (P = 0.59) of natural S. japonicum infection among children at age six. Among children with infection at enrollment (12.5%) there were no significant serum cytokine concentration differences between maternal treatment groups. Among children with infection at enrollment, IL-1 production by PBMCs stimulated with SEA was higher (P = 0.03) in the maternal PZQ group compared to placebo. Among children without infection, PBMCs stimulated with SEA produced greater IL-12 (P = 0.03) and with SWAP produced less IL-4 (P = 0.01) in the maternal PZQ group compared to placebo. Several cytokines produced by PBMCs in response to SWAP and SEA were significantly higher in children with S. japonicum infection irrespective of maternal treatment: IL-4, IL-5, IL-10, and IL-13. We report that maternal PZQ treatment for S. japonicum shifted the PBMC immune response to a more inflammatory signature but had no impact on their offspring's likelihood of infection or serum cytokines at age six, further supporting the safe use of PZQ in pregnant women. Trial Registration: ClinicalTrials.gov NCT00486863., Competing Interests: The authors have declared that no competing interests exist. Author Remigio M. Olveda was unable to confirm their authorship contributions. On their behalf, the corresponding author has reported their contributions to the best of their knowledge

Background: When we were unable to identify an electronic data capture (EDC) package that supported our requirements for clinical research in resource-limited regions, we set out to build our own reusable EDC framework. We needed to capture data when offline, synchronize data on demand, and enforce strict eligibility requirements and complex longitudinal protocols. Based on previous experience, the geographical areas in which we conduct our research often have unreliable, slow internet access that would make web-based EDC platforms impractical. We were unwilling to fall back on paper-based data capture as we wanted other benefits of EDC. Therefore, we decided to build our own reusable software platform. In this paper, we describe our customizable EDC framework and highlight how we have used it in our ongoing surveillance programs, clinic-based cross-sectional studies, and randomized controlled trials (RCTs) in various settings in India and Ecuador., Objective: This paper describes the creation of a mobile framework to support complex clinical research protocols in a variety of settings including clinical, surveillance, and RCTs., Methods: We developed ConnEDCt, a mobile EDC framework for iOS devices and personal computers, using Claris FileMaker software for electronic data capture and data storage., Results: ConnEDCt was tested in the field in our clinical, surveillance, and clinical trial research contexts in India and Ecuador and continuously refined for ease of use and optimization, including specific user roles; simultaneous synchronization across multiple locations; complex randomization schemes and informed consent processes; and collecting diverse types of data (laboratory, growth measurements, sociodemographic, health history, dietary recall and feeding practices, environmental exposures, and biological specimen collection)., Conclusions: ConnEDCt is customizable, with regulatory-compliant security, data synchronization, and other useful features for data collection in a variety of settings and study designs. Furthermore, ConnEDCt is user friendly and lowers the risks for errors in data entry because of real time error checking and protocol enforcement., (©Caleb J Ruth, Samantha Lee Huey, Jesse T Krisher, Amy Fothergill, Bryan M Gannon, Camille Elyse Jones, Elizabeth Centeno-Tablante, Laura S Hackl, Susannah Colt, Julia Leigh Finkelstein, Saurabh Mehta. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 13.08.2020.)

Background: In an oversaturated market of publicly available mobile apps for psychosocial self-care and stress management, health care providers, patients, and consumers interested in mental health-related apps may wonder which, if any, are efficacious. Readily available metrics for consumers include user popularity and media buzz rather than scientific evidence., Objective: This systematic review aimed to (1) examine the breadth of therapeutic contents and features of psychosocial wellness and stress management apps available to self-help seekers for public download and (2) determine which of these apps have original research support., Methods: First, we conducted a systematic review of publicly available apps on the iPhone App Store (Apple Inc) and Android Google Play (Google LLC) platforms using conventional self-help-seeking search terms related to wellness and stress. The results were limited to English-language apps available for free download. In total, 2 reviewers independently evaluated all apps and discussed the findings to reach 100% consensus regarding inclusion. Second, a literature review was conducted on the included apps to identify supporting studies with original data collection., Results: We screened 3287 apps and found 1009 psychosocial wellness and stress management apps. Content varied widely. The most common evidence-based strategy was mindfulness-meditation, followed by positive psychology and goal setting. Most apps were intended to be used as self-help interventions, with only 1.09% (11/1009) involving an electronic therapist and 1.88% (19/1009) designed as a supplement to in-person psychotherapy. Only 4.66% (47/1009) of apps targeted individuals with psychological disorders, and less than 1% of apps (6/1009, 0.59%) targeted individuals with other chronic illnesses. Approximately 2% (21/1009, 2.08%) were supported by original research publications, with a total of 25 efficacy studies and 10 feasibility studies. The Headspace mindfulness app had the most evidence, including 8 efficacy studies. Most other scientifically backed apps were supported by a single feasibility or efficacy study., Conclusions: Only 2.08% (21/1009) of publicly available psychosocial wellness and stress management mobile apps discoverable to self-help seekers have published, peer-reviewed evidence of feasibility and/or efficacy. Clinicians and investigators may use these findings to help patients and families navigate the volume of emerging digital health interventions for stress management and wellness., (©Nancy Lau, Alison O'Daffer, Susannah Colt, Joyce P Yi-Frazier, Tonya M Palermo, Elizabeth McCauley, Abby R Rosenberg. Originally published in JMIR mHealth and uHealth (http://mhealth.jmir.org), 22.05.2020.)

Background: Micronutrients are known to modulate host immunity, and there is limited literature on this association in the context of dengue virus infection (DENV)., Methods: Using a nested case-control design in a surveillance program, we measured the following: anthropometry; nutritional biomarkers including serum ferritin, soluble transferrin receptor, retinol-binding protein (RBP), 25-hydroxy vitamin D, folate, and vitamin B12; and a panel of immune response markers. We then compared these measures across 4 illness categories: healthy control, nonfebrile DENV, other febrile illness (OFI), and apparent DENV using multivariate polytomous logistic regression models., Results: Among 142 participants, serum ferritin (ng/mL) was associated with apparent DENV compared to healthy controls (odds ratio [OR], 2.66; confidence interval [CI], 1.53-4.62; P = .001), and RBP concentrations (µmol/L) were associated with apparent DENV (OR, 0.03; CI, 0.00-0.30; P = .003) and OFI (OR, 0.02; CI, 0.00-0.24; P = .003). In a subset of 71 participants, interleukin-15 levels (median fluorescent intensity) were positively associated with apparent DENV (OR, 1.09; CI, 1.03-1.14; P = .001) and negatively associated with nonfebrile DENV (OR, 0.89; CI, 0.80-0.99; P = .03) compared to healthy controls., Conclusions: After adjusting for the acute-phase response, serum ferritin and RBP concentrations were associated with apparent DENV and may represent biomarkers of clinical importance in the context of dengue illness., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

In this work, we demonstrate a rapid diagnostic platform with potential to transform clinical diagnosis of acute febrile illnesses in resource-limited settings. Acute febrile illnesses such as dengue and chikungunya, which pose high burdens of disease in tropical regions, share many nonspecific symptoms and are difficult to diagnose based on clinical history alone in the absence of accessible laboratory diagnostics. Through a unique color-mixing encoding and readout strategy, our platform enabled consistent and accurate multiplexed detection of dengue and chikungunya IgM/IgG antibodies in human clinical samples within 30 min. Our multiplex assay offers several advantages over conventional rapid diagnostic tests deployed in resource-limited settings, including a low sample volume requirement and the ability to concurrently detect four analytes. Our platform is a step toward multiplexed diagnostics that will be transformative for disease management in resource-limited settings by enabling informed treatment decisions through accessible evidence-based diagnosis.

Background: Zika virus (ZIKV) infection is an emerging mosquito-borne disease, which is associated with an increase in central nervous system malformations and newborn microcephaly cases. This review investigated evidence of breastfeeding transmission from ZIKV-infected mothers to their children and the presence of ZIKV infection in breastfeeding-related fluids., Methodology/principal Findings: We conducted a systematic review of observational studies, case studies, and surveillance reports involving breastfeeding women with ZIKV infection in several international databases. Data extraction and analysis were conducted following a PROSPERO-registered protocol. From 472 non-duplicate records, two case reports met criteria for inclusion. We reviewed three cases of ZIKV infection among lactating mothers near the time of delivery. Two of the three (2/3) associated newborns had evidence of ZIKV infection. ZIKV was detected in breast milk of all three mothers. Breast milk detection results were positive in all mothers (3/3) by RT-PCR, one was positive by culture (1/3), and none was tested for ZIKV-specific antibodies. Serum samples were ZIKV positive in all mothers (3/3), and sweat was not tested for ZIKV., Conclusions/significance: We describe three cases of ZIKV-infected breastfeeding mothers who were symptomatic within three days of delivery, and two cases with ZIKV-infected newborns. While ZIKV was detected in the breast milk of all three mothers, the data are not sufficient to conclude ZIKV transmission via breastfeeding. More evidence is needed to distinguish breastfeeding transmission from other perinatal transmission routes.

Vitamin B12 is necessary for formation of red blood cells, DNA synthesis, neural myelination, brain development, and growth. Vitamin B12 deficiency is often asymptomatic early in its course; however, once it manifests, particularly with neurological symptoms, reversal by dietary changes or supplementation becomes less effective. Access to easy, low cost, and personalized nutritional diagnostics could enable individuals to better understand their own deficiencies as well as track the effects of dietary changes. In this work, we present the NutriPhone, a mobile platform for the analysis of blood vitamin B12 levels in 15 minutes. The NutriPhone technology comprises of a smartphone accessory, an app, and a competitive-type lateral flow test strip that quantifies vitamin B12 levels. To achieve the detection of sub-nmol/L physiological levels of vitamin B12, our assay incorporates an innovative "spacer pad" for increasing the duration of the key competitive binding reaction and uses silver amplification of the initial signal. We demonstrate the efficacy of our NutriPhone system by quantifying physiologically relevant levels of vitamin B12 and performing human trials where it was used to accurately evaluate blood vitamin B12 status of 12 participants from just a drop (~40 μl) of finger prick blood.