Diagnostic Accuracy of the HemoCue Hb 301, STAT-Site MHgb and URIT-12 Point-of-Care Hemoglobin Meters in a Central Laboratory and a Community Based Clinic in Durban, South Africa

Urinary Ferritin as a Noninvasive Means of Assessing Iron Status in Young Children

BACKGROUND

Iron deficiency (ID) is the most common nutritional deficiency affecting young children. Serum ferritin concentration is the preferred biomarker for measuring iron status because it reflects iron stores; however, blood collection can be distressing for young children and can be logistically difficult. A noninvasive means to measure iron status would be attractive to either diagnose or screen for ID in young children.

OBJECTIVES

This study aimed to determine the correlation between urinary and serum ferritin concentrations in young children; to determine whether correcting urinary ferritin for creatinine and specific gravity improves the correlation; and to determine a urine ferritin cut point to predict ID.

METHODS

Validation study was conducted using paired serum and urine collected from 3-y-old children (n = 142) participating in a longitudinal birth cohort study: the ORIGINS project in Perth, Western Australia. We calculated the sensitivity, specificity, positive, and negative predictive values of urinary ferritin amount in identifying those with ID at the clinical cut point used by the World Health Organization (serum ferritin concentration of <12 ng/mL).

RESULTS

Urine ferritin, corrected for creatinine, correlated moderately with serum ferritin [r = 0.53 (0.40-0.64)] and performed well in predicting those with ID (area under the curve: 0.85; 95% confidence interval: 0.75, 0.94). Urine ferritin <2.28 ng/mg creatinine was sensitive (86%) and specific (77%) in predicting ID and had a high negative predictive value of 97%; however, the positive predictive value was low (40%) owing to the low prevalence of ID in the sample (16%).

CONCLUSIONS

Urine ferritin shows good diagnostic performance for ID. This noninvasive biomarker maybe a useful screening tool to exclude ID in healthy young children; however, further research is needed in other populations.

Hemoglobin measurement in venous blood compared with pooled and single-drop capillary blood: a method-comparison study in a controlled and survey setting in Uganda among children and women

BACKGROUND

Standard practice for estimating anemia in population-based surveys is to use a point-of-care device to measure hemoglobin (Hb) in a single drop of capillary blood. Emerging evidence points to larger than expected differences in Hb concentration depending on the blood source.

OBJECTIVE

We evaluated use of different blood sources to measure Hb with a HemoCue 201+ analyzer compared with the reference method of venous blood tested with a Sysmex XN-450 hematology analyzer.

METHODS

Hb concentration in venous, pooled capillary, and single-drop capillary blood were collected in controlled (laboratory) and survey (Demographic Health Survey-8 pilot) settings in Uganda among children 6-59 mo and nonpregnant women 15-49 y. Venous and capillary blood collected from the same individual was tested using a HemoCue 201+ analyzer and the venous blood was also measured with a Sysmex XN-450 hematology analyzer. Agreement between measures was estimated using Lin's concordance correlation coefficient, Bland-Altman plots, and Deming regression. Means and prevalences were compared using paired t-tests and McNemar's tests, respectively.

RESULTS

The limits of agreement between Hb measured using a HemoCue 201+ analyzer and the reference method were lowest for venous (1.1-1.96 g/dL), followed by pooled capillary (1.45-2.27 g/dL), and single-drop capillary blood (2.23-3.41 g/dL). Mean differences were <0.5 g/dL across comparators. There were statistically significant differences in Hb concentration from both types of capillary blood. Anemia prevalence was lower in pooled capillary blood compared with the reference method.

CONCLUSIONS

The variability of Hb measured by capillary blood using the HemoCue 201+ analyzer is higher than venous blood but the extent to which this impacts the validity of Hb and anemia estimates requires further exploration. Future research is also needed to evaluate the implications of using venous compared with capillary blood in population-based surveys. This trial was registered at clinicaltrials.gov (NCT05059457).

Use of point-of-care haemoglobin tests to diagnose childhood anaemia in low- and middle-income countries: A systematic review

OBJECTIVES

Anaemia is a major cause of mortality and transfusion in children in low- and middle-income countries (LMICs); however, current diagnostics are slow, costly and frequently unavailable. Point-of-care haemoglobin tests (POC(Hb)Ts) could improve patient outcomes and use of resources by providing rapid and affordable results. We systematically reviewed the literature to investigate what, where and how POC(Hb)Ts are being used by health facilities in LMICs to diagnose childhood anaemia, and to explore challenges to their use.

METHODS

We searched a total of nine databases and trial registries up to 10 June 2022 using the concepts: anaemia, POC(Hb)T, LMIC and clinical setting. Adults ≥21 years and literature published >15 years ago were excluded. A single reviewer conducted screening, data extraction and quality assessment (of diagnostic studies) using QUADAS-2. Outcomes including POC(Hb)T used, location, setting, challenges and diagnostic accuracy were synthesised.

RESULTS

Of 626 records screened, 41 studies were included. Evidence is available on the use of 15 POC(Hb)Ts in hospitals (n = 28, 68%), health centres (n = 9, 22%) and clinics/units (n = 10, 24%) across 16 LMICs. HemoCue (HemoCue AB, Ängelholm, Sweden) was the most used test (n = 31, 76%). Key challenges reported were overestimation of haemoglobin concentration, clinically unacceptable limits of agreement, errors/difficulty in sampling, environmental factors, cost, inter-observer variability and supply of consumables. Five POC(Hb)Ts (33%) could not detect haemoglobin levels below 4.5 g/dL. Diagnostic accuracy varied, with sensitivity and specificity to detect anaemia ranging from 24.2% to 92.2% and 70% to 96.7%, respectively.

CONCLUSIONS

POC(Hb)Ts have been successfully utilised in health facilities in LMICs to diagnose childhood anaemia. However, limited evidence is available, and challenges exist that must be addressed before wider implementation. Further research is required to confirm accuracy, clinical benefits and cost-effectiveness.

Relevance of haemoglobin monitoring in apheresis plasma donors: A retrospective cohort study in Québec, Canada

BACKGROUND AND OBJECTIVES

Systematically measuring pre-donation haemoglobin (Hb) levels might be overly cautious for apheresis plasma donation, since plasmapheresis entails a small loss of red blood cells. We explored the association between the frequency of apheresis plasma donation and capillary blood Hb levels.

MATERIALS AND METHODS

This retrospective cohort study included donors who gave apheresis plasma at least twice between 24 October 2020 and 23 October 2022 in Québec, Canada. Results were stratified by sex and analysed with linear repeated-measure mixed models with random intercepts.

RESULTS

In total, 9535 men (mean age = 46.7 years) and 9409 women (mean age = 41.1 years) made ≥2, but no more than 16 apheresis plasma donations. Over an average of 9.2 months of observation, men maintained Hb levels well above the Hb deferral threshold, and their Hb levels decreased by only 0.17 g/dL between the 1st and 15th donation return (p < 0.0001). Over an average of 9.0 months of observation, women also maintained adequate Hb levels, and their Hb levels decreased by 0.08 g/dL between the 1st and 15th donation return.

CONCLUSION

The frequency of apheresis plasma donation was not associated with clinically meaningful changes in Hb levels, neither in men nor in women. This evidence questions the relevance of systematically monitoring Hb for apheresis plasma donation, at least for donation frequencies of ≤7-8 times per year. However, an adverse impact of plasmapheresis on Hb levels cannot be ruled out for individuals donating more frequently or for longer than ~9 months.

Accuracy of HemoCue301 portable hemoglobin analyzer for anemia screening in capillary blood from women of reproductive age in a deprived region of Northern Peru: An on-field study

OBJECTIVE

We aim to assess the accuracy and effectiveness of the HemoCue 301, a point-of-care (POC) device for measuring hemoglobin levels, and detecting anemia among individuals living in Tumbes, a rural, underserved area in Northern Peru.

METHODS

Baseline analysis of a clinical trial aimed at assessing the effect of multi-fortified bread (NCT05103709). Adult women with capillary blood HemoCue 301 readings below 12 g/dL were recruited in coastal city of Tumbes, Peru. A total of 306 women took part of the study, venous blood samples were taken and analyzed with an automated hematology analyzer. Serum samples were used to measure ferritin, serum iron and C reactive protein.

RESULTS

Capillary blood measured by the Hemocue 301 has a bias of 0.36 ± 0.93 g/dL respect to the automated Hb. More than 50% of women with normal ferritin values were classified as anemics according to the HemoCue 301. Automated Hb cut-off of 10.8 g/dL [AUC 0.82 (0.77-0.88)] had a specificity of 0.817 and a sensitivity 0.711 while with the HemoCue 301 cut-off of 11.1 g/dL [AUC 0.71 (0.62-0.79)] had a specificity of 0.697 and a sensitivity 0.688. The performance of the automated Hb cut-off was significantly better than the HemoCue (p<0.001).

CONCLUSION

Caution must be taken when using POC devices, especially with values around the threshold. Cut-off values found in our study could be used as surrogate means when no confirmatory tests are available. Clinical outcomes should be prioritized when diagnosing iron deficiency anemia in women of reproductive age to ensure proper diagnosis.

In-situ synthesis of ionic liquid-based-carbon quantum dots as fluorescence probe for hemoglobin detection

Carbon quantum dots (CQDs) have emerged as a potential fluorescent probe in bio/analytical chemistry in the present decade. The optical characteristics of CQDs may be tuned by their functional groups, which can also be used to selectively produce stable bonds with target molecules. Along with them, ionic liquids (ILs) are now demonstrating their important relevance in the field of pharmaceuticals for the creation of potent therapeutics. In the article, we have discussed the use of high fluorescent ILs-decorated-CQDs (CQDs-IM@OTf) as a straightforward and quick-acting fluorescence probe for sensitive and precise hemoglobin (Hb) determination with minimum detectability of 6.7 nM. The proposed mechanism behind this involves static mode of quenching which leads to the formation of a ground state complex [CQDs-IM@OTf-Hb complex] between the Hb protein and the drug. Despite the fact that Hb can quench the fluorescence of CQDs due to the inner filter effect (IFE) of the protein, which effects both the excitation and emission spectra of the CQDs, the addition of H₂O₂ improved the sensitivity of Hb detection. The present assay predicated on Hb interaction with H₂O₂, which produces reactive oxygen species such as hydroxyl (OH^.) and superoxide (O₂^.-) radicals under heme degradation and/or iron release from Hb. The subsequent reaction of hydroxyl radicals with CQDs, which acts as a strong oxidising agent, causes a high fluorescence quenching. The designed fluorescence probe was used to measure Hb in the concentration range of 3-90 nM with a precise detection limit of 0.33 nM. The quantification of hemoglobin (Hb) in diluted human blood samples is done using this observation.

Ethiopia National Food and Nutrition Survey to inform the Ethiopian National Food and Nutrition Strategy: a study protocol

INTRODUCTION

Ethiopia has made significant progress in reducing malnutrition in the past two decades. Despite such improvements, a substantial segment of the country's population remains chronically undernourished and suffers from micronutrient deficiencies and from increasing diet-related non-communicable diseases such as diabetes, hypertension and cancer. This survey aims to assess anthropometric status, dietary intake and micronutrient status of Ethiopian children, women and adolescent girls. The study will also assess coverage of direct and indirect nutrition-related interventions and map agricultural soil nutrients. The survey will serve as a baseline for the recently developed Ethiopian Food System Transformation Plan and will inform the implementation of the National Food and Nutrition Strategy.

METHODS AND ANALYSIS

As a population-based, cross-sectional survey, the study will collect data from the 10 regions and 2 city administrations of Ethiopia. The study population will be women of reproductive age, children aged 0-59 months, school-aged children and adolescent girls. A total of 16 596 households will be surveyed, allowing the generation of national and regional estimates. A two-stage stratified cluster sampling procedure will be used to select households. In the first stage, 639 enumeration areas (EAs) will be selected using probability-proportional-to-size allocation. In the second stage, 26 eligible households will be selected within each EA using systematic random selection. Primary outcomes include coverage of direct and indirect nutrition interventions, infant and young child feeding (IYCF) practices, food insecurity, dietary intakes, mental health, anthropometric status, micronutrient status and soil nutrient status.

ETHICS AND DISSEMINATION

The protocol was fully reviewed and approved by the Institutional Review Board of the Ethiopian Public Health Institute (protocol no: EPHI-IRB-317-2020). The study is based on voluntary participation and written informed consent is required from study participants. The findings will be disseminated via forums and conferences and will be submitted for publication in peer-reviewed journals.

A Low-Cost Test for Anemia Using an Artificial Neural Network

BACKGROUND

Anemia during pregnancy can complicate maternal and neonatal health and even lead to fatal consequences if not diagnosed early on. Around 99% of women who face maternal mortality are from middle or low-income countries. Early screening of anemia could facilitate improved health outcomes in pregnant women. Point of care techniques are preferred due to their ability to provide results rapidly and because they can be used by personnel with minimal or no training. Such techniques are especially useful in resource-constrained settings like rural parts of developing countries.

OBJECTIVES

The aim of the study was to develop a tool using an Artificial Neural Network (ANN) to estimate hemoglobin values using color information recorded from blood sample images. Our method utilizes inexpensive consumables and a simple image acquisition setup that can be assembled easily.

METHODS

This study explores a neural network model to estimate the hemoglobin content in an individual's blood sample. Blood samples were collected from 86 volunteers and the images of blood drops were obtained using an image acquisition setup designed by the team. The color intensity values calculated from the blood drop images were used as feature descriptors for the samples. The features obtained from our samples were consequently fed to the Artificial Neural Network.

RESULTS

Our neural network that gives the best result has the architecture of 11 neurons in each of the 5 layers. The best model gave estimated hemoglobin levels by analyzing color of blood samples with an accuracy of ±1.8 g/dl Limits of agreement (LOA) and bias 0.03 g/dl (with mean error of 0.75 g/dl). The model was subsequently tested with a validation set prepared from an additional 65 samples. The estimated hemoglobin levels gave an accuracy of +2 g/dl to -1.9 g/dl Limits of agreement (LOA) and bias 0.06 g/dl (with mean error of 0.78 g/dl).

CONCLUSION

Optimization of sensitivity and specificity has been able to achieve the sensitivity and specificity values as 95.5% and 52% respectively. These results are at par with the contemporary measurement techniques indicating that our method can be used as a workable screening technique itself.

Comparison of Anemia Screening Methods Using Paired Venous Samples in Women of Reproductive Age in Southern India

BACKGROUND

Anemia is an important public health problem, and accurate estimates may inform policy and programs. Although hemoglobin (Hb) assessment of venous blood via automated hematology analyzers (AHAs) is recommended, most population-based surveys estimate anemia prevalence based on analysis of capillary blood via portable hemoglobinometers.

OBJECTIVES

We aimed to evaluate screening methods for hemoglobin and anemia assessment using paired venous samples.

METHODS

Participants were women 15-40 y who were not pregnant or lactating. Paired venous whole blood samples (n = 896) were analyzed for hemoglobin (Hb) via portable hemoglobinometer (HemoCue 301) and Coulter Counter AHA. Anemia and severe anemia were defined as Hb <12.0g/dL and <8.0 g/dL, respectively. Bland-Altman methods were used to assess the level of agreement for Hb results (mean difference, SD of differences, limits of agreement). Diagnostic accuracy parameters (sensitivity, specificity, positive predictive value, negative predictive value, accuracy) were calculated to evaluate HemoCue performance compared to the AHA reference, overall and by sociodemographic, nutritional, and metabolic characteristics.

RESULTS

The estimated anemia prevalence was significantly lower via HemoCue vs. AHA (36.3% compared with 41.6%; P value < 0.0001). The HemoCue had 84.4% accuracy for anemia screening and 98.8% for severe anemia, compared to the AHA reference. The HemoCue had 74.8% sensitivity and 91.2% specificity, compared to AHA. HemoCue sensitivity was higher in women with iron deficiency [serum ferritin (SF) <15.0 μg/L: 81.6% compared with SF ≥15.0 μg/L: 41.3%], and lower in women with metabolic risk factors, including overweight [BMI ≥25.0 kg/m2: 63.9% vs. BMI <25.0 kg/m2: 78.8%], or elevated CRP (>1.0 mg/L: 67.2% vs. ≤1.0 mg/L: 82.9%), trunk fat (>35%: 62.7% vs. ≤35%: 80.1%), or whole-body fat (>35%: 63.9% vs. ≤35%: 80.3%).

CONCLUSIONS

Findings suggest that women with anemia may be incorrectly identified as not anemic via portable hemoglobinometer, and anemia prevalence may be underestimated at the population level.This study was registered at clinicaltrials.gov as NCT04048330.

Validity and Predictive Performance of Mini Nutritional Assessment Tool for Institutionalized Elders in Ethiopia

Background

Despite the high burden of malnutrition in the country, there is a lack of a simple and valid tool to screen elders in Ethiopia. The Mini Nutritional Assessment (MNA) tool has been validated for comprehensive geriatric assessment to identify malnutrition in other countries. However, there is a lack of evidence on the potential validity and reliability of the tool for institutionalized elders in Ethiopia. This study was aimed at determining the validity and predictive performance of MNA tool for malnutrition among Ethiopian institutionalized elderly.

Methods

A facility-based survey was conducted on randomly selected 164 elders in geriatric centers to evaluate the validity, reliability, and predictive performance of full MNA against hemoglobin (Hgb) and ideal body weight (IBW) measured under standard procedures. The data was presented in ROC graphs, and reliability was evaluated with Cronbach alpha. The receiver-operating characteristic curve (ROC) analysis was used to assess the predictive performance of the tool. The area under the curve (AUC) with its 95% CI was reported. The Youden index, at maximum sensitivity and specificity, was used to obtain optimal cutoff points.

Results

The internal consistency of the tool was good (α = 0.80). The full MNA score can better predict Hgb (AUC = 0.845; 0.783-0.899) and percentage of IBW (AUC = 0.90; 0.842-0.941) at specified cutoff points. A full MNA can predict malnutrition or risk of malnutrition based on percentage IBW at a sensitivity and specificity of 97.3% and 72.2%, respectively.

Conclusions

The full MNA has the potential to be a reliable and valid nutritional assessment tool for institutional elders.

Maternal anemia and baby birth size mediate the association between short birth interval and under-five undernutrition in Ethiopia: a generalized structural equation modeling approach

Background

Studies assessing the association between short birth interval, a birth-to-birth interval of less than 33 months, and under-five undernutrition have produced inconclusive results. This study aimed to assess the relationship between short birth interval and outcomes of stunting, underweight, and wasting among children aged under-five in Ethiopia, and potential mediation of any associations by maternal anemia and baby birth size.

Method

Data from the 2016 Ethiopia Demographic and Health Survey (EDHS) was used. Stunting, wasting, and underweight among children aged under-five were outcome variables. Generalized Structural Equation Modeling (GSEM) was used to examine associations between short birth interval and outcomes, and to assess hypothesized mediation by maternal anemia and baby birth size.

Results

Significant associations between short birth interval and stunting (AOR = 1.49; 95% CI = 1.35, 1.66) and underweight (AOR = 1.43; 95% CI = 1.28, 1.61) were found. There was no observed association between short birth interval and wasting (AOR = 1.05; 95% CI = 0.90, 1.23). Maternal anemia and baby birth size had a significant partial mediation effect on the association between short birth interval and stunting (the coefficient reduced from β = 0.337, p < 0.001 to β = 0.286, p < 0.001) and underweight (the coefficient reduced from β = 0.449, p < 0.001 to β = 0.338, p < 0.001). Maternal anemia and baby birth size mediated 4.2% and 4.6% of the total effect of short birth interval on stunting and underweight, respectively.

Conclusion

Maternal anemia and baby birth size were identified as mediators of the association between short birth interval and under-five undernutrition status. Policies and programs targeting the reduction of under-five undernutrition should integrate strategies to reduce maternal anemia and small baby birth size in addition to short birth interval.

Agreement between dried blood spots and HemoCue in Tamil Nadu, India

India retains the world’s largest burden of anemia despite decades of economic growth and anemia prevention programming. Accurate screening and estimates of anemia prevalence are critical for successful anemia control. Evidence is mixed on the performance of HemoCue, a point-of-care testing device most widely used for large-scale surveys. The use of dried blood spots (DBS) to assess hemoglobin (Hb) concentration is a potential alternative, particularly in field settings. The objective of this study is to assess Hb measurement agreement between capillary HemoCue and DBS among two age groups, children 6–59 months and females age 12–40 years. We analyzed data from the baseline round of a cluster randomized rice fortification intervention in Cuddalore district of Tamil Nadu, India. Capillary blood was collected from a subset of participants for Hb assessment by HemoCue 301 and DBS methods. We calculated Lin’s concordance correlation coefficient, and tested bias by conducting paired t-tests of Hb concentration. Independence of the bias and Hb magnitude was examined visually using Bland–Altman plots and statistically tested by Pearson’s correlation. We assessed differences in anemia classification using McNemar’s test of marginal homogeneity. Concordance between HemoCue and DBS Hb measures was moderate for both children 6–59 months (ρ_c = 0.67; 95% CI 0.65, 0.71) and females 12–40 years (ρ_c = 0.67: 95% CI 0.64, 0.69). HemoCue measures were on average 0.06 g/dL higher than DBS for children (95% CI 0.002, 0.12; p = 0.043) and 0.29 g/dL lower than DBS for females (95% CI − 0.34, − 0.23; p < 0.0001). 50% and 56% of children were classified as anemic according to HemoCue and DBS, respectively (p < 0.0001). 55% and 47% of females were classified as anemic according to HemoCue and DBS, respectively (p < 0.0001). There is moderate statistical agreement of Hb concentration between HemoCue and DBS for both age groups. The choice of Hb assessment method has important implications for individual anemia diagnosis and population prevalence estimates. Further research is required to understand factors that influence the accuracy and reliability of DBS as a methodology for Hb assessment.

A 2-year longitudinal follow-up of performance characteristics in Chinese male elite youth athletes from swimming and racket sports

Training in elite sport aims at the optimization of the athletic performance, and to control the athletes`progress in physiological, anthropometrical and motor performance prerequisites. However, in most sports, the value of longitudinal testing is unclear. This study evaluates the longitudinal development and the influence of intense training over 2-years on specific physiological performance prerequisites, as well as certain body dimensions and motor abilities in elite youth athletes. Recruited between 11-13 years of age at Shanghai Elite Sport school, the sample of student-athletes (N = 21) was categorized as the swimming group (10 athletes), and the racket sports group (11 players: 7 table tennis and 4 badminton players). The performance monitoring took place over two years between September 2016 and September 2018 and included 5 test waves. In all the test waves, the athletes were assessed by means of three physiological measurements (vital capacity, hemoglobin concentration, heart rate at rest), three anthropometric parameters (body height, body weight, chest girth), and two motor tests (back strength, complex reaction speed). Seven out of eight diagnostic methods exhibit medium to high validity to discriminate between the different levels of performance development in the two sports groups. The investigated development of the performance characteristics is attributed partly to the inherited athletic disposition as well as to the different sport-specific training regimens of the two sports groups.

Variability in haemoglobin concentration by measurement tool and blood source: an analysis from seven countries

OBJECTIVE

We explore factors such as the blood sampling site (capillary vs venous), the equipment (HemoCue vs automated haematology analyser) and the model of the HemoCue device (201+ vs 301) that may impact haemoglobin measurements in capillary and venous blood.

METHODS

Eleven studies were identified, and bias, concordance and measures of diagnostic performance were assessed within each study.

FINDINGS

Our analysis included 11 studies from seven countries (Cambodia, India, The Gambia, Ghana, Laos, Rwanda and USA). Samples came from children, men, non-pregnant women and pregnant women. Mean bias ranged from -8.7 to 2.5 g/L in Cambodian women, 6.2 g/L in Laotian children, 2.4 g/L in Ghanaian women, 0.8 g/L in Gambian children 6-23 months and 1.4 g/L in Rwandan children 6-59 months when comparing capillary blood on a HemoCue to venous blood on a haematology analyser. Bias was 8.3 g/L in Indian non-pregnant women and 2.6 g/L in Laotian children and women and 1.5 g/L in the US population when comparing capillary to venous blood using a HemoCue. For venous blood measured on the HemoCue compared with the automated haematology analyser, bias was 5.3 g/L in Gambian pregnant women 18-45 years and 11.3 g/L in Laotian children 6-59 months.

CONCLUSION

Our analysis found large variability in haemoglobin concentration measured on capillary or venous blood and using HemoCue Hb 201+ or Hb 301 or automated haematology analyser. We cannot ascertain whether the variation is due to differences in the equipment, differences in capillary and venous blood, or factors affecting blood collection techniques.

mHealth spectroscopy of blood hemoglobin with spectral super-resolution

Although blood hemoglobin (Hgb) testing is a routine procedure in a variety of clinical situations, noninvasive, continuous, and real-time blood Hgb measurements are still challenging. Optical spectroscopy can offer noninvasive blood Hgb quantification, but requires bulky optical components that intrinsically limit the development of mobile health (mHealth) technologies. Here, we report spectral super-resolution (SSR) spectroscopy that virtually transforms the built-in camera (RGB sensor) of a smartphone into a hyperspectral imager for accurate and precise blood Hgb analyses. Statistical learning of SSR enables us to reconstruct detailed spectra from three color RGB data. Peripheral tissue imaging with a mobile application is further combined to compute exact blood Hgb content without a priori personalized calibration. Measurements over a wide range of blood Hgb values show reliable performance of SSR blood Hgb quantification. Given that SSR does not require additional hardware accessories, the mobility, simplicity, and affordability of conventional smartphones support the idea that SSR blood Hgb measurements can be used as an mHealth method.

Hemoglobin concentration and anemia diagnosis in venous and capillary blood: biological basis and policy implications

Anemia is an important public health challenge and accurate prevalence estimates are needed for program planning and tracking progress. While venous blood assessed by automated hematology analyzers is considered gold standard, most population‐based surveys use point‐of‐care diagnostics and capillary blood to estimate population prevalence of anemia. Several factors influence hemoglobin (Hb) concentration, including human and analytic error, analysis method, and type of instrument, but it is unclear whether biological variability exists between venous and capillary blood. The objective of this paper was to systematically review sources of Hb variability and the potential biological basis for venous and capillary differences. We use data from a recent survey in the state of Uttar Pradesh, India, to illustrate the implications on anemia prevalence estimates. Significant differences in Hb concentration between capillary and venous blood samples are common. Most but not all find capillary Hb concentration to be higher than venous. Instrument/method variability and human error play an important role, but cannot fully explain these differences. A normative guide to data collection, analysis, and anemia diagnosis is needed to ensure consistent and appropriate interpretation. Further research is needed to fully understand the biological implications of venous and capillary Hb variability.

Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings

This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of ±7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0  g/L), WHO Colour Scale (0.5-10.0  g/L), paper-based devices (5.0-7.0  g/L), HemoCue® Hb-201 (1.0-16.0  g/L) and Hb-301 (0.5-6.0  g/L), and Masimo Pronto® (0.3-14.0  g/L) overestimated concentrations; (2) Masimo Radical®-7 both under- and overestimated concentrations (0.3-104.0  g/L); and (3) other methods underestimated concentrations (2.0-16.0  g/L). Most mean concentration comparisons varied less than ±7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.

Smartphone app for non-invasive detection of anemia using only patient-sourced photos

We introduce a paradigm of completely non-invasive, on-demand diagnostics that may replace common blood-based laboratory tests using only a smartphone app and photos. We initially targeted anemia, a blood condition characterized by low blood hemoglobin levels that afflicts >2 billion people. Our app estimates hemoglobin levels by analyzing color and metadata of fingernail bed smartphone photos and detects anemia (hemoglobin levels <12.5 g dL⁻¹) with an accuracy of ±2.4 g dL⁻¹ and a sensitivity of 97% (95% CI, 89–100%) when compared with CBC hemoglobin levels (n = 100 subjects), indicating its viability to serve as a non-invasive anemia screening tool. Moreover, with personalized calibration, this system achieves an accuracy of ±0.92 g dL⁻¹ of CBC hemoglobin levels (n = 16), empowering chronic anemia patients to serially monitor their hemoglobin levels instantaneously and remotely. Our on-demand system enables anyone with a smartphone to download an app and immediately detect anemia anywhere and anytime.

Anemia has a global prevalence of over 2 billion people and is diagnosed via blood-based laboratory test. Here the authors describe a smartphone app that can estimate hemoglobin levels and detect anemia by analyzing pictures of fingernail beds taken with a smartphone and without the need of any external equipment.

The WHO recommendation of home fortification of foods with multiple-micronutrient powders in children under 2 years of age and its effectiveness on anaemia and weight: a pragmatic cluster-randomized controlled trial

OBJECTIVE

To assess under real community settings the effectiveness of the WHO strategy of home fortification of foods (HFF) with multiple-micronutrient powders on Hb change, anaemia and weight in children.

DESIGN

A pragmatic cluster-randomized controlled trial.

SETTING

Forty villages in the Nioro Circle in Mali and 722 children aged 6-23 months were randomized to the intervention or control group. The intervention consisted of a daily dose of multiple-micronutrient powder for 3 months; in the control group, no supplement was given. In both groups, mothers received group education on child complementary feeding. Changes in weight, Hb concentration and anaemia were assessed as primary outcomes at baseline and 3 months. The HFF effect was determined using regression analyses and quantile regression with standard errors taking account of the cluster design.

SUBJECTS

Children aged 6-23 months.

RESULTS

Overall prevalence of anaemia in the sample was high: 90 %. HFF provided a modest but statistically significant Hb change v. no intervention (0·50 v. 0·09 g/dl, P=0·023). Prevalence of anaemia changed little: 91·3-85·8 % (P=0·04) in the intervention group v. 88·1-87·5 % % (P=0·86) in the control group. Proportion of severe anaemia was reduced by 84 % (from 9·8 to 1·6 %) in the intervention group, but increased in the control group (from 8·5 to 10·8 %). No effect was observed on weight.

CONCLUSIONS

The WHO HFF strategy to fight anaemia showed a modest change on Hb concentration and significantly reduced the rate of severe anaemia.

CD4 Lymphocyte Enumeration and Hemoglobin Assessment Aid for Priority Decisions: A Multisite Evaluation of the BD FACSPresto™ System

Background:

The BD FACSPresto^™ system uses capillary and venous blood to measure CD4 absolute counts (CD4), %CD4 in lymphocytes, and hemoglobin (Hb) in approximately 25 minutes. CD4 cell count is used with portable CD4 counters in resource-limited settings to manage HIV/AIDS patients. A method comparison was performed using capillary and venous samples from seven clinical laboratories in five countries. The BD FACSPresto system was assessed for variability between laboratory, instrument/operators, cartridge lots and within-run at four sites.

Methods:

Samples were collected under approved voluntary consent. EDTA-anticoagulated venous samples were tested for CD4 and %CD4 T cells using the gold-standard BD FACSCalibur^™ system, and for Hb, using the Sysmex^® KX-21N^™ analyzer. Venous and capillary samples were tested on the BD FACSPresto system. Matched data was analyzed for bias (Deming linear regression and Bland-Altman methods), and for concordance around the clinical decision point. The coefficient of variation was estimated per site, instrument/operator, cartridge-lot and between-runs.

Results:

For method comparison, 93% of the 720 samples were from HIV-positive and 7% from HIV-negative or normal subjects. CD4 and %CD4 T cells venous and capillary results gave slopes within 0.96–1.05 and R² ≥0.96; Hb slopes were ≥1.00 and R² ≥0.89. Variability across sites/operators gave %CV <5.8% for CD4 counts, <1.9% for %CD4 and <3.2% for Hb. The total %CV was <7.7% across instrument/cartridge lot.

Conclusion:

The BD FACSPresto system provides accurate, reliable, precise CD4/%CD4/Hb results compared to gold-standard methods, irrespective of venous or capillary blood sampling. The data showed good agreement between the BD FACSPresto, BD FACSCalibur and Sysmex systems.

Effects of preanalytical factors on hemoglobin measurement: A comparison of two HemoCue® point-of-care analyzers

BACKGROUND

In field studies, hemoglobin (Hb) is often measured using a battery-operated, portable HemoCue® hemoglobinometer.

METHODS

We compared the performance of 2 HemoCue® models (Hb-201+ and Hb-301) and investigated effects of preanalytical factors on Hb results by simulating unfavorable field conditions.

RESULTS

The Hb-301 produced 2.6% higher results compared to the Hb-201+. Hb had to be measured within 1min of filling the Hb-301 cuvette to avoid artificially elevated concentrations (1.3% per min). The Hb-301 cuvettes withstood elevated temperature (37°C) and humidity (72%) for 3weeks, while the Hb-201+ cuvettes degraded within 10min under those conditions. Both cuvette types withstood elevated temperature for 3weeks. Properly-collected venous and capillary blood produced comparable results. Pooled capillary blood produced comparable results to the second and third but not the fourth drop of blood (3.3% lower). Blood could be stored for ≤4days at 10-30°C before Hb-201+ measurement, but only for 1day at 10-23°C before Hb-301 measurement (≤1% change in Hb).

CONCLUSIONS

Higher Hb results obtained with the Hb-301 may influence the interpretation of anemia prevalence in health surveys. While the Hb-301 performed better in high humidity conditions, the Hb-201+ provided more user flexibility regarding delayed Hb reading.