The difference between fingerstick and venous hemoglobin and hematocrit varies by sex and iron stores

Association of Retinal Vein Occlusion With Serum Osmolality and Hydration Status

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate serum osmolality and hydration status in patients with retinal vein occlusion (RVO).

PATIENTS AND METHODS

This cross-sectional study consisted of 79 patients with RVO and 81 age- and sex-matched peers without ocular disease. Data were collected from patient records and included a comprehensive ophthalmological examination, laboratory data of fasting blood test results, and internal medicine outpatient examination. Complete blood count and levels of fasting glucose, sodium, blood urea nitrogen (BUN), creatinine, triglyceride, low-density lipoprotein, high-density lipoprotein, HbA1c, and serum osmolality were evaluated. BUN/creatinine ratios were calculated.

RESULTS

Mean serum sodium and serum osmolality levels were 142.53 ± 2.13 and 139.74 ± 2.16 mEq/L and 286.58 ± 4.40 and 280.57 ± 4.39 mOsmol/kg H2O in the RVO and control groups, respectively. Serum osmolality and serum sodium levels, and BUN/creatinine ratio were significantly higher in the RVO group than in controls (P < 0.05 for all).

CONCLUSIONS

We found that serum osmolality, sodium levels, and the BUN/creatinine ratio increased significantly in the RVO group. The results suggest dehydration status may affect the genesis of vessel occlusion in RVO. [Ophthalmic Surg Lasers Imaging Retina 2024;55:130-135.].

Molecular biomarkers for assessing the heat-adapted phenotype: a narrative scoping review

Heat acclimation/acclimatisation (HA) mitigates heat-related decrements in physical capacity and heat-illness risk and is a widely advocated countermeasure for individuals operating in hot environments. The efficacy of HA is typically quantified by assessing the thermo-physiological responses to a standard heat acclimation state test (i.e. physiological biomarkers), but this can be logistically challenging, time consuming, and expensive. A valid molecular biomarker of HA would enable evaluation of the heat-adapted state through the sampling and assessment of a biological medium. This narrative review examines candidate molecular biomarkers of HA, highlighting the poor sensitivity and specificity of these candidates and identifying the current lack of a single 'standout' biomarker. It concludes by considering the potential of multivariable approaches that provide information about a range of physiological systems, identifying a number of challenges that must be overcome to develop a valid molecular biomarker of the heat-adapted state, and highlighting future research opportunities.

Hilab System Device in an Oncological Hospital: A New Clinical Approach for Point of Care CBC Test, Supported by the Internet of Things and Machine Learning

The complete blood count (CBC) is a highly requested test that is generally restricted to centralized laboratories, which are limited by high cost, being maintenance-demanding, and requiring costly equipment. The Hilab System (HS) is a small, handheld hematological platform that uses microscopy and chromatography techniques, combined with machine learning (ML) and artificial intelligence (AI), to perform a CBC test. This platform uses ML and AI techniques to add higher accuracy and reliability to the results besides allowing for faster reporting. For clinical and flagging capability evaluation of the handheld device, the study analyzed 550 blood samples of patients from a reference institution for oncological diseases. The clinical analysis encompassed the data comparison between the Hilab System and a conventional hematological analyzer (Sysmex XE-2100) for all CBC analytes. The flagging capability study compared the microscopic findings from the Hilab System and the standard blood smear evaluation method. The study also assessed the sample collection source (venous or capillary) influences. The Pearson correlation, Student t-test, Bland-Altman, and Passing-Bablok plot of analytes were calculated and are shown. Data from both methodologies were similar (p > 0.05; r ≥ 0.9 for most parameters) for all CBC analytes and flagging parameters. Venous and capillary samples did not differ statistically (p > 0.05). The study indicates that the Hilab System provides humanized blood collection associated with fast and accurate data, essential features for patient wellbeing and quick physician decision making.

Comparison of Two Methods of Capillary Sampling in Blood Pre-Donation Anemia Screening in Brazil

BACKGROUND

The laboratory tests most used by blood banks to diagnose anemia are the hemoglobin (Hb) and microhematocrit (Hct) tests, measured from capillary samples.

OBJECTIVE

To analyze the two capillary screening methods for pre-donation anemia by comparing their agreement in diagnosing anemia.

METHOD

A cross-sectional study in a population of 15,521 blood donation candidates for whom information was available on Hb and Hct, performed from capillary blood samples. Hb was determined using the HemoCue^® test and Hct by the centrifugation method. The Kappa coefficient was calculated to assess the agreement between the methods. Pearson's correlation tests and gender-adjusted linear regression were used to assess the change in the response variable (Hb) as a function of the explanatory variable (Hct).

RESULTS

The majority of the study population were men (70.4%), aged between 18 and 44 years (72.1%), who declared themselves white or mixed skin color (85.6%), and had undergone at least 11 years of complete education (72.4%). The Kappa coefficient found was 92.7 and 99.2 for women and men, respectively. Pearson's correlation showed a correlation coefficient of 0.98 and the linear regression graph showed an adequate relationship between the tests with R² = 0.97.

CONCLUSIONS

Comparing the Hb and Hct capillary tests, it was found that Hct can be safely used to screen for anemia in pre-blood donation.

Blood draw site and analytic device influence hemoglobin measurements

Anemia is a continuing global public health concern and a priority for international action. The prevalence of anemia is estimated from the hemoglobin (Hb) levels within target populations, yet the procedures for measuring Hb are not standardized and different approaches may result in discrepancies. Several analytical variables have been proposed to influence Hb measurements, but it is difficult to understand the impact on specific variables from large population or field studies. Therefore, we designed a highly controlled protocol that minimized most technical parameters to specifically investigate the impact of blood draw site and analytic device on Hb measurements. A diverse cohort of sixty healthy adults each provided a sequential capillary and venous blood sample that were measured for Hb using an automated hematology analyzer (ADVIA-2120) and two point-of-care devices (HemoCue 201+ and HemoCue 301). Comparing blood draw sites, the mean Hb content was 0.32-0.47 g/dL (2-4%) higher in capillary compared to venous blood from the same donors. Comparing different Hb measuring instruments, the mean Hb content was 0.19-0.46 g/dL (1-4%) higher measured with HemoCue devices compared to ADVIA-2120 in both capillary and venous blood from the same donors. The maximum variance in measurement was also higher with HemoCue devices using blood from venous (5-6% CV) and capillary (21-25% CV) sites compared to ADVIA-2120 (0.6-2% CV). Other variables including blood collection tube manufacturer did not affect mean Hb content. These results demonstrate that even when most technical variables are minimized, the blood draw site and the analytical device can have a small but statistically significant effect on the mean and dispersion of Hb measurements. Even in this study, the few participants identified as mildly anemic using venous blood measured by ADVIA-2120 would not have been classified as anemic using their capillary blood samples or point-of-care analyzers. Thus, caution is warranted when comparing Hb values between studies having differences in blood draw site and Hb measuring device. Future anemia testing should maintain consistency in these analytical variables.

Bringing the lab bench to the field: Point-of-care testing for enhancing health research and stakeholder engagement in rural/remote, indigenous, and resource-limited contexts

Point-of-care testing (POCT) allows researchers and health-care providers to bring the lab bench to the field, providing essential health information that can be leveraged to improve health care, accessibility, and understanding across clinical and research settings. Gaps in health service access are most pronounced in what we term RIR settings-rural/remote regions, involving Indigenous peoples, and/or within resource-limited settings. In these contexts, morbidity and mortality from infectious and non-communicable diseases are disproportionately higher due to numerous geographic, economic, political, and sociohistorical factors. Human biologists and global health scholars are well-positioned to contribute on-the-ground-level insights that can serve to minimize global health inequities and POCT has the potential to augment such approaches. While the clinical benefits of POCT include increasing health service access by bringing testing, rapid diagnosis, and treatment to underserved communities with limited pathways to centralized laboratory testing, POCT also provides added benefits to both health-focused researchers and their participants. Through portable, minimally invasive devices, researchers can provide actionable health data to participants by coupling POCT with population-specific health education, discussing results and their implications, creating space for participants to voice concerns, and facilitating linkages to treatment. POCT can also strengthen human biology research by shedding light on questions of evolutionary and biocultural importance. Here, we expand on the epidemiological and research value, as well as practical and ethical challenges of POCT across stakeholders (i.e., participant, community, health researcher, and trainee). Finally, we emphasize the immense opportunities of POCT for fostering collaborative research and enhancing access to health delivery and information and, by extension, helping to mitigate persistent global health inequities.

Horiba Micros ES 60 Blood Cell Analyzer in Blood Donor Eligibility: A Validation Study

Background: Eligibility criteria for blood donation require hemoglobin levels of ≥12.5 g/dL for women and ≥13.5 g/dL for men, and a platelet count of ≥180 × 109/L. Screening methods before donation should ensure high accuracy, precision, and ease in operation. We assessed the performance, precision, and repeatability of the Horiba Micros ES 60 (Horiba) compared to the Beckman Coulter DXH 800. Methods: Performance was compared by testing samples for each of the 11 devices across 6 sites in the Transfusion Service of Friuli Venezia Giulia Region, Italy. We measured precision by calculating the coefficient of variation (CV), concordance with ρ-Pearson’s correlation coefficient, and accuracy with F-tests. The intra-assay agreement was examined in the 11 devices, and repeatability was performed by using CV and the Kruskal−Wallis test. Results: The precision of Horiba was acceptable. Overall, ρ-Pearson’s coefficients indicated a strong correlation and positive relationship between all variables. The Bland−Altman plots showed that most of the differences lay within the limits of agreement. All CV were below the reference threshold for all the parameters. Finally, the Kruskal−Wallis test reported non-significant statistical differences for all parameters, except platelet count (p < 0.000). Conclusions: Horiba is adequate for routine pre-donation screening. The intra-assay agreement further demonstrates the accuracy of the device.

Hilab system, a new point-of-care hematology analyzer supported by the Internet of Things and Artificial Intelligence

The complete blood count (CBC) is one of the most requested tests by physicians. CBC tests, most realized in conventional hematological analyzers, are restricted to centralized laboratories due to frequent maintenance, large devices, and expensive costs required. On the other hand, most handheld CBC devices commercially available show high prices and are not liable to calibration or control procedures, which results in poor quality compared to standard hematology instruments. The Hilab system is a small-handed hematological platform that uses microscopy and chromatography techniques for blood cells and hematimetric parameters analysis through artificial intelligence, machine learning, and deep learning techniques. For clinical evaluation of the handheld CBC device, 450 blood samples were analyzed. The samples encompassed normal (82%) and pathological conditions (18%), such as thalassemias (2.2%), anemias (6.6%), and infections (9.2%). For all analytes, accuracy, precision, method comparison, and flagging capabilities of the Hilab System, were compared with the Sysmex XE-2100 (Sysmex, Japan) results. The sample source (venous and capillary) influences were also evaluated. Pearson correlation, Student t test, bias, and the Bland-Altman plot of each blood count analyte were calculated and shown. The significance level was set at p ≤ 0.05. For clinical evaluation, Hilab System and the Sysmex XE-2100 showed a strong correlation (r ≥ 0.9) for most evaluated parameters. In the precision study, analytes showed CV inside the limits established according to European Federation of Clinical Chemistry and Laboratory Medicine guidelines. The flagging capabilities of the Hilab system, compared to the manual microscopy technique, presented high sensibility, specificity, and accuracy. Venous and capillary samples (p > 0.05) do not differ statistically. Considering the need for point-of-care CBCs, the study indicated that the Hilab system provides fast, accurate, low cost, and robust analysis for reliable clinical use.

Association of anemia with functional outcomes in patients with mechanical thrombectomy

INTRODUCTION

Anemia at presentation is associated with worse outcomes in patients with acute ischemic stroke (AIS). We aim to investigate the association of anemia parameters with functional dependence and mortality in patients who undergo mechanical thrombectomy (MT).

METHODS

We performed a retrospective chart review of patients who underwent MT for an anterior circulation large vessel occlusion at a comprehensive stroke center from 1/2015-6/2020. Anemia was considered as a dichotomous categorical variable with a cutoff point of hemoglobin (Hb) < 12.0 g/dL in women and < 13.0 g/dL in men, as per the definition of the World Health Organization. Mean values of Hb and hematocrit (HCT) were obtained over the first five days of admission. Hemoglobin and HCT variability were measured using standard deviation (SD), and coefficient variability (CV) over the first five days of admission. Values of variance and difference (the difference between peak and trough of Hemoglobin or HCT) were also recorded. Multivariate logistic regression analyses were performed, including the predictor variables which were contributing significantly to the model (P < 0.05) in the univariate analysis, with 30-day functional dependence (mRS 3-6) (primary outcome) and 30-day mortality (secondary outcome) as the dependent variables.

RESULTS

188 patients met our inclusion criteria. Anemia on presentation, lower mean and minimum values of five-day Hb and HCT, and higher variability in five-day Hb and HCT parameters were associated with higher 3-month mortality. Men with lower mean and minimum values of five-day Hb and HCT had a significantly higher likelihood of functional dependence at 3-months. This finding was not replicated amongst women in our cohort.

CONCLUSION

Our study demonstrated higher 3-mortality in patients with anemia and Hb variability. Our study also demonstrated a higher likelihood of functional dependence in patients amongst men with anemia.

Reproducibility and validity of portable haemoglobinometer for the diagnosis of anaemia in children under the age of 5 years

Portable haemoglobinometers have been used in order to estimate the prevalence of anaemia in diverse settings. However, few studies have been conducted to evaluate their performance in children of different age groups in distinct epidemiological contexts. To evaluate the reproducibility and reliability of a portable haemoglobinometer for the diagnosis of anaemia in children <5 years Hb was measured in the venous blood of 351 children <5 years by an automated system (standard method) and in three capillary blood samples, using a portable haemoglobinometer (HemoCue^®; test method). The reproducibility of the device and of the test method was evaluated using the intraclass correlation coefficient (ICC) (Hb in its continuous form), κ and prevalence-adjusted bias-adjusted κ (PABAK) (categorised variable: anaemia: yes/no). For test method validation, Bland-Altman analyses were performed and sensitivity, specificity, accuracy rate, positive predictive value (PPV) and negative predictive values (NPV) were calculated. The haemoglobinometer presented good device reproducibility (ICC = 0·79) and reasonable method reproducibility (puncture, collection and reading) (ICC = 0·71). Superficial and fair agreement (κ) and good agreement (PABAK) were observed among the diagnoses obtained through the test method. The prevalence of anaemia was 19·1 and 19·7 % using the standard and the test method, respectively, with no statistically significant differences. The test method presented higher specificity (87·7 %) and NPV (88·3 %) than sensitivity (50·7 %) and PPV (49·3 %), and intermediary accuracy rate (57·8 %). HemoCue^® showed good device reproducibility and reasonable method reproducibility, as well as good performance in estimating the prevalence of anaemia. Nevertheless, it showed a fair reliability and low individual diagnostic accuracy.

Application of volumetric absorptive microsampling (VAMS) to measure multidimensional anti-influenza IgG antibodies by the mPlex-Flu assay

Introduction: Recently, volumetric absorptive microsampling (VAMS) has been used for accurate sampling of a fixed peripheral blood volume (10 µL) on a volumetric swab, and long-term sample storage. The mPlex-Flu assay is a novel, high-throughput assay that simultaneously measures the concentration of antibodies against the hemagglutinin (HA) proteins from multiple influenza virus strains with ≤5 µL of serum. Here we describe combining these two methods to measure multidimensional anti-influenza IgG activity in whole blood samples collected by a finger stick and VAMS, with correction for serum volume based on simultaneous hemoglobin measurement. Methods: We compared capillary blood samples obtained from a finger stick using a VAMS device with serum samples collected by traditional phlebotomy from 20 subjects, with the influenza antibody profiles measured by the mPlex-Flu assay. Results: We found that results with the two sampling methods were highly correlated within subjects and across all influenza strains (mean R 2 = 0.9470). Adjustment for serum volume, based on hemaglobin measurement, was used to estimate serum volume of samples and improved the accuracy. IgG measurements were stable over 3 weeks when VAMS samples were stored at room temperature or transported using a variety of shipping methods. Additionally, when volunteers performed finger-stick VAMS at-home by themselves, the comparison results of anti-HA antibody concentrations were highly consistent with sampling performed by study personnel on-site (R 2 = 0.9496). Conclusions: This novel approach can provide a simple, accurate, and low-cost means for monitoring the IgG anti-influenza HA antibody responses in large population studies and clinical trials.

Association between type of contraceptive use and haemoglobin status among women of reproductive age in 24 sub-Saharan Africa countries

BACKGROUND

Little is known whether contraceptive methods differentially modify women's risk of anaemia or not. We compared the haemoglobin status of women currently using different fertility regulation methods in sub-Saharan Africa (SSA) where anaemia is a major concern.

METHODS

We conducted the study based on the secondary data of 24 nationally representative demographic and health surveys carried out recently in SSA. The data of 105 532 women were included in the analysis. In the original surveys, respondents were selected using multistage sampling techniques and haemoglobin was determined using the HemoCue analyser. The association between method of contraception and anaemia status was determined via a mixed-effects logistic regression model adjusted for potential confounders. The outputs are presented using adjusted odds ratio (AOR) with 95% CI.

RESULTS

The mean (±SD deviation) haemoglobin was 12.3 (±1.7) g/dl and 36.7% of the women had anaemia. Current use of modern contraceptives, as compared with non-use, was associated with a 25% reduction (AOR=0.75 (95% CI: 0.73 to 0.78)) in the odds of anaemia. Comparison among individual modern methods showed, as compared with current barrier methods users, use of injectables (AOR=0.62 (95% CI: 0.57 to 0.67)), oral contraceptive pills (OCP) (AOR=0.62 (95% CI: 0.57 to 0.66)) and implants (AOR=0.63 (95% CI: 0.58 to 0.70)) were significantly associated with reduced odds of anaemia. With reference to women with less than 12 months of use, the odds were significantly reduced by about a quarter among women with more than 12 months of OCP or injectables use.

CONCLUSION

The use of hormonal contraceptives is associated with lower odds of anaemia.

Automated end-to-end blood testing at the point-of-care: Integration of robotic phlebotomy with downstream sample processing

Diagnostic blood testing is the most commonly performed clinical procedure in the world, and influences the majority of medical decisions made in hospital and laboratory settings. However, manual blood draw success rates are dependent on clinician skill and patient physiology, and results are generated almost exclusively in centralized labs from large-volume samples using labor-intensive analytical techniques. This paper presents a medical device that enables end-to-end blood testing by performing blood draws and providing diagnostic results in a fully automated fashion at the point-of-care. The system couples an image-guided venipuncture robot, developed to address the challenges of routine venous access, with a centrifuge-based blood analyzer to obtain quantitative measurements of hematology. We first demonstrate a white blood cell assay on the analyzer, using a blood mimicking fluid spiked with fluorescent microbeads, where the area of the packed bead layer is correlated with the bead concentration. Next we perform experiments to evaluate the pumping efficiency of the sample handling module. Finally, studies are conducted on the integrated device - from blood draw to analysis - using blood vessel phantoms to assess the accuracy and repeatability of the resulting white blood cell assay.

Techniques used for the screening of hemoglobin levels in blood donors: current insights and future directions

Blood donor hemoglobin (Hb) estimation is an important donation test that is performed prior to blood donation. It serves the dual purpose of protecting the donors' health against anemia and ensuring good quality of blood components, which has an implication on recipients' health. Diverse cutoff criteria have been defined world over depending on population characteristics; however, no testing methodology and sample requirement have been specified for Hb screening. Besides the technique, there are several physiological and methodological factors that affect accuracy and reliability of Hb estimation. These include the anatomical source of blood sample, posture of the donor, timing of sample and several other biological factors. Qualitative copper sulfate gravimetric method has been the archaic time-tested method that is still used in resource-constrained settings. Portable hemoglobinometers are modern quantitative devices that have been further modified to reagent-free cuvettes. Furthermore, noninvasive spectrophotometry was introduced, mitigating pain to blood donor and eliminating risk of infection. Notwithstanding a tremendous evolution in terms of ease of operation, accuracy, mobility, rapidity and cost, a component of inherent variability persists, which may partly be attributed to pre-analytical variables. Hence, blood centers should pay due attention to validation of test methodology, competency of operating staff and regular proficiency testing of the outputs. In this article, we have reviewed various regulatory guidelines, described the variables that affect the measurements and compared the validated technologies for Hb screening of blood donors along with enumeration of their merits and limitations.

Poor Validity of Noninvasive Hemoglobin Measurements by Pulse Oximetry Compared with Conventional Absorptiometry in Children in Côte d'Ivoire

Anemia remains a major public health issue in many African communities. We compared a novel, commercially available noninvasive hemoglobin (Hb)-measuring device to direct Hb measurements by finger-prick samples in a pediatric cohort in rural Côte d'Ivoire. Noninvasive Hb measurements were attempted in 191 children 2-15 years of age and obtained in 102 (53.5%) children. The median Hb for the 102 children was 12.0 g/dL (interquartile range [IQR] = 11.3-12.7 g/dL) for conventional absorptiometry and 13.3 g/dL (IQR = 12.1-14.2 g/dL) for noninvasive measurements. A Bland-Altman analysis demonstrated a median bias of +1.1 g/dL (IQR = 0.4-2.0 g/dL), with greater overestimation of Hb by noninvasive testing occurring at low Hb values. This overestimation of the noninvasive Hb-measuring device to direct Hb measurements persisted across preschool- and school-aged children, and both sexes. The Pearson correlation coefficient was 0.50 for children 4-9 years of age, and 0.33 for children 10-15 years of age. Further study and development of noninvasive Hb devices is necessary prior to implementation in African pediatric populations.

Point of care hemoglobin testing in plateletpheresis donors: Noninvasive versus invasive methods

BACKGROUND

Predonation hemoglobin (Hb) for plateletpheresis donors is estimated by presently available invasive methods. Venous samples of only those donors whose Hb is more than 12.5 g/dl are screened for complete blood count and transfusion transmissible infections. There is a pressing need to substitute this invasive Hb test with noninvasive one to reduce donor discomfort and avoid further pricking the donor. We therefore went ahead with the aim of comparing a noninvasive Hb estimation method NBM 200 with the invasive method - Hemocue, taking SYSMEX KX-21 as a gold standard.

METHODS

500 voluntary consenting plateletpheresis donors qualifying the laid down criteria for platelet donation were included in the study. Hb readings obtained by the NBM 200 and Hemocue were compared to those obtained from the fully automated hematology analyzer SYSMEX KX-21.

RESULTS

Coefficients of correlation were found to be statistically significant at <0.0001 level of confidence. Results of Friedman's test on the three methods also showed significant difference in means. Bland-Altman plots and mountain plots also confirm the same. NBM 200 was found to be more sensitive, specific, and precise than Hemocue in detecting ineligible donors.

CONCLUSION

NBM 200 was found to be more sensitive, specific, and precise as compared to Hemocue for predonation screening of Hb in plateletpheresis donors and the prime benefit it offers is that it is 'noninvasive' thereby assisting in stemming the platelet donor pool. The onus lies on the blood transfusion services to make use of appropriately validated gadgets that reduce the donor discomfort.

Serum ferritin in plateletpheresis and whole blood donors

BACKGROUND AND OBJECTIVES

We performed a prospective analysis of iron status in plateletpheresis donors, using whole blood donors as a control group, to assess the haematinic effects of regular anti-coagulated extracorporeal circulation and platelet collection.

MATERIALS AND METHODS

Ferritin levels were measured in samples from 31 regular male plateletpheresis donors and from 14 first time male whole blood donors, immediately before and immediately after donation, and immediately before the next donation. An additional 33 regular male plateletpheresis donors and 17 first time male whole blood donors had serum ferritin levels checked predonation.

RESULTS

Male plateletpheresis donors had a statistically significant fall in serum ferritin after donation (P = 0.005)*. In addition, male platelet donors had significantly lower serum ferritin levels than first time male blood donors: ferritin <20 µg/L was found in 6/64 (9%) of regular platelet donors and 1/31 (3%) of first time blood donors (P < 0.001)*.

DISCUSSION

Our studies support the value of serum ferritin measurement in apheresis donor management.

A Novel, Nondestructive, Dried Blood Spot-Based Hematocrit Prediction Method Using Noncontact Diffuse Reflectance Spectroscopy

Dried blood spot (DBS) sampling is recognized as a valuable alternative sampling strategy both in research and in clinical routine. Although many advantages are associated with DBS sampling, its more widespread use is hampered by several issues, of which the hematocrit effect on DBS-based quantitation remains undoubtedly the most widely discussed one. Previously, we developed a method to derive the approximate hematocrit from a nonvolumetrically applied DBS based on its potassium content. Although this method yielded good results and was straightforward to perform, it was also destructive and required sample preparation. Therefore, we now developed a nondestructive method which allows to predict the hematocrit of a DBS based on its hemoglobin content, measured via noncontact diffuse reflectance spectroscopy. The developed method was thoroughly validated. A linear calibration curve was established after log/log transformation. The bias, intraday and interday imprecision of quality controls at three hematocrit levels and at the lower and upper limit of quantitation (0.20 and 0.67, respectively) were less than 11%. In addition, the influence of storage and the volume spotted was evaluated, as well as DBS homogeneity. Application of the method to venous DBSs prepared from whole blood patient samples (n = 233) revealed a good correlation between the actual and the predicted hematocrit. Limits of agreement obtained after Bland and Altman analysis were -0.076 and +0.018. Incurred sample reanalysis demonstrated good method reproducibility. In conclusion, mere scanning of a DBS suffices to derive its approximate hematocrit, one of the most important variables in DBS analysis.

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

In South Africa, various point-of-care hemoglobin meters are used. However, the regulatory framework for approval, implementation and oversight of use of point-of-care hemoglobin meters is suboptimal. We assessed the diagnostic accuracy of the HemoCue Hb 301, STAT-Site MHgb and URIT-12 point-of-care hemoglobin meters, compared to a central laboratory based reference assay, in a central laboratory and a community based clinic in Durban, South Africa. Differences in performance of the point-of-care assays, compared to the reference assay, were more pronounced in the community based clinic. Results were reasonable for the HemoCue Hb 301, but poor for the STAT-Site MHgb and the URIT-12. Poor test performance of point-of-care hemoglobin meters, and inadequate evaluations and oversight in South Africa, leads to suboptimal clinical care and clinical research, and increased costs. There is a need for proper evaluation and quality assurance of point-of-care tests, the results of which should be made widely available to key stakeholders.

Low-grade inflammation is associated with lower haemoglobin levels in healthy individuals: results from the Danish blood donor study

BACKGROUND AND OBJECTIVES

Chronic inflammation can lead to anaemia of chronic disease due to the sequestration of iron caused by inflammatory cytokines and the protein hepcidin. However, the effect of low-grade inflammation (LGI) on haemoglobin among healthy individuals is not known. This study examines the effect of LGI on haemoglobin among Danish blood donors.

MATERIALS AND METHODS

We performed multivariable linear regression to assess the effect of LGI (i.e. high-sensitivity C-reactive protein above 3 mg/l but below 10 mg/l) on haemoglobin in 17 322 Danish blood donors. We also performed multivariable logistic regression to evaluate the effect of LGI on the risk of having low haemoglobin (below the 10th percentile among men and women, respectively). We adjusted for donation activity, age, sex, low ferritin, oral contraceptives and menopause. All analyses were stratified by current smoking status.

RESULTS

LGI was associated with lower haemoglobin (0·08 mm lower [0·12 g/dl], 95% confidence interval (CI): -0·11-0·05) and increased risk of low haemoglobin (OR = 1·22, 95% CI: 1·05-1·43) in non-smokers. Conversely, LGI was associated with higher haemoglobin in smokers (0·12 mm [0·19 g/dl], 95% CI: 0·06-0·18).

CONCLUSION

In this first study of LGI and haemoglobin in healthy individuals, there was a negative association between LGI and haemoglobin in non-smokers. The association was positive in smokers, probably because smoking leads to both increased inflammation and increased haemoglobin through CO exposure.

Oral iron supplementation after blood donation: a randomized clinical trial

IMPORTANCE

Although blood donation is allowed every 8 weeks in the United States, recovery of hemoglobin to the currently accepted standard (12.5 g/dL) is frequently delayed, and some donors become anemic.

OBJECTIVE

To determine the effect of oral iron supplementation on hemoglobin recovery time (days to recovery of 80% of hemoglobin removed) and recovery of iron stores in iron-depleted ("low ferritin," ≤26 ng/mL) and iron-replete ("higher ferritin," >26 ng/mL) blood donors.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, nonblinded clinical trial of blood donors stratified by ferritin level, sex, and age conducted in 4 regional blood centers in the United States in 2012. Included were 215 eligible participants aged 18 to 79 years who had not donated whole blood or red blood cells within 4 months.

INTERVENTIONS

One tablet of ferrous gluconate (37.5 mg of elemental iron) daily or no iron for 24 weeks (168 days) after donating a unit of whole blood (500 mL).

MAIN OUTCOMES AND MEASURES

Time to recovery of 80% of the postdonation decrease in hemoglobin and recovery of ferritin level to baseline as a measure of iron stores.

RESULTS

The mean baseline hemoglobin levels were comparable in the iron and no-iron groups and declined from a mean (SD) of 13.4 (1.1) g/dL to 12.0 (1.2) g/dL after donation in the low-ferritin group and from 14.2 (1.1) g/dL to 12.9 (1.2) g/dL in the higher-ferritin group. Compared with participants who did not receive iron supplementation, those who received iron supplementation had shortened time to 80% hemoglobin recovery in both the low-ferritin (mean, 32 days, interquartile range [IQR], 30-34, vs 158 days, IQR, 126->168) and higher-ferritin groups (31 days, IQR, 29-33, vs 78 days, IQR, 66-95). Median time to recovery to baseline ferritin levels in the low-ferritin group taking iron was 21 days (IQR, 12-84). For participants not taking iron, recovery to baseline was longer than 168 days (IQR, 128->168). Median time to recovery to baseline in the higher-ferritin group taking iron was 107 days (IQR, 75-141), and for participants not taking iron, recovery to baseline was longer than 168 days (IQR, >168->168). Recovery of iron stores in all participants who received supplements took a median of 76 days (IQR, 20-126); for participants not taking iron, median recovery time was longer than 168 days (IQR, 147->168 days; P < .001). Without iron supplements, 67% of participants did not recover iron stores by 168 days.

CONCLUSIONS AND RELEVANCE

Among blood donors with normal hemoglobin levels, low-dose iron supplementation, compared with no supplementation, reduced time to 80% recovery of the postdonation decrease in hemoglobin concentration in donors with low ferritin (≤26 ng/mL) or higher ferritin (>26 ng/mL).

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01555060.

The health implications of low hemoglobin deferral in infrequent blood donors

BACKGROUND

The causes of anemia in infrequent blood donors deferred for low hemoglobin (Hb) are not well known. We sought to assess this via surveys of infrequent, non-menstruating deferred blood donors at two institutions, BloodCenter of Wisconsin and Puget Sound Blood Center.

STUDY DESIGN AND METHODS

Men at least 18 years of age and women at least 50 years of age who were deferred for low Hb (≤12.5 g/dL), had not more than one donation in the year prior to deferral, and did not successfully donate in the 3 months after their deferral were surveyed.

RESULTS

The total response rate was 380 donors or 34% of those contacted. Of the respondents, 141 had sought medical advice about their low Hb. Of these, 90 were confirmed to have anemia and 13 reported serious disease requiring medical intervention, including mantle cell lymphoma, multiple myeloma, and gastrointestinal bleeding.

CONCLUSIONS

A small but concerning number of infrequent blood donors deferred for low Hb have an underlying illness that is severe and would benefit from medical attention. Donors deferred for low Hb who have a high risk for serious underlying illness should be provided targeted educational information advising them to seek additional medical care.

Blood donor iron status: are we bleeding them dry?

PURPOSE OF REVIEW

This review examines the recent research on the prevalence, determinants and importance of low iron in blood donors, and on the efforts to reduce or prevent iron depletion in donor populations.

RECENT FINDINGS

Female donors, especially younger women, are at highest risk for donation-induced low iron, but menopausal women and high-frequency donors of both sexes also face considerable risk for iron depletion. Predonation screening for hemoglobin contributes little information on donor iron status. Consumption of supplemental iron is helpful in preventing or reversing low iron, and waiting longer between donations also facilitates the recovery of the iron lost through donation.

SUMMARY

Although the impact of phlebotomy-related iron depletion on donor health requires better documentation, measures are available now that can be deployed on a targeted or standardized basis. Blood centers, regulators, and donors should continue to evaluate different approaches for addressing this problem, with the likely outcome that no single measure is optimal for maintaining adequate collections while safeguarding donor health.

The sex difference in haemoglobin levels in adults - mechanisms, causes, and consequences

Men and women have different mean haemoglobin levels in health in venous blood - women have mean levels approximately 12% lower than men. A similar sex-related difference in haemoglobin levels in adult animals is found in many species of mammals, birds and reptiles, indicating that it is an important physiological phenomenon. It is probably a direct effect of sex hormones, both oestrogen and androgens, on erythropoiesis. However, since there is no difference in erythropoietin levels between the sexes, this effect most likely takes place in the kidney, rather than in the bone marrow. Oestrogens dilate and androgens constrict the renal microvasculature: dilation and vasoconstriction in vessels below 300 μm in diameter respectively increase and decrease the haematocrit in blood in arterioles, capillaries and venules, altering the oxygen delivery per unit red cell mass, and providing a mechanism for varying the red cell mass without compensatory changes in erythropoiesis.

Low hemoglobin deferral in blood donors

Low hemoglobin deferral occurs in about 10% of attempted whole blood donations and commonly is a consequence of iron deficiency anemia. Pre-menopausal women often have iron deficiency anemia caused by menstruation and pregnancy and have low hemoglobin deferral on their first donation attempt. Frequent donors also develop iron deficiency and iron deficiency anemia because blood donation removes a large amount of iron from the donor and the 56-day minimum inter-donation interval for donors in the United States is not sufficient for recovery of hemoglobin and iron stores. Other causes for low hemoglobin deferral range from a medically insignificant deferral of a woman with hemoglobin between 12.0 and 12.4 g/dL, which is within the normal reference range but below the 12.5 g/dL needed to donate blood, to anemia caused by an unrecognized malignancy in a "healthy" individual attempting to donate blood. The diverse causes of anemia in blood donors make it difficult to provide accurate information to donors about the cause of their low hemoglobin deferral and complicate implementation of programs to prevent them by blood collecting agencies. This article reviews how hemoglobin is measured and the demographics and causes of low hemoglobin deferral in blood donors. It provides recommendations for how blood collection agencies can provide donors with accurate information about the cause of their deferral and discusses programs that can be implemented to decrease these deferrals in regular donors.

State-of-the-art dried blood spot analysis: an overview of recent advances and future trends

Dried blood spots have become a popular method in a variety of micro blood-sampling techniques in the life sciences sector, consequently competing with the field of conventional, invasive blood sampling by venepuncture. Dried blood spots are widely applied in numerous bioanalytical assays and have gained a significant role in the screening of inherited metabolic diseases, in PK and PD modeling; in the treatment and diagnosis of infectious diseases; and in therapeutic drug monitoring. Recent technological developments such as automation, online extraction, mass spectrometric direct analysis and also conventional dried blood spot bioanalysis, as well as future developments in dried blood spot bioanalysis are highlighted and presented in this article.

Hemato-critical issues in quantitative analysis of dried blood spots: challenges and solutions

Dried blood spot (DBS) sampling for quantitative determination of drugs in blood has entered the bioanalytical arena at a fast pace during the last decade, primarily owing to progress in analytical instrumentation. Despite the many advantages associated with this new sampling strategy, several issues remain, of which the hematocrit issue is undoubtedly the most widely discussed challenge, since strongly deviating hematocrit values may significantly impact DBS-based quantitation. In this review, an overview is given of the different aspects of the ‘hematocrit problem’ in quantitative DBS analysis. The different strategies that try to cope with this problem are discussed, along with their potential and limitations. Implementation of some of these strategies in practice may help to overcome this important hurdle in DBS assays, further allowing DBS to become an established part of routine quantitative bioanalysis.

Iron status and dietary iron intake of female blood donors

BACKGROUND

The aim was to assess iron status and dietary iron intake in a sample of premenopausal female regular and new blood donors.

STUDY DESIGN AND METHODS

Premenopausal women blood donors were invited to participate. Blood samples were analyzed for serum ferritin and hemoglobin. An iron checklist assessed dietary iron intake. Donors were classified as regular donors or new donors.

RESULTS

Twenty-one new donors (mean [SD] age, 28.6 [6.0] years; body mass index [BMI], 25.6 [4.5] kg/m(2) ) and 172 regular donors (mean age, 29.4 [5.5] years; BMI, 24.7 [3.8] kg/m(2) ) participated. Fifty percent of regular donors and 24% of new donors had depleted iron stores (serum ferritin <15 μg/L; difference p = 0.036). Dietary iron intake was higher in regular donors (mean [SE], 12.6 [0.7] mg/day) compared to new donors (9.9 [0.4] mg/day; p = 0.006). Eighty-five percent of regular donors and 79% of new donors met the estimated average requirement for iron.

CONCLUSIONS

Despite the fact that most of these donors had an adequate dietary iron intake, more than half of the blood donors had depleted iron stores. Increasing dietary iron intake through supplements and/or dietary means is expected to be necessary to maintain adequate iron status in this group.

Iron deficiency anemia: a common and curable disease

Iron deficiency anemia arises when the balance of iron intake, iron stores, and the body's loss of iron are insufficient to fully support production of erythrocytes. Iron deficiency anemia rarely causes death, but the impact on human health is significant. In the developed world, this disease is easily identified and treated, but frequently overlooked by physicians. In contrast, it is a health problem that affects major portions of the population in underdeveloped countries. Overall, the prevention and successful treatment for iron deficiency anemia remains woefully insufficient worldwide, especially among underprivileged women and children. Here, clinical and laboratory features of the disease are discussed, and then focus is placed on relevant economic, environmental, infectious, and genetic factors that converge among global populations.

Evaluation of the validity of a rapid method for measuring high and low haemoglobin levels in whole blood donors

BACKGROUND

Haemoglobin screening methods need to be highly sensitive to detect both low and high haemoglobin levels and avoid unnecessary rejection of potential blood donors. The aim of this study was to evaluate the accuracy of measurements by HemoCue in blood donors.

MATERIALS AND METHODS

Three hundred and fourteen randomly selected, prospective blood donors were studied. Single fingerstick blood samples were obtained to determine the donors' haemoglobin levels by HemoCue, while venous blood samples were drawn for measurement of the haemoglobin level by both HemoCue and an automated haematology analyser as the reference method. The sensitivity, specificity, predictive values and correlation between the reference method and HemoCue were assessed. Cases with a haemoglobin concentration in the range of 12.5-17.9 g/dL were accepted for blood donation.

RESULTS

Analysis of paired results showed that haemoglobin levels measured by HemoCue were higher than those measured by the reference method. There was a significant correlation between the reference method and HemoCue for haemoglobin levels less than 12.5 g/dL. The correlation was less strong for increasing haemoglobin levels. Linear correlation was poor for haemoglobin levels over 18 g/dL. Thirteen percent of donors, who had haemoglobin levels close to the upper limit, were unnecessarily rejected.

DISCUSSION

HemoCue is suitable for screening for anaemia in blood donors. Most donors at Yazd are males and a significant percentage of them have haemoglobin values close to the upper limit for acceptance as a blood donor; since these subjects could be unnecessarily rejected on the basis of HemoCue results and testing with this method is expensive, it is recommended that qualitative methods are used for primary screening and accurate quantitative methods used in clinically suspicious cases or when qualitative methods fail.

The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II): twenty years of research to advance blood product safety and availability

The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989 to 2001, and the REDS-II, conducted from 2004 to 2012, were National Heart, Lung, and Blood Institute-funded, multicenter programs focused on improving blood safety and availability in the United States. The REDS-II also included international study sites in Brazil and China. The 3 major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as xenotropic murine leukemia virus-related virus. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of human immunodeficiency virus, human T-lymphotropic virus 1/2, hepatitis C virus, hepatitis B virus, West Nile virus, cytomegalovirus, human herpesvirus 8, parvovirus B19, malaria, Creutzfeldt-Jakob disease, influenza, and Trypanosoma cruzi infections. Other analyses have characterized blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors' perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, 2 large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these 2 REDS programs. In 2011, a new 7-year program, the Recipient Epidemiology and Donor Evaluation Study-III, was launched. The Recipient Epidemiology and Donor Evaluation Study-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting and adds a third country, South Africa, to the international program.

Validation and implementation of a new hemoglobinometer for donor screening at Canadian Blood Services

BACKGROUND

Hemoglobin (Hgb) determination is an essential part of donor qualification. We assessed and implemented a new spectrophotometer for donor Hgb determination.

STUDY DESIGN AND METHODS

Precision, accuracy, and ease of use were assessed on a prototype DiaSpect analyzer (DiaSpect Medical, GmBH, Sailauf, Germany). A protocol to qualify the analyzer was developed and executed preimplementation. Samples were developed for periodic quality control (QC). Postimplementation performance was assessed based on QC results and trending of deferral rates.

RESULTS

Precision was excellent, with a coefficient of variation of 0.53%-1.14% per sample. The correlation coefficient between capillary DiaSpect and venous laboratory autoanalyzer measurements was 0.736. After 169 out of 223 analyzers failed to qualify on our initial protocol, all were successfully qualified with the use of a modified protocol, adjusted to avoid sources of variability. Because commercial controls proved inadequate, in-house samples were developed for periodic QC. Postimplementation, all analyzers had adequate QC results. Deferral rates decreased from 10.1 to 8.1% (p < 0.0001) for female donors and from 0.8 to 0.6% for male donors (p < 0.0001). The system was faster and easier to use compared with our previous two-step process.

CONCLUSION

We successfully implemented a new spectrophotometer, which resulted in greater efficiency, improved ease of use, and decreased deferrals.

Population-based screening for anemia using first-time blood donors

Anemia is an important public health concern. Data from population-based surveys such as the National Health and Nutrition Examination Survey (NHANES) are the gold standard, but are obtained infrequently and include only small samples from certain minority groups. We assessed whether readily available databases of blood donor hemoglobin values could be used as a surrogate for population hemoglobin values from NHANES. Blood donor venous and fingerstick hemoglobin values were compared to 10,254 NHANES 2005-2008 venous hemoglobin values using demographically stratified analyses and ANOVA. Fingerstick hemoglobins or hematocrits were converted to venous hemoglobin estimates using regression analysis. Venous hemoglobin values from 1,609 first time donors correlated extremely well with NHANES data across different ages, genders, and demographic groups. Cigarette smoking increased hemoglobin by 0.26-0.59 g/dL depending on the intensity. Converted fingerstick hemoglobin from 36,793 first time donors agreed well with NHANES hemoglobin (weighted mean hemoglobin of 15.53 g/dL for donors and 15.73 g/dL for NHANES) with similar variation in mean hemoglobin by age. However, compared to NHANES, the larger donor data set showed reduced differences in mean hemoglobin between Blacks and other races/ethnicities. Overall, first-time donor fingerstick hemoglobins approximate US population data and represent a readily available public health resource for ongoing anemia surveillance.