Haematological values from a Gambian cohort--possible reference range for a West African population

Colonization of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci and its associated factors in cancer patients at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia

BACKGROUND

Cancer patients are predisposed to methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci colonization. However, the prevalence of these pathogens among cancer cases in Northwestern Ethiopia remains underreported.

OBJECTIVE

To determine the prevalence of colonization of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci and associated factors among cancer patients at the University of Gondar Comprehensive Specialized Hospital, Northwestern Ethiopia.

METHOD

A cross-sectional study enrolled 288 confirmed cancer participants through stratified systematic random sampling, gathering socio-demographic and clinical data via pretested structured questionnaires from May 1 to July 30, 2023. Each participant provided two specimens: a nasal swab and a fecal sample. Nasal swabs were collected using sterile swabs, inserted at least 1 cm into each nostril, and rotated against the nasal membrane for 10 to 15 seconds, which were then placed in Amies transport medium. Fecal specimens were collected in leak-proof plastic containers, swabbed, and transferred to Cary Blair transport medium. Nasal swabs and fecal specimens were cultured on Mannitol salt agar at 37°C for Staphylococcus aureus identification, which was confirmed by coagulase testing and Gram staining. Enterococci were cultured on Bile esculin agar at 43°C and identified at the genus level by cultural characteristics, with confirmation through Gram reaction and catalase tests. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk diffusion method, with minimum inhibitory concentrations for vancomycin determined via E-test strips. To detect methicillin-resistant Staphylococcus aureus, a cefoxitin disk was used. Inducible clindamycin resistance in Staphylococcus aureus was determined by the D test. Epi-info version 7 and SPSS version 27 were used for data entry and data analysis, respectively. The Pearson Chi-Square test was initially used to evaluate the association between factors and outcomes as the preliminary analysis, with a significance threshold of p <  0.05. Variables meeting this criterion underwent bivariable and multivariable logistic regression analyses, using p-value cutoffs of <  0.2 for bivariable and <  0.05 for multivariable analyses.

RESULT

The study involved 288 participants, with 51.0% being men and a mean age of 45.6 years. The prevalence of methicillin-resistant Staphylococcus aureus was 11.1% (95% CI: 7.5-14.7%), while vancomycin-resistant Enterococci had a prevalence of 2.8% (95% CI: 0.9-4.7%). Inducible clindamycin-resistant Staphylococcus aureus comprised 13.5% of the isolates. The multidrug-resistant proportion of Staphylococcus aureus and Enterococci were 56.2% and 55.2%, respectively. Both organisms exhibited the highest resistance to the antibiotic classes of penicillin and tetracycline. Significant associations were identified between methicillin-resistant Staphylococcus aureus colonization and low absolute neutrophil count (AOR =  13.050, 95% CI: 1.362-125.00, P =  0.026), and between vancomycin-resistant Enterococci colonization and having undergone an invasive procedure (AOR =  8.648, 95% CI: 1.870-39.992, P =  0.006).

CONCLUSION

The study reveals a significant prevalence of methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci colonization among cancer patients, raising public health concerns. High antibiotic resistance rates complicate treatment and may impact patient outcomes. Notably, the high inducible clindamycin resistance report, highlights the need for D-testing. Screening for methicillin-resistant Staphylococcus aureus is recommended as an important antibiotic stewardship measure, while early detection of vancomycin-resistant Enterococci colonization is crucial to reduce complications.

Factors influencing malnutrition among adolescent girls in The Gambia: a mixed-methods exploratory study

BACKGROUND

In The Gambia, existing research to understand and address malnutrition among adolescent girls is limited. Prior to the conduct of large-scale studies, formative research is needed. The aim of this mixed methods, cross-sectional study was to explore cultural contexts relevant to nutritional status, feasibility and appropriateness of recruitment and data collection methods (questionnaires and anthropometric measures), and plausibility of data collected.

METHODS

The study took place in May-June 2021 in an urban conurbation in Brikama local government area (LGA) and two rural villages in Mansakonko LGA, The Gambia. The purposive sampling frame of the all-female sample included residence in the selected urban or rural settings and being aged 10-14 or 15-19 years. Thirty-two girls aged 10 to 19 years, with equal numbers in urban and rural settings were recruited. Four focus groups discussions (FGDs), with eight participants in each, were held to understand perspectives on cultural practices; concepts of under- and overweight, and research recruitment methods. The same participants completed questionnaires on socioeconomic circumstances, health, access to community resources, nutrition knowledge, sleep, and physical activity, and had anthropometric measures taken. FGDs were then reconvened to discuss the feasibility and acceptability of the questionnaires and anthropometric measures, and views on providing biological samples in the future. FGD data were analysed using thematic analysis. Body mass index (BMI)-for-age and height-for-age z-scores, mid-upper arm circumference, and waist: hip ratios were assessed and descriptive statistics used to explore the data obtained.

RESULTS

Five themes were identified in the focus group discussions: 1. Cultural norms: harmful vs. beneficial to nutrition-related health; 2. Concepts of healthy diet and weight; 3. Approaches to tackling under- and overnutrition; 4. Study recruitment: barriers and facilitators; 5. Study questionnaires and proposed measures are mostly feasible and acceptable. Questionnaire data highlighted limited access to resources (e.g. food markets and electricity) as important individual, household and community factors influencing malnutrition in rural settings. The anthropometric measures reflected the double burden of malnutrition in The Gambia, with the presence of stunting (41%), underweight (31%), and living with overweight or obesity (10%). A higher proportion of participants were underweight in rural compared to urban settings (50% vs 12.5% respectively, p = 0.03). Over 70% of those classified as underweight perceived their weight as normal.

CONCLUSION

This exploratory study provides novel data to inform larger-scale research to understand and address malnutrition among adolescent females in The Gambia. Urban-rural variance in the double burden of malnutrition, factors influencing malnutrition, and in the barriers to and facilitators of adolescents taking part in research, are key considerations.

Seasonal variations in haematological and biochemical parameters of healthy Gambian adults: Retrospective study 2018-2022

The objectives of this study were to determine the presence and effect of seasonal variations and provide insights into trend from 2018 to 2022 in a comprehensive set of routine haematological indices and biochemical measurements in Gambian adults with no known underlying health condition. We retrieved five years of data from an electronic database and analysed 493 full blood counts and 643 biochemical data from different individuals. In this study, we focused on data from individuals with no known underlying health condition who visited the clinical diagnostic laboratory for routine medical examinations or assessments.Our study found a positive association between seasonality (wet season as the reference) and Hb (HB: 0.014(0.015), P<0.05), White blood cells (WBC) (WBC: 0.243(0.163), p = 0.0014), and neutrophils (neutrophils: 0.271(0.131), P<0.05) with exception to red blood cells (RBC) (RBC: - 0.184(0.061), P< 0.003) that showed negative association. Despite the association, the seasonal effects on our derived reference intervals for haematological indices and biochemical measurements from wet season to dry season were not statistically significant (P>0.05). In addition, we observed in our heatmap result that some laboratory parameters, including HB, RBC, haematocrit (HCT), urea, liver enzymes, and potassium, showed seasonal variation patterns throughout the year, with median levels being normal to slightly low during the dry season and normal to high during the wet season. We also found no significant difference (P>0.05) among the median values for all parameters from 2018 to 2022. Additionally, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) parameters showed a consistent declining trend from 2018 to 2022. Our study found no seasonal effects on the derived reference intervals of haematological indices and biochemical measurements. However, we observed changes in patterns for certain parameters particularly HB, RBC, liver enzymes, and potassium based on seasonality.

Establishing reference intervals for common hematology test parameters from apparently healthy geriatrics in Asella town, Southeast Ethiopia, 2020: a community-based cross-sectional study

Background

Reference intervals are an important method tool for identifying abnormal laboratory test results. Complete blood count reference values are useful to interpret complete blood count (CBC) results and make clinical decisions, but these values have not been established for geriatrics in Asella town. Therefore, this study aimed to establish reference intervals (RIs) for complete blood count (CBC) parameters from geriatric participants/subjects in Asella town, Southeast Ethiopia.

Methods

A community-based cross-sectional study was conducted from December 2019 to May 2020. An interviewer-administered questionnaire was used to collect data on sociodemography and other characteristics from 342 eligible geriatric participants. Weight, height, and vital signs were measured, and 8 mL of blood sample was collected. Screening tests such as HIV, HBsAg, HCV, syphilis, stool examination, and urinalysis were performed. The hematological parameter was measured using a Sysmex kx-21 hematology analyzer. The data were analyzed using SPSS version 21 software. The non-parametric independent Kruskal-Wallis test and Wilcoxon rank-sum test (Mann-Whitney U test) were used to compare the parameters between age groups and genders. The 97.5 and 2.5th percentile were the upper and lower reference limit for the population.

Results

According to the study's findings, the reference intervals of red blood cell, white blood cell, platelet count, hemoglobin (HGB), and hematocrit (HCT) in male geriatrics were 3.8-5.85 × 1012/L, 3.1-9.66 × 109/L, 115.8-353 × 109/L, 12.4-17.76 g/dL, and 35.06-50.2%, respectively. The respective values for women were 3.94-5.48 × 1012/L, 3.13-8.4 × 109/L, 137.5-406 × 109/L, 12.5-16.4 g/dL, and 36.09-48.2%. Most of the hematological parameters showed significant differences between the two genders (p value <0.05).

Conclusion

Accurate gender and age-specific reference intervals are crucial in managing patient health. The current study offers essential CBC hematological parameters that can assist clinicians in interpreting laboratory results and can improve healthcare quality in the geriatric population. Therefore, it is more relevant to use the current RIs in the geriatric set-up.

Adult and paediatric haematology and clinical chemistry laboratory reference limits for Liberia

Background

As more research is conducted in Liberia, there is a need for laboratory reference limits for common chemistry and haematology values based on a healthy population. Reference limits from the United States may not be applicable.

Objective

The aim of this study was to present laboratory reference ranges from a Liberian population and compare them to United States ranges.

Methods

Serum chemistry and haematology values from 2529 adults and 694 children and adolescents obtained from two studies conducted in Liberia between 2015 to 2017 were used to determine reference limits. After removing outliers, the reference limits defined by the 2.5th and 97.5th percentiles were determined by sex in three age groups (6–11, 12–17, and 18+ years).

Results

The median (interquartile range) of adults was 29 (23, 37) years; 44% were female. The median (interquartile range) for children and adolescents was 12 (9, 15) years; 53% were female. Several reference ranges determined using Liberian participants differed from those in the US. For chemistries, a high percentage of both adults and children/adolescents had high serum chloride levels based on United States ranges. For haematology, a high percentage of Liberian participants had haemoglobin and related assays below the lower limit of United States ranges.

Conclusion

Chemistry and haematology reference intervals determined for a Liberian population of healthy individuals should be considered for establishing eligibility criteria and monitoring of laboratory adverse events for clinical trials as well as for use in clinical settings in Liberia and perhaps for other countries in Western Africa.

Next-generation reference intervals for pediatric hematology

Background Interpreting hematology analytes in children is challenging due to the extensive changes in hematopoiesis that accompany physiological development and lead to pronounced sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, and limitations in current approaches to laboratory test result displays restrict their use when guiding clinical decisions. Methods We employed an improved data-driven approach to create percentile charts from laboratory data collected during patient care in 10 German centers (9,576,910 samples from 358,292 patients, 412,905-1,278,987 samples per analyte). We demonstrate visualization of hematology test results using percentile charts and z-scores (www.pedref.org/hematology) and assess the potential of percentiles and z-scores to support diagnosis of different hematological diseases. Results We created percentile charts for hemoglobin, hematocrit, red cell indices, red cell count, red cell distribution width, white cell count and platelet count in girls and boys from birth to 18 years of age. Comparison of pediatricians evaluating complex clinical scenarios using percentile charts versus conventional/tabular representations shows that percentile charts can enhance physician assessment in selected example cases. Age-specific percentiles and z-scores, compared with absolute test results, improve the identification of children with blood count abnormalities and the discrimination between different hematological diseases. Conclusions The provided reference intervals enable precise assessment of pediatric hematology test results. Representation of test results using percentiles and z-scores facilitates their interpretation and demonstrates the potential of digital approaches to improve clinical decision-making.

Comparison of Lymphocyte Subset Populations in Children From South Africa, US and Europe

Background: Typically, African healthcare providers use immunological reference intervals adopted from Europe and the United States (US). This may be inappropriate in a setting with many differences including exposure to different environmental stimuli and pathogens. We compared immunological reference intervals for children from Europe and the US with South African children to explore whether healthy children living in settings with high rates of infectious diseases have different baseline immunological parameters. Methodology: Blood was taken from 381 HIV-uninfected children aged between 2 weeks and 13 years of age from a Child Wellness Clinic in an informal settlement in Cape Town to establish local hematological and lymphocyte reference intervals for South African children. Flow-cytometry quantified percentage and absolute counts of the B-cells, NK-cells, and T-cells including activated, naïve, and memory subsets. These parameters were compared to three separate studies of healthy children in Europe and the US. Results: Increased activated T-cells, and natural killer cells were seen in the younger age-groups. The main finding across all age-groups was that the ratio of naïve/memory CD4 and CD8 T-cells reached a 1:1 ratio around the first decade of life in healthy South African children, far earlier than in resource-rich countries, where it occurs around the fourth decade of life. Conclusions: This is the largest data set to date describing healthy children from an African environment. These data have been used to create local reference intervals for South African children. The dramatic decline in the naïve/memory ratio of both CD4 and CD8 T-cells alongside increased activation markers may indicate that South African children are exposed to a wider range of environmental pathogens in early life than in resource-rich countries. These marked differences illustrate that reference intervals should be relevant to the population they serve. The implications for the developing pediatric immune system requires further investigation.

Haematological values in a healthy adult population in Yaoundé, Cameroon

Background

Haematological values derived from local populations are useful in laboratories to improve diagnoses for local patients. In Cameroon, these data are not yet available. Moreover, there is great variation in baseline parameters pertaining to full blood cell count among medical laboratories.

Objectives

This study aimed to determine values for the complete blood cell count of a healthy adult Cameroonian population for use in locally derived ranges in our medical laboratories.

Methods

A cross-sectional study was conducted among blood donors attending three blood banks in Yaoundé from November 2015 to September 2016. We expected to obtain at least 120 venous blood samples from both men and women. Tests were performed for (1) HIV, (2) complete blood cell count, (3) hepatitis B virus, (4) malaria, (5) syphilis, (6) C-reactive protein and (7) hepatitis C virus.

Results

We enrolled 294 healthy participants (161 men, 133 women) aged 18 to 55 years. The median haemoglobin concentration was 135 g/L in men and 114 g/L in women (p < 0.001). The median reticulocyte count was 60 × 10⁹/L in men and 40 × 10⁹/L in women (p < 0.001). Significant variation by sex was observed for the platelet count. The median white blood cell count was 4.1 × 10⁹/L in men and 4.6 × 10⁹/L in women (p = 0.008).

Conclusion

This study provides locally derived ranges for complete blood cell and reticulocyte counts for a healthy adult population in Yaoundé, Cameroon. These results can be used pending larger studies.

Reference values for blood count laboratory tests in the Brazilian adult population, National Health Survey

OBJECTIVE

To describe reference values for blood counts obtained from laboratory tests in the Brazilian adult population according to laboratory results from the National Health Survey (Pesquisa Nacional de Saúde - PNS), by gender, age group and skin color.

METHODS

The initial sample consisted of 8,952 adults. To determine the reference values, individuals with prior diseases and outliers were excluded. Mean values, standard deviation and limits were stratified by gender, age group and skin color.

RESULTS

For red blood cells, men presented a mean value of 5.0 million per mm3 (limits: 4.3-5.8) and women, 4.5 million per mm3 (limits: 3.9-5.1). Hemoglobin levels were higher among men with a mean of 14.9 g/dL (13.0-16.9), and in women, 13.2 g/dL (11.5-14.9). The mean number of white blood cells among men was 6.142/mm3 (2.843-9.440) and 6.426/mm3 (2.883-9.969) for women. Other parameters showed close values between the genders. Regarding age groups and skin color, mean values, standard deviation and limits of the exams presented small variations.

CONCLUSION

Hematological reference values based on the national survey allow for the establishment of specific reference limits for gender, age and skin color. The results presented here may contribute to the establishment of better evidence and criteria for the care, diagnosis and treatment of diseases.

Modelling pathogen load dynamics to elucidate mechanistic determinants of host-Plasmodium falciparum interactions

During infection, increasing pathogen load stimulates both protective and harmful aspects of the host response. The dynamics of this interaction are hard to quantify in humans, but doing so could improve understanding of mechanisms of disease and protection. We sought to model the contributions of parasite multiplication rate and host response to observed parasite load in individual subjects with Plasmodium falciparum malaria, using only data obtained at the time of clinical presentation, and then to identify their mechanistic correlates. We predicted higher parasite multiplication rates and lower host responsiveness in severe malaria cases, with severe anemia being more insidious than cerebral malaria. We predicted that parasite growth-inhibition was associated with platelet consumption, lower expression of CXCL10 and type-1 interferon-associated genes, but increased cathepsin G and matrix metallopeptidase 9 expression. We found that cathepsin G and matrix metallopeptidase 9 directly inhibit parasite invasion into erythrocytes. Parasite multiplication rate was associated with host iron availability and higher complement factor H levels, lower expression of gametocyte-associated genes but higher expression of translation-associated genes in the parasite. Our findings demonstrate the potential of using explicit modelling of pathogen load dynamics to deepen understanding of host-pathogen interactions and identify mechanistic correlates of protection.

Variation in hemoglobin across the life cycle and between males and females

WHO recommendations for hemoglobin (Hb) cutoffs to define anemia are based on a handful of studies conducted in the 1960s that did not include participants from all life stages. To evaluate whether there is a need to update Hb cutoffs, we conducted a narrative review of the literature to identify more recent studies that have reported Hb cutoffs in males and females in various life stages. We compiled information from 60 studies conducted around the globe between 1975 and 2018. Many studies reported cutoffs that were similar to WHO recommendations, but cutoffs identified in studies of infants, young children, premenopausal women, and the elderly tended to be lower than WHO recommendations, while cutoffs identified in studies of men tended to be higher than WHO cutoffs. Few studies excluded individuals with iron deficiency or inflammation, which limits the conclusions that can be drawn regarding normal reference ranges. Further research using more stringent exclusion criteria is needed to develop revised recommendations for Hb cutoffs to define anemia.

Determination of Haematological Reference Ranges in Healthy Adults in Three Regions in Ghana

Laboratory results interpretation for diagnostic accuracy and clinical decision-making in this period of evidence-based medicine requires cut-off values or reference ranges that are reflective of the geographical area where the individual resides. Several studies have shown significant differences between and within populations, emphasizing the need for population-specific reference ranges. This cross-sectional experimental study sought to establish the haematological reference values in apparently healthy individuals in three regions in Ghana. Study sites included Nkenkaasu, Winneba, and Nadowli in the Ashanti, Central, and Upper West regions of Ghana, respectively. A total of 488 healthy participants were recruited using the Clinical and Laboratory Standards Institute (United States National Consensus Committee on Laboratory Standards, NCCLS) Guidance Document C28A2. Medians for haematological parameters were calculated and reference values determined at 2.5th and 97.5th percentiles and compared with Caucasian values adopted by our laboratory as reference ranges and values from other African and Western countries. RBC count, haemoglobin, and haematocrit (HCT) were significantly higher in males compared to females. There were significant intraregional and interregional as well as international variations of haematological reference ranges in the populations studied. We conclude that, for each geographical area, there is a need to establish geography-specific reference ranges if accurate diagnosis and concise clinical decisions are to be made.

Baseline haematological and biochemical reference values for healthy male adults from Mali

INTRODUCTION

Haematological reference values are very important for diagnostic orientation and treatment decision. The aim of this study was to establish haematological reference values for Malian healthy adults.

METHODS

A cross-sectional study including 161 male Malians aged between 19 and 54 years old was performed. Median and reference ranges were calculated for haematological and biochemical parameters. Parametric student's t-test was used to determine any statistically significant differences by age, smoker status, body mass index (BMI) and occupation. Ranges were further compared with those reported for other African, Afro-American and Caucasian populations.

RESULTS

Increased levels of MCV, MCH, PLT and EOS were found in younger Malians who had abnormal BMI and altered platelets parameters. Notably, significantly lower eosinophil and monocyte counts were observed in Malians compared to Europeans The smoking status did not seem to directly affect RIs.

CONCLUSION

This is the first study to determine normal laboratory parameters in Malian adult males. Our results underscore the necessity of establishing region-specific clinical reference ranges that would allow clinicians and practitioners to manage laboratory tests, diagnosis and therapies. These data are useful not only for the management of patients in Mali, but also to support European and American clinicians in the health management of asylum seekers and migrants from Mali.

Establishing Reference Ranges of Hematological Parameters from Malian Healthy Adults

INTRODUCTION

Measurement of immuno-hematological parameters has been historically helpful in the diagnosis and treatment monitoring of many infectious diseases and cancers. However, these parameters have not yet been established in many developing countries where patient care strongly relies on such low-cost tests. This study describes the immuno-hematological parameter ranges for Malian healthy adults.

METHODS

A cross sectional study was conducted from August 2004 to May 2013. We included 213 healthy volunteers (173 male and 40 female), aged between 18-59 years. Median, 2.5 and 97.5 percentile ranges for each immuno-hematological parameter are presented.

RESULTS

In our study population, the hematological parameters' ranges were mostly different to the universal established ranges. We found in our population a Median white blood cell (WBC) count of 5200 cells/μL [3237.5-11900], Red Blood Cell (RBC) count of 4.94 10^6 [3.56-6.17], hemoglobin (Hb) of 14.2 g/dL [12.2-17.38], platelet count (Plt) of 275 10^3/μL [145.4-614.4], lymphocytes 2050/μL [1200-3800], neutrophils 2200/μL [1040-6220]; monocytes 200/μL [100-660]; eosinophils 131/μL [0-1026]; CD4 902 cells/μL [444-1669] and CD8 485 cells/μL [0-1272]. We found significant gender differences in RBC, Hb level and MPV. However, RBC and Hb were higher in males median values compared to females (median values) (p<0.001), whereas the Mean platelet volume lower values (MPV) in males than females (P<0.047). The hemoglobin level for some West African countries (Mali, Burkina Faso, Togo, and Nigeria) ranged from 13.5 to 15.1 g/dL for males and 12 to 13 g/dL for females. However in East and Southern Africa, the values were anywhere from 14.1 to 16.1 for males and 11.2 to 14.4 for females.

CONCLUSION

Our data may help physicians to better define hematological abnormalities in patients. They may also be used to define new "normal hematological values" in Malian population or in the whole West African population.

Hematological reference intervals determination in adults at Gondar university hospital, Northwest Ethiopia

Background

Hematological reference values are important for the clinical decisions in laboratory diagnosis and monitoring of patients. The correct interpretation of laboratory results depends entirely on the reference intervals that have been established for the locality. But, in sub-Saharan African countries particularly in Ethiopia, locally derived reference intervals were not established and they are forced to use intervals established from western population. Thus this study aimed to establish locally derived hematological reference values that could be used in Northwest Ethiopia.

Methods

A cross sectional study was conducted from April to May 2014 with 120 male and 120 female apparently health adult blood donors at Gondar University Hospital. A structured pretested questionnaire was used for socio demographic and clinical data collection. About 4 ml of blood was collected with EDTA test tube and analyzed using Cell-Dyn 1800 to enumerate the hematological parameters. The data were collected and entered into SPSS version 20 for analysis. Mann–Whitney U test was used to determine reference intervals and Harris and Boyd test was used to determine the reference intervals that need partition. The 95th percentile of measurements was taken as a reference interval.

Results

Median and 95th percentile of WBC for general population were lower than Caucasian population, Addis Ababa, Burkina Faso and Kenya of similar studies. The RBC, Hgb and PCV lower 95% limit values of both sex were lower than studies in Addis Ababa, Kenya, Burkina Faso and text book. While PCV upper limit values higher than the above countries. MCV values of the current study were higher than those countries while MCHC values were lower. Similarly, the absolute values of neutrophils in the current study were lower than Caucasian and Afro Caribbean but higher than African countries and Jamaica but lymphocyte count was higher.

Conclusions

The hematological reference intervals established in this study was different from those reported in other part of Ethiopia or African countries as well as Caucasian population. The RBC, PCV, Hgb and MCHC reference intervals were different in gender. Thus, using of locally determined reference range is advisable.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2288-8) contains supplementary material, which is available to authorized users.

Hematological Indices in Malian Children Change Significantly During a Malaria Season and with Increasing Age: Implications for Malaria Epidemiological Studies

Standard hematological indices are commonly used in malaria epidemiological studies to measure anemia prevalence and calculate blood parasite densities. In Africa, few studies have investigated how these indices change during a malaria transmission season and with increasing age. To address these knowledge gaps, we collected blood from 169 healthy Malian children aged 3-12 years before (May 2010) and after (January 2011) a transmission season. Red blood cell (RBC) count, hemoglobin (Hb) level, hematocrit (Ht), white blood cell (WBC) count, and WBC subsets were measured in paired blood samples, and the data were stratified by month (May, January) and age group (3-5, 6-8, and 9-12 years). From May to January, RBC count (4.53-4.70 × 10(6)/μL; P < 0.0001), Hb level (11.5-11.9 g/dL; P < 0.0001), and Ht (37.1-39.2%; P < 0.0001) increased, and WBC count (6.46-5.96 × 10(3)/μL; P = 0.0006) decreased. From May to January, the prevalence of WBC subsets also changed: 35-43% neutrophils, 6.5-7.6% monocytes, and 53-45% lymphocytes (P < 0.001). These seasonal changes were not associated with the number of malaria episodes experienced in the interim or the presence of RBC polymorphisms. In May, Hb (11.2, 11.4, and 11.8 g/dL; P = 0.0013) and Ht (36.5%, 36.7%, and 38.1%; P = 0.0154) increased and WBC count (8.04, 6.43, and 5.76 × 10(3)/μL; P < 0.0001) decreased with age group; similar differences were observed in January. These data suggest that season- and age-based reference values for hematological indices are needed to better estimate anemia prevalence and parasite density in malaria epidemiological studies.

Seasonal variation in haematological and biochemical reference values for healthy young children in The Gambia

Background

Haematological and biochemistry reference values for children are important for interpreting clinical and research results however, differences in demography and environment poses a challenge when comparing results. The study defines reference intervals for haematological and biochemistry parameters and examines the effect of seasonality in malaria transmission.

Methods

Blood samples collected from clinically healthy children, aged 12–59 months, in two surveys during the dry and wet season in the Upper River region of The Gambia were processed and the data analysed to generate reference intervals based on the 2.5^th and 97.5^th percentiles of the data.

Results

Analysis was based on data from 1141 children with median age of 32 months. The mean values for the total white cell count and differentials; lymphocyte, monocyte and neutrophil decreased with increasing age, were lower in males and higher in the wet season survey. However, platelet values declined with age (p < 0.0001). There was no evidence of effect of gender on mean values of AST, ALT, lymphocytes, monocytes, platelets and haemoglobin.

Conclusion

Mean estimates for haematological and biochemistry reference intervals are affected by age and seasonality in the first five years of life. This consistency is important for harmonisation of reference values for clinical care and interpretation of trial results.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-016-0545-6) contains supplementary material, which is available to authorized users.

Complete blood count reference intervals for healthy Han Chinese adults

BACKGROUND

Complete blood count (CBC) reference intervals are important to diagnose diseases, screen blood donors, and assess overall health. However, current reference intervals established by older instruments and technologies and those from American and European populations are not suitable for Chinese samples due to ethnic, dietary, and lifestyle differences. The aim of this multicenter collaborative study was to establish CBC reference intervals for healthy Han Chinese adults.

METHODS

A total of 4,642 healthy individuals (2,136 males and 2,506 females) were recruited from six clinical centers in China (Shenyang, Beijing, Shanghai, Guangzhou, Chengdu, and Xi'an). Blood samples collected in K2EDTA anticoagulant tubes were analyzed. Analysis of variance was performed to determine differences in consensus intervals according to the use of data from the combined sample and selected samples.

RESULTS

Median and mean platelet counts from the Chengdu center were significantly lower than those from other centers. Red blood cell count (RBC), hemoglobin (HGB), and hematocrit (HCT) values were higher in males than in females at all ages. Other CBC parameters showed no significant instrument-, region-, age-, or sex-dependent difference. Thalassemia carriers were found to affect the lower or upper limit of different RBC profiles.

CONCLUSION

We were able to establish consensus intervals for CBC parameters in healthy Han Chinese adults. RBC, HGB, and HCT intervals were established for each sex. The reference interval for platelets for the Chengdu center should be established independently.

Hematological and biochemical data obtained in rural northern Uganda

Reference intervals for common hematological and clinical chemistry parameters constitute an important basis for health care. Moreover, with increasing priority in drug and vaccine development for infectious diseases in Africa, the first priority is the safety evaluation and tolerability of the candidate interventions in healthy populations. To accurately assess health status and address adverse events, clinical reference intervals in the target population are necessary. We report on hematological and biochemical indices from healthy volunteers who participated in a clinical trial in Lira, northern Uganda. Median and nonparametric 95% percentiles on five hematology and 15 biochemistry analytes are shown. Although most hematological analytes conformed to reported reference intervals and trends in Africa, literature review from different African countries highlight the need for a region-specific children reference interval that can be appropriate for the population.

Biochemical and hematologic parameters for children in the middle belt of Ghana

Reference values derived from developed countries are used in many countries in Africa for interpretation of laboratory results obtained during routine healthcare and clinical trials. Use of locally derived reference values has been recommended. The purpose of the study was to establish age- and sex-specific reference values for children in the middle belt of Ghana. Reference values were determined for 21 biochemical and 18 hematologic parameters by using Clinical and Laboratory Standards Institute C28-A3 guidelines in a sample of 1,442 healthy children. Hemoglobin, hematocrit, mean cell volume, erythrocytes, urea, and creatinine were lower when compared with values from northern countries but alanine aminotransferase, aspartate aminotransferase, and total bilirubin were higher. A panel of locally relevant age- and sex-specific reference values was established for commonly used biochemical and hematologic tests in children in the middle part of Ghana. This will help in interpretation of laboratory results for clinical management of patients, screening, and safety monitoring during clinical trials.

Haematological and biochemical reference values of Gambian infants

OBJECTIVE

To establish haematological and biological reference values for Gambian infants.

METHODS

Basic haematological and biochemical indices were analysed in blood samples obtained from healthy infants from Sukuta in the Western Division of The Gambia. The 2.5 and the 97.5 centiles for these indices were estimated.

RESULTS

Reference ranges for haematological and biochemical indices were determined. Haemoglobin, total white cell count (WBC) and platelet levels decreased with age (P < 0.001), whereas most of the white cell count subsets except monocytes did not vary with age. Potassium and alkaline phosphatase fell significantly with increasing age (P < 0.001; P < 0.001), whereas urea and creatinine rose with increasing age (P = 0.002; P < 0.001, respectively).

CONCLUSION

Our set of haematological and biochemical reference values for healthy infants in The Gambia differs from values in other settings, thus underscoring the importance of establishing region-specific paediatric reference ranges to ensure optimal patient management and evaluate the impact of interventions in clinical research.

Investigation on reference intervals and regional differences of platelet indices in healthy Chinese Han adults

BACKGROUND

Reference intervals are important for interpretation of clinical laboratory tests. The platelet (PLT) indices such as the mean platelet volume (MPV) and platelet distribution width (PDW) are newer hematological parameters, which have been recently reported as clinically valuable biomarkers. However, there are not many studies that have estimated the reference intervals for these parameters in healthy Chinese Han adults.

OBJECTIVE

The objectives of this study were to establish reference values of PLT indices [including PLT count, MPV, PDW, platelet-large cell ratio (P-LCR), and plateletcrit (Pct)] for healthy Chinese Han adults. We also aimed to determine the region-based differences of PLT indices in China.

METHODS

A total of 4,642 volunteers with a mean age of 43 were recruited from six regions of China. PLT indices were performed on Sysmex XE-2100 hematology analyzers, whose traceability was well verified.

RESULTS

There were significant region-based differences for all PLT indices. Reference people in Chengdu had the lowest mean PLT count and Pct, but the highest MPV, PDW, and P-LCR among the six regions. Therefore, we derived the reference intervals in Chinese Han population excluding Chengdu reference people for PLT indices as PLT count: (127-341) × 10(9)/l; MPV: (9.20-13.30) fl; PDW: 9.90-19.00%; P-LCR: 18.10-52.00%; Pct: 16.00-41.00%.

CONCLUSIONS

Region-specific reference intervals are essential as there were statistically significant region-related differences in the PLT parameters. The reference intervals established in this study differed from the existing reference values. Chengdu region may need proper specific reference ranges, which apply to their people, for all PLT parameters.

Haemoglobin levels for population from Gambo, a rural area of Ethiopia, and their association with anaemia and malaria

BACKGROUND

Knowledge of appropriate reference intervals is critical not only to provide optimal clinical care, but also to enrol populations in medical research. The aim of this study was to generate normal ranges of laboratory values for haemoglobin among healthy Ethiopian adults and children and to determine if anaemia is a possible indicator of malaria in women and children in this area of Ethiopia.

METHODS

This study was carried out from January 2008 to May 2010. The reference sample population with malaria-negative consisted of 454 individuals, divided women, men and children. The malaria-infected sample population consisted of 117 individuals. The reference ranges were based on the guidelines from the Clinical and Laboratory Standards Institute. Haemoglobin concentration was determined by Hemo-Control EKF Diagnostic Analyser on whole blood. Testing for malaria-positive and negative infection was done by microscopy and by PCR.

RESULTS

The lower limits for adult haemoglobin range obtained from this population were slightly higher than those derived from other African populations, but were equal to those established by other studies in Ethiopia and the World Health Organization (WHO). Regarding children, the minimum values were lower than those obtained from different African populations and those established by WHO. The malaria-negative group had anaemia in 35.6% of cases and in the malaria-positive group in 70.9%. There was a stronger, statistically significant association between anaemia and malaria-positive samples than between anaemia and malaria-negative samples in women and both groups of children.

CONCLUSIONS

The results from this study are a contribution in the definition of the haemoglobin parameters in African populations, which could be taken as standards for interpretation of laboratory results. The haemoglobin indices in adults from Gambo tended to be higher than other African populations and in children were lower than other studies in Africa. The results also suggest that anaemia is not useful as a supportive diagnostic criterion to monitor and evaluate malaria in women and children from Ethiopia, because a 29.1% of malaria cases will be not detected, because of not having anaemia.

A phase I randomized clinical trial of candidate human immunodeficiency virus type 1 vaccine MVA.HIVA administered to Gambian infants

BACKGROUND

A vaccine to decrease transmission of human immunodeficiency virus type 1 (HIV-1) during breast-feeding would complement efforts to eliminate infant HIV-1 infection by antiretroviral therapy. Relative to adults, infants have distinct immune development, potentially high-risk of transmission when exposed to HIV-1 and rapid progression to AIDS when infected. To date, there have been only three published HIV-1 vaccine trials in infants.

TRIAL DESIGN

We conducted a randomized phase I clinical trial PedVacc 001 assessing the feasibility, safety and immunogenicity of a single dose of candidate vaccine MVA.HIVA administered intramuscularly to 20-week-old infants born to HIV-1-negative mothers in The Gambia.

METHODS

Infants were followed to 9 months of age with assessment of safety, immunogenicity and interference with Expanded Program on Immunization (EPI) vaccines. The trial is the first stage of developing more complex prime-boost vaccination strategies against breast milk transmission of HIV-1.

RESULTS

From March to October 2010, 48 infants (24 vaccine and 24 no-treatment) were enrolled with 100% retention. The MVA.HIVA vaccine was safe with no difference in adverse events between vaccinees and untreated infants. Two vaccine recipients (9%) and no controls had positive ex vivo interferon-γ ELISPOT assay responses. Antibody levels elicited to the EPI vaccines, which included diphtheria, tetanus, whole-cell pertussis, hepatitis B virus, Haemophilus influenzae type b and oral poliovirus, reached protective levels for the vast majority and were similar between the two arms.

CONCLUSIONS

A single low-dose of MVA.HIVA administered to 20-week-old infants in The Gambia was found to be safe and without interference with the induction of protective antibody levels by EPI vaccines, but did not alone induce sufficient HIV-1-specific responses. These data support the use of MVA carrying other transgenes as a boosting vector within more complex prime-boost vaccine strategies against transmission of HIV-1 and/or other infections in this age group.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00982579. The Pan African Clinical Trials Registry PACTR2008120000904116.

Prolonged neutrophil dysfunction after Plasmodium falciparum malaria is related to hemolysis and heme oxygenase-1 induction

It is not known why people are more susceptible to bacterial infections such as nontyphoid Salmonella during and after a malaria infection, but in mice, malarial hemolysis impairs resistance to nontyphoid Salmonella by impairing the neutrophil oxidative burst. This acquired neutrophil dysfunction is a consequence of induction of the cytoprotective, heme-degrading enzyme heme oxygenase-1 (HO-1) in neutrophil progenitors in bone marrow. In this study, we assessed whether neutrophil dysfunction occurs in humans with malaria and how this relates to hemolysis. We evaluated neutrophil function in 58 Gambian children with Plasmodium falciparum malaria [55 (95%) with uncomplicated disease] and examined associations with erythrocyte count, haptoglobin, hemopexin, plasma heme, expression of receptors for heme uptake, and HO-1 induction. Malaria caused the appearance of a dominant population of neutrophils with reduced oxidative burst activity, which gradually normalized over 8 wk of follow-up. The degree of neutrophil impairment correlated significantly with markers of hemolysis and HO-1 induction. HO-1 expression was increased in blood during acute malaria, but at a cellular level HO-1 expression was modulated by changes in surface expression of the haptoglobin receptor (CD163). These findings demonstrate that neutrophil dysfunction occurs in P. falciparum malaria and support the relevance of the mechanistic studies in mice. Furthermore, they suggest the presence of a regulatory pathway to limit HO-1 induction by hemolysis in the context of infection and indicate new targets for therapeutic intervention to abrogate the susceptibility to bacterial infection in the context of hemolysis in humans.

Assessment of HIV-1 patient recruitability in the Republic of Guinea-Bissau using African versus North American hematology and biochemistry reference intervals

Hematology and biochemistry reference intervals have been derived from healthy, HIV-negative populations to guide clinical trials worldwide. However, it is less clear how such values may be applied to clinical trials involving HIV-infected individuals. We show that contradictory interpretations about patient recruitability are reached when applying African versus North American reference intervals to an HIV-1 cohort in Guinea-Bissau. These observations underscore the need to question non-African guidelines in the context of HIV intervention clinical trials in Africa.

Haematological and biochemical reference values for healthy adults in the middle belt of Ghana

Background

Reference values are very important in clinical management of patients, screening participants for enrolment into clinical trials and for monitoring the onset of adverse events during these trials. The aim of this was to establish gender-specific haematological and biochemical reference values for healthy adults in the central part of Ghana.

Methods

A total of 691 adults between 18 and 59 years resident in the Kintampo North Municipality and South District in the central part of Ghana were randomly selected using the Kintampo Health and Demographic Surveillance System and enrolled in this cross-sectional survey. Out of these, 625 adults made up of 316 males and 309 females were assessed by a clinician to be healthy. Median values and nonparametric 95% reference values for 16 haematology and 22 biochemistry parameters were determined for this population based on the Clinical Laboratory and Standards Institute guidelines. Values established in this study were compared with the Caucasian values being used currently by our laboratory as reference values and also with data from other African and western countries.

Results

Reference values established include: haemoglobin 113–164 g/L for males and 88–144 g/L for females; total white blood cell count 3.4–9.2×10⁹/L; platelet count 88–352×10⁹/L for males and 89–403×10⁹/L for females; alanine aminotransferase 8–54 U/L for males and 6–51 U/L for females; creatinine 56–119 µmol/L for males and 53–106 µmol/L for females. Using the haematological reference values based on the package inserts would have screened out up to 53% of potential trial participants and up to 25% of the population using the biochemical parameters.

Conclusion

We have established a panel of locally relevant reference parameters for commonly used haematological and biochemical tests. This is important as it will help in the interpretation of laboratory results both for clinical management of patients and safety monitoring during a trial.

Developmental allometry and paediatric malaria

WHO estimates that 80% of mortality due to malaria occurs among infants and young children. Though it has long been established that malaria disproportionately affects children under age five, our understanding of the underlying biological mechanisms for this distribution remains incomplete. Many studies use age as an indicator of exposure, but age may affect malaria burden independently of previous exposure. Not only does the severity of malaria infection change with age, but the clinical manifestation of disease does as well: younger children are more likely to suffer severe anaemia, while older children are more likely to develop cerebral malaria. Intensity of transmission and acquired immunity are important determinants of this age variation, but age differences remain consistent over varying transmission levels. Thus, age differences in clinical presentation may involve inherent age-related factors as well as still-undiscovered facets of acquired immunity, perhaps including the rates at which relevant aspects of immunity are acquired. The concept of "allometry" - the relative growth of a part in relation to that of an entire organism or to a standard - has not previously been applied in the context of malaria infection. However, because malaria affects a number of organs and cells, including the liver, red blood cells, white blood cells, and spleen, which may intrinsically develop at rates partly independent of each other and of a child's overall size, developmental allometry may influence the course and consequences of malaria infection. Here, scattered items of evidence have been collected from a variety of disciplines, aiming to suggest possible research paths for investigating exposure-independent age differences affecting clinical outcomes of malaria infection.

Hematological reference values for healthy adults in togo

The hematological reference values are very important for diagnostic orientation and treatment decision. The aim of this study was to establish hematological reference values for healthy adults in Togo. A total of 2571 voluntary blood donors participated to this study. Only 1349 subjects negative for HIV, HBV, HCV, malaria, and without hemoglobin abnormalities in electrophoresis and hypochromia on blood smear, were definitively retained for the study. Median hemoglobin level was higher in males than females (15.1 g/dL versus 13.0 g/dL, p = 0.000). Median total WBC (4.2×10⁹/L) and absolute neutrophil counts (1.6×10⁹/L) were similar by gender. The median lymphocyte counts in males and females were, respectively, 2.1×10⁹/L and 2.2×10⁹/L (p = 0.11). The median platelet count was lower in males than females (236×10⁹/L versus 247×10⁹/L, p = 0.004). Our median values for RBC parameters differ from those of African countries probably because of our inclusion criteria which eliminate most cases with iron deficiency and/or thalassemia.

Tuberculosis case-contact research in endemic tropical settings: design, conduct, and relevance to other infectious diseases

The study of the contacts of patients with tuberculosis has a long history. Where tuberculosis is endemic, regular recruitment of tuberculosis cases and their household contacts can be done for research and strategic intervention. This recruitment provides a platform whereby host, pathogen, and environmental factors related to tuberculosis can be investigated and new interventions can be assessed. We describe the types of study possible within a tuberculosis case-contact study platform and its essential components, including recruitment and follow-up of the patients with tuberculosis, their household contacts and community controls, assessments and sampling, and data management and processing. Sample handling and storage, local engagement, ethical challenges, and the strengths and weaknesses of study design are all important issues in case-contact research. A case-contact study platform is a powerful research tool to answer fundamental questions in tuberculosis and has relevance to the study of other major infectious diseases.

Establishment of haematological and immunological reference values for healthy Tanzanian children in Kilimanjaro Region

OBJECTIVE

To determine the normal haematological and immunological reference intervals for healthy Tanzanian children.

METHODS

We analysed data from 655 HIV-seronegative, healthy children from 1 month to 18 years of age from the Kilimanjaro Region of Tanzania for this cross-sectional study. Median and 95% reference ranges were determined for haematological and immunological parameters and analysed by age cohorts, and by gender for adolescents.

RESULTS

Median haemoglobin (Hb) and haematocrit (Hct) for all age groups were higher than established East African reference intervals. Compared to U.S. intervals, reference ranges encompassed lower values for Hb, Hct, mean corpuscular volume, and platelets. Applying the U.S. National Institute of Health Division of AIDS (DAIDS) adverse event grading criteria commonly used in clinical trials to the reference range participants, 128 (21%) of 619 children would be classified as having an adverse event related to Hb level. CD4-positive T-lymphocyte absolute counts declined significantly with increasing age (P < 0.0001). For those aged under five years, CD4-positive T-lymphocyte percentages are lower than established developed country medians.

CONCLUSIONS

Country-specific reference ranges are needed for defining normal laboratory parameters among children in Africa. Knowledge of appropriate reference intervals is critical not only for providing optimal clinical care, but also for enrolling children in medical research. Knowledge of normal CD4-positive T-lymphocyte parameters in this population is especially important for guiding the practice of HIV medicine in Tanzania.