Reference intervals (RIs) are sets of percentiles that outline the range of laboratory test results belonging to healthy individuals. They are essential for the interpretation of laboratory test results. A wide variety of factors affect the validity of RIs. Among them are the statistical methods used to estimate RIs. However, little investigation has gone into the effect that different statistical methods have on the resulting RIs. This is particularly needed as the complexity of paediatric data makes it difficult to estimate RIs. These difficulties, however, can be addressed using appropriate statistical techniques, provided that there is an outline of scenarios under which these techniques are truly “appropriate”. The objective of this thesis is to provide a thorough investigation into the effect of different statistical methods on RIs. A systematic review was first conducted with a focus on paediatric RIs. The results of this review revealed that critical analysis steps are often overlooked due to complicated paediatric data. Even though a guideline addressing the establishment of RIs is available, there is great heterogeneity in the statistical methods chosen to estimate paediatric RIs. An extensive simulation involving the three most commonly used approaches to estimate RIs (the parametric, non-parametric, and robust methods) was also conducted to investigate and compare the performance of the different methods. The simulation results show that, when data follows a Gaussian distribution, or close to it, the parametric method provides the best estimates. The non-parametric method did not provide the best estimates of RIs (compared to the parametric method) unless data was highly skewed and/or large sample sizes were used. In addition, the bias and MSE associated with the parametric method when data follows a Gaussian distribution was mathematically derived, which may lead to the development of a bias corrected and more precise approach in the future. / Thesis / Master of Science (MSc)

Reference intervals are important estimates used to determine whether an individual is healthy or unhealthy. They are the most widely used decision making tool in medicine and heavily influence doctor’s decisions regarding patient care. Despite the abundance of reference interval research in the field of clinical chemistry, age-related reference intervals have yet to be well-established for elderly populations. Many physiological and biochemical changes have been documented to occur with age however limited attempts have been made to quantify these changes. As a result, it is typical in clinical practice to assess geriatric patient data using an adult reference interval. Such practices can result in over-medicalization, unnecessary medical procedures and/or missed diagnoses. This thesis aims to address this gap in literature by summarizing what geriatric reference intervals are available and by investigating how reference intervals are affected by the presence of morbidity, a common characteristic of the elderly. The first chapter of the thesis introduces the reader to reference intervals, summarizes the current guidelines used in their determination and provides a rationale for the use of age-related reference intervals in geriatrics. Chapter 2 presents a systematic review that summarizes all available reference intervals for populations ≥65 years of age and the methodology used in their determination. Despite extreme variability in methodology, evidence suggests that geriatric reference intervals are significantly different from those of adults for many analytes. Chapter 3 presents a study that evaluates the effect morbidity has on reference intervals. In this study data from the National Health and Nutrition Examination Survey (NHANES) was used to calculate age-specific reference intervals for creatinine, a marker of kidney function known to increase with age. Findings suggest that the presence of morbidity significantly increases the upper limit for creatinine in elderly populations. Finally, the concluding chapter summarizes the overall findings of the thesis, proposes areas for future research and reinforces the importance of the above findings. / Thesis / Master of Science (MSc) / Reference intervals are estimates used to determine whether an individual is healthy or unhealthy. In particular this thesis investigates reference intervals for blood test results. Currently no age-specific reference intervals for the elderly are used clinically, instead the normalcy of a blood test result for an elderly person is based on adult reference intervals. This process may lead to over-medicalization or missed diagnoses in geriatrics. Within this thesis is a systematic review of the literature that was performed to capture any available reference intervals that have been published for populations greater than 65 years of age. It was determined that a multitude of geriatric reference intervals are available in literature but they are not used clinically and have no standardized methodology for their determination. Despite this lack of standardization, studies proved that geriatric reference intervals are significantly different from those of adult populations. Given that morbidity or the presence of disease is common in older patients it was suspected this may be a reason for the difference in reference intervals. A separate study was then performed to determine whether the presence of disease affects reference interval calculations. Results from this study showed that the presence of disease affects reference intervals in older individuals more so than younger individuals.

Objectives: Phase 1) Establish echocardiographic reference intervals for measurements of the normal canine right heart. Phase 2) Describe the repeatability of normal right heart echocardiographic measurements. Phase 3) Describe the repeatability of right heart echocardiographic measurements which predict pulmonary artery pressure. Materials and Methods: Phase 1) 45 healthy adult dogs. Dogs underwent one echocardiographic examination by the same operator. Phase 2) 6 randomly selected dogs from the pool of Phase 1 dogs. Dogs underwent repeated echocardiograms by two operators. Phase 3) 4 client-owned dogs. Dogs underwent repeated echocardiographic examination by two operators. Results: Phase 1) The linear relationship between dimension and transformed body weight was highly variable. For linear dimensions, most of the scaling exponents were close to the theoretical value of 1/3. For area measurements, most of the scaling exponents were close to 2/3. Phase 2) Of the 168 within-day, between-day and between-operator coefficients of variation (CV) generated, 154 (91.7%) were below 15% and 135 (80.4%) were less than 10%. Phase 3) Of the 100 within-day, between-day and between-operator CVs generated, 72 (72%) were below 20% and 46 (46%) were below 10%. Conclusions: The right heart can be measured with relatively low repeatability. Measurement of the tricuspid regurgitation velocity should be the first priority when attempting to predict pulmonary artery pressure. If tricuspid regurgitation is not present, the use of transpulmonic acceleration time (AT) and the ratio of transpulmonic acceleration-to-ejection time (AT:ET) to indirectly assess pulmonary artery pressure is recommended. / Master of Science

In 1981, no representative study of the medical and social conditions among elderly persons in northern Scandinavia was performed. Nor was there such a study in a smaller Swedish town than Gothenburg. This study was initiated to fill that knowledge gap. The aim of the study was to evaluate gender and age differences in medical and social conditions among elderly people, including the reference intervals of clinical chemistry parameters and characteristic features of the 24-hour electrocardiogram (ECG) in healthy elderly. By way of longitudinal design with birth cohorts stratified by gender, it was assumed that the effects could be demonstrated. Also, the death risk of various social and medical variables was to be assessed. During the study period 1981 to 1990, the subjects were between 70 and 88 years of age. The proportion of persons living in private housing decreased from almost all at the age of 70 to slightly more than half at 88 years of age. The number of socially active persons decreased considerably during the period. The need of help increased from almost none to 60 % of the persons. The proportions of persons with normal sight and hearing decreased from two thirds to around one tenth The most frequent symptoms were general tiredness, pains, dyspnoea, constipation and dryness of the mouth. Cardiovascular diseases were the most frequent. Hypertensive disease became less, and congestive heart failure more frequent with age. The frequency of dementia increased steeply among the oldest persons; at 88 years of age, 40 % were demented. Drug consumption increased; the oldest persons in both age cohorts used 5 different drugs or more per person regularly. The consumption increase was mainly due to the increasing morbidity accompanying age. The most common drugs taken were cardiovascular preparations, psychoactive agents, drugs to alleviate gastrointestinal symptoms, and analgesics. Drug intake and symptom prevalence were generally higher in women, despite the fact that there was no gender difference in the number of diseases. The reference intervals of many blood components in healthy elderly were shown to be broader than those of younger persons. The intervals of P(lasma)-folate and P- potassium were on a lower and those of the erythrocyte sedimentation rate, P-creati- nine and, in women, S(erum)-cholesterol, were on a higher level than among younger persons. Several features of the 24-hour ECG, e.g. the number of episodes of supraventricular tachycardia as well as supraventricular and ventricular premature beats in healthy elderly were more frequent than among younger persons. Between 80 and 88 years of age, many functions crucial to the chances of living a rich and vital life were found deteriorating in the elderly persons. High age, male sex, dementia, congestive heart failure, and low values of S-creatinine were shown to be independent factors connected with an increased death risk. / <p>S. 1-112: sammanfattning, s. 115-177: 5 uppsatser</p> / digitalisering@umu.se

The presented thesis describes the historical evolution of growth and laboratory reference values and the methods for their creation – leading finally to a family of methods applied in the WHO Multicentre Growth Reference Study (MGRS). The following part describes these methods, their assumptions, and model diagnostics. The original article at the beginning of part III combines these methods with resampling to be able to use LMS -type methods on data containing different dependencies like follow-up measures and family relationships. This method has been applied in the estimation of reference values of several laboratory values in the context of the LIFE child study. Three papers are already published and are also presented. In part III. The next section concentrates on the accompanying R package childsds. A short summary and outlook conclude the work.:I Introduction 1 Introduction 1.1 Standardization and Reference Values 1.2 The Scope of this Thesis 2 Historical Aspects 2.1 Development of Basic Concepts 2.2 Growth References and Growth Charts 2.3 Laboratory Reference Values II Methods 3 Method Selection 3.1 Nomenclature 3.2 The Choice of Statistical Method 3.3 GAMLSS 3.4 LMS-type Methods 4 Model Diagnostics 4.1 Normalized Quantile Residuals 4.2 Diagnostic Plots 4.3 Numerical Statistics III Original Articles & R Pakackage 5 Original Article 6 Articles Using the Proposed Method 7 R Package childsds 7.1 The Example Data 7.2 The Fitting Functions 7.3 The Classes 7.4 The Back-transformation Function 7.5 Convenience Functions 7.6 Collection of Reference Values 8 Summary and Outlook 8.1 Summary 8.2 SDS Values and Quality Control 8.3 The R Package / Die vorliegende Arbeit soll die Entwicklung und Bedeutung von Referenzwerten im pädiatrischen Kontext beschreiben. Der zugehörige Artikel beschreibt die Kombination der von der WHO empfohlene Methode und Resampling, um die Herleitung von Referenzwerten auch im Fall von Messwiederholungen und anderen Abhängigkeiten zu ermöglichen. Drei weitere Artikel, in denen die Methode angewendet wurde und eine kurze Vorstellung des zugehörigen, begleitend entwickelten R Pakets (statistische Software) bilden Teil III der Arbeit.:I Introduction 1 Introduction 1.1 Standardization and Reference Values 1.2 The Scope of this Thesis 2 Historical Aspects 2.1 Development of Basic Concepts 2.2 Growth References and Growth Charts 2.3 Laboratory Reference Values II Methods 3 Method Selection 3.1 Nomenclature 3.2 The Choice of Statistical Method 3.3 GAMLSS 3.4 LMS-type Methods 4 Model Diagnostics 4.1 Normalized Quantile Residuals 4.2 Diagnostic Plots 4.3 Numerical Statistics III Original Articles & R Pakackage 5 Original Article 6 Articles Using the Proposed Method 7 R Package childsds 7.1 The Example Data 7.2 The Fitting Functions 7.3 The Classes 7.4 The Back-transformation Function 7.5 Convenience Functions 7.6 Collection of Reference Values 8 Summary and Outlook 8.1 Summary 8.2 SDS Values and Quality Control 8.3 The R Package

(1) Background: Highly sensitive cardiac troponin T (hs-cTnT) plays an essential role in the diagnosis of myocardial injury. The upper reference limit of the respective assay is generally applied, irrespective of age, renal function, or sex. We aimed to identify age-adjusted and sex-adjusted upper reference limits in relation to renal function in a large population-based cohort without cardiac diseases. (2) Methods: We included 5428 subjects of the population-based LIFE-Adult cohort, free of diagnosed cardiac diseases. Sex-adjusted and age-adjusted 99th percentiles for hs-cTnT in subjects with preserved renal function were obtained. (3) Results: The hs-cTnT values were higher in men of all age groups. In both sexes, an increasing age positively correlated with higher hs-cTnT values. Hs-cTnT weakly correlated with serum creatinine. The three-dimensional analysis of age, creatinine, and hs-cTnT showed no relevant additional effect of creatinine on hs-cTnT. In men aged above 60 and women above 70, the calculated 99th percentiles clearly exceeded the commonly applied thresholds. (4) Conclusion: Age and sex have a major impact on the serum concentration of hs-cTnT, while renal function does not. We propose to consider age-adjusted and sex-adjusted reference values.

No description available.

Aquacultured products assist the human demands for seafood so that foodfish supplies can remain sustainable and consistent. Although the fish-farming industry has seen dramatic growth and intensification in recent years, the latter has led to an increase in bacterial diseases and fish health management problems, resulting in major economic losses around the world. In addition to the lack of understanding of fish physiology, these complications are exacerbated by the inappropriate and controversial use of antibiotics. This work addressed these issues in striped catfish (Pangasius hypophthalmus) and Nile tilapia (Oreochromis niloticus), two economically important foodfish, by investigating alternative, more cost-effective options to promote fish health. The first two studies established reference intervals for immunology, hematology and plasma chemistry analytes in striped catfish in a recirculating aquaculture system (RAS). In a third study, the immunomodulatory effects after directly feeding probiotic strains of Bacillus subtilis NZ86 and O14VRQ in Nile tilapia were ascertained. This last study revealed that supplementation with both of the probiotic strains for 51 days stimulated several local and systemic innate immune responses of tilapia. When these transient probiotic bacteria were present in the gut, a pro-inflammatory environment was developed as evidenced by the localized higher expression of the cytokines tumor necrosis factor (TNF) – α and interleukin (IL) – 1β. Significant increases (p < 0.05) were noted differentially by both probiotic strains throughout the trial in plasma lysozyme content, alternative complement activity, and in the peripheral blood leukocyte profiles. Additionally, there were trends for increased levels of phagocytosis and respiratory burst in leukocytes of the anterior kidney and spleen at the end of the trial, suggesting the potential use of these probiotic strains for improved immune-competence. These findings help to understand and clarify the potential mechanism of action associated with the increased disease resistance recorded in preliminary studies with the same probiotic strains. Implementation of the tools established and validated in this work could be useful in evaluating fish welfare situations involving striped catfish grown in RAS conditions, and also show promise for a healthier foodfish supply where antibiotic applications practices could be minimized. / Ph. D.

A determinação de Intervalos de Referência (IR) é uma árdua tarefa para os laboratórios clínicos, porém indispensável e de fundamental importância para a tomada de decisão médica. Para parâmetros como os lípides séricos, os IR tem sido estabelecidos consensos nacionais ou internacionais definindo limites de decisão (CLSI, 2008). O objetivo deste estudo foi determinar os IR para colesterol total, HDL-colesterol, colesterol não-HDL, LDL- colesterol e triglicérides séricos em crianças e adolescentes saudáveis do município de Cuiabá, capital do estado de Mato Grosso. Trata-se de um estudo transversal, descritivo, realizado em 1.866 crianças e adolescentes saudáveis de creches e escolas municipais desta capital, obtidas por amostragem aleatória. Foi aplicado um questionário avaliando antecedentes do indivíduo e de seus familiares além de dados demográficos e antropométricos. Foram definidos como critérios de inclusão do estudo, crianças e adolescentes nas faixas etárias de 1 a 12 anos 11 meses e 29 dias, sem nenhuma doença de base diagnosticada ou queixas clínicas no momento da coleta. Além disto, os participantes não deveriam fazer uso regular de medicamento. As amostras foram coletadas em jejum. As amostras foram processadas no equipamento cobas® 6000 (analyser series - Roche Diagnostics), em laboratório da rede DASA na cidade de Cuiabá. Em relação à metodologia estatística, foi analisada a homogeneidade das variâncias através do teste de Bartlett para cada analito por idade e, posteriormente, testados pelo teste ANOVA ou Kruskal-Wallis para verificar a existência de diferença entre as faixas etárias. O teste \"post hoc\" de Bonferroni foi aplicado quando se constatou a diferença para reagrupar as faixas etárias similares, constituindo assim novos grupos etários. Aplicou-se então, o teste de Bartlett e, conforme seu resultado, realizou-se ANOVA ou Kruskal-Wallis para verificar se os agrupamentos nas faixas se mantinham. Em seguida, procedeu-se a exclusão de valores extremos (outiliers) tomados como sendo aqueles valores acima ou abaixo da média ± 3 desvios-padrão. Depois de excluídos os outiliers, obteve-se o IR como sendo a média ± 2 desvios-padrão dos valores remanescentes. Adicionalmente, foi calculada a distribuição em percentis, sendo adotado o critério do NHLBI 2012 como proposta de limite de decisão para a população estudada. Em todos os testes, o nível de significância adotado foi de 5%. As análises estatísticas foram realizadas pelos programas MINITAB (versão 15) e SPSS (versão 16). Este projeto foi aprovado pelas Comitês de Ética em Pesquisa das instituições envolvidas e das Secretarias Municipais de Educação e Saúde de Cuiabá. Os valores encontrados para o colesterol total, nos percentis 75 e 95 foram: 1 a 2 anos de 160 mg/dL e 189 mg/dL; 3 a 8 anos de 170 mg/dL e 199 mg/dL; 9 a 12 anos de 176 mg/dL e 205 mg/dL, respectivamente. Para o colesterol não-HDL, na única faixa etária de 1 a 12 anos, os valores nestes percentis foram de 122 mg/dL e 150 mg/dL, respectivamente. Para o LDL-colesterol, os valores correspondentes aos percentis acima, na faixa etária de 1 a 8 anos e de 9 a 12 anos, foram de 104 mg/dL e 132 mg/dL; 106 mg/dL e 139 mg/dL, respectivamente. Para os triglicérides, os valores correspondentes aos referidos percentis foram: 1 ano de 127 mg/dL e 189 mg/dL; 2 a 5 anos de 98 a 139 mg/dL; 6 a 12 anos de 92 mg/dL e 139 mg/dL. Para as faixas etárias propostas para o HDL-colesterol os valores correspondentes ao percentil 10 foram: 1 ano de 24 mg/dL; 2 anos de 28 mg/dL; 3 anos de 32 mg/dL e de 4 a 12 anos foi de 36 mg/dL. Os valores dos parâmetros aqui avaliados, definidos em diferentes faixas etárias em crianças e adolescentes brasileiros da cidade de Cuiabá, podem representar limites de decisão para a população pediátrica brasileira contribuindo para aprimorar o diagnóstico neste grupo específico em nosso país / Establishment of Reference Intervals (RI) is an arduous task for clinical laboratories however vital and fundamental importance to medical decision making. For some parameters, such as serum lipids, RI have been established by national and international consensus defining decision limits (CLSI 2008). The aim of this study was to determine pediatric RI of total cholesterol, HDL-cholesterol, cholesterol non- HDL, LDL-cholesterol and triglycerides in healthy children and adolescents in Cuiabá, capital of Mato Grosso. This is a descriptive study, conducted in 1,866 healthy children and adolescents from kindergartens and schools of the capital city, obtained by random sampling. A questionnaire assessing the individual background and their relatives besides demographic and anthropometric data had beeb also carried out. Were defined as inclusion criteria of the study, children and adolescents in the group 1-12 years 11 months and 29 days without any underlying disease or diagnosed clinical complaints at the time of collection. In addition, participants should not take any regular medication. The samples were collected during fasting period and were determined using cobas® 6000 (analyser series - Roche Diagnostics). Regarding statistic methodology, we did analyse the homogeneity of variances by Bartlett´s test for each parameter by age and subsequently by ANOVA or Kruskal-Wallis test to check the differences between age groups. The test \"pos hoc\" Bonferroni was applied when it was found the difference to regroup similar age groups, thus constituting a new age bracket. After this procedure the Bartllet test was applied, as it result, we did conduct ANOVA or Kruskal-Wallis to check if the groups remained. Then proceeded to the exclusion of extreme values (outliers) taken as those values above or below the mean ± 3 standard deviations. After excluding outliers, obtained the RI as the mean ± 2 standard deviations of the remaining values. Additionally, we calculated the percentile distribution, and adopted the criteria of NHLBI 2012 as proposed decision limit for the population studied. In all tests, the significance level was 5%. Statistical analyzes were performed by Minitab software (version 15) and SPSS (version 16). The project was approved by the Research Ethics Committees of the institutions involved and Municipal Departments of Education and Health of Cuiabá city The values obtained for total cholesterol, 75 and 95 percentiles, were: 1 to 2 years, 160 mg/dL and 189 mg/dL; 3 to 8 years, 170 mg/dL and 199 mg/dL; 9 to 12 years, 176 mg/dL and 205 mg/dL, respectively. For the non-HDL cholesterol, the only age group 1 to 12 years, this percentiles values were 122 mg/dL and 150 mg/dL, respectively. For the LDLcholesterol, the values corresponding to the percentiles above, aged 1 to 8 years and 9 to 12 years, were 104 mg/dL and 132 mg/dL; 106 mg/dL and 139 mg/dL, respectively. For the triglycerides, the values corresponding to these percentiles were: 1 year, 127 mg/dL and 189 mg/dL; 2 to 5 years, 98 to 139 mg/dL; 6 to 12 years, 92 mg/dL and 139 mg/dL. For ages proposed for HDL-cholesterol the corresponding values to 10th percentile were: 1 year, 24 mg/dL; 2 years, 28 mg/dL; 3 years, 32 mg/dL and 4 to 12 years were 36 mg/dL. The values of the parameters evaluated here, defined in different age groups in Brazilian children and adolescents in the city of Cuiabá, can represent decision limits for the Brazilian pediatric population contributing to improve the diagnosis in this particular group in our country

O sangue é uma suspensão de células contidas num líquido complexo chamado plasma. O termo sangue total refere-se a amostras de sangue com a totalidade de seus constituintes, parte sólida e líquida. Sendo os elementos químicos responsáveis por funções essenciais, como regulação osmótica, frequência cardíaca e contratibilidade, coagulação sanguínea e excitabilidade neuromuscular. A determinação de elementos químicos em fluidos corporais como sangue, soro, plasma, tecido e urina é usada como monitor de parte ou de todo o organismo. Nesse trabalho, utilizou-se a técnica de fluorescência de raios X (EDXRF) para análise de amostras de sangue total humano e animal, hamsters da espécie dourada (Mesocricetus auratus) e cavalos da raça crioula (Equus caballus). Nas amostras de sangue humano, foram determinados intervalos de referência de Na (1788 - 1826 &mu;g g-1), Mg (63 - 75 &mu;g g-1), P (602 - 676 &mu;g g-1), S (1519 - 1718 &mu;g g-1), Cl (2743 - 2867 &mu;g g-1), K (1508 - 1630 &mu;g g-1), Ca (214 - 228 &mu;g g-1), Cu (4 - 6 &mu;g g-1) e Zn (1 - 3 &mu;g g-1). Foram determinados intervalos de referência de Na (1714 - 1819 &mu;g g-1), Mg (51 - 79 &mu;g g-1), P (970 - 1080 &mu;g g-1), S (1231 - 1739 &mu;g g-1), Cl (2775 - 2865 &mu;g g-1), K (1968 - 2248 &mu;g g-1), Ca (209 - 257 &mu;g g-1), Cu (4 - 6 &mu;g g-1) e Zn (3 - 5 &mu;g g-1) para amostras de sangue de hamster dourado. As amostras de sangue de cavalo da raça crioula apresentaram os intervalos de: Na (1955 - 2013 &mu;g g-1), Mg (51 - 75 &mu;g g-1), P (443 - 476 &mu;g g-1), S (1038 - 1140 &mu;g g-1), Cl (2388 - 2574 &mu;g g-1), K (1678 - 1753 &mu;g g-1), Ca (202 - 213 &mu;g g-1), Cu (4,1 - 4,5 &mu;g g-1) e Zn (2,0 - 2,2 &mu;g g-1). Estudo comparativo dos resultados entre as técnicas de análise por ativação neutrônica (NAA) e EDXRF indica a igualdade de desempenho das técnicas analíticas na análise de matrizes biológicas. Os resultados contribuem no estabelecimento de intervalos de referência para a população brasileira saudável e para as referidas espécies de animais. / Blood is a suspension of cells contained in a complex liquid called plasma. The term whole blood refers to samples with both solid and liquid parts. Inorganic elements are responsible for essential functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma, tissue and urine is used as a monitor for a part or the whole organism. In this work, the X-Ray fluorescence technique (EDXRF) was used for the determination of inorganic elements in whole blood samples from humans and animals (golden hamsters, Mesocricetus auratus and crioula breed horses, Equus caballus). The reference intervals of Na (1788 - 1826 &mu;g g-1), Mg (63 - 75 &mu;g g-1), P (602 - 676 &mu;g g-1), S (1519 - 1718 &mu;g g-1), Cl (2743 - 2867 &mu;g g-1), K (1508 - 1630 &mu;g g-1), Ca (214 - 228 &mu;g g-1), Cu (4 -6 &mu;g g-1) e Zn (1 - 3 &mu;g g-1) were determined for human blood. The reference intervals, for golden hamster blood were found to be: Na (1714 - 1819 &mu;g g-1), Mg (51 - 79 &mu;g g-1), P (970 - 1080 &mu;g g-1), S (1231 - 1739 &mu;g g-1), Cl (2775 - 2865 &mu;g g-1), K (1968 - 2248 &mu;g g-1), Ca (209 - 257 &mu;g g-1), Cu (4 - 6 &mu;g g-1) e Zn (3 -5 &mu;g g-1). The reference intervals, for crioula breed horse blood, showed to be: Na (1955 - 2013 &mu;g g-1), Mg (51 - 75 &mu;g g-1), P (443 - 476 &mu;g g-1), S (1038 - 1140 &mu;g g-1), Cl (2388 - 2574 &mu;g g-1), K (1678 - 1753 &mu;g g-1), Ca (202 - 213 &mu;g g-1), Cu (4,1 - 4,5 &mu;g g-1) e Zn (2,0 - 2,2 &mu;g g-1). Comparative study between NAA and EDXRF, both techniques showed the same performance for the analyses of biological matrices. The results contribute for the establishment of reference intervals for the Brazilian healthy population and the referred animal species.