Performance and reference intervals of thrombin generation test: results from the Brazilian longitudinal study of adult health (ELSA-Brasil). A cross-sectional study

ABSTRACT BACKGROUND: The thrombin generation test (TGT) has shown promise for investigation of hemorrhagic and thrombotic diseases. However, despite its potential, it still needs standardization. Moreover, few studies have established reference values for TGT parameters. In Brazil, these values have not yet been established. OBJECTIVE: To determine TGT performance and reference intervals for TGT parameters in healthy individuals. DESIGN AND SETTING: Cross-sectional study conducted among participants in the Brazilian Longitudinal Study of Adult Health (Estudo Longitudinal de Saúde do Adulto, ELSA-Brasil). METHODS: The reference sample consisted of 620 healthy individuals. The calibrated automated thrombogram (CAT) method, under low and high tissue factor (TF) conditions, was used to assess thrombin generation. Test performance was analyzed using intra and interassay coefficients of variation (CV) and reference intervals were calculated using the nonparametric method proposed by the International Federation of Clinical Chemistry and the Clinical and Laboratory Standards Institute. RESULTS: The intraassay CV ranged from 1.4% to 2.2% and the interassay CV, 6.8% to 14.7%. The reference intervals for TGT parameters under low and high TF conditions were, respectively: lagtime: 3.0-10.3 and 1.4-3.7 min; endogenous thrombin potential (ETP): 1134.6-2517.9 and 1413.6-2658.0 nM.min; normalized ETP: 0.6-1.3 and 0.7-1.4; peak: 103.2-397.7 and 256.4-479.0 nM; normalized peak: 0.3-1.3 and 0.7-1.2; and time-to-peak: 5.6-16.0 and 3.4-6.7 min. These parameters were categorized relative to sex. Conclusion: TGT performance was adequate and the proposed reference intervals were similar to those of other studies. Our findings may be useful for consolidating the TGT, through contributing to its standardization and validation.

Hematological Profiles of Eligible Blood Donors at Kenyatta National Hospital, Kenya

Aim:To determine hematological profile of eligible blood donors at Kenyatta National Hospital (KNH), Kenya.Study Design:Adopted a cross-sectional study.Place and Duration of Study:Kenyatta National Hospital, between March 2021 and August 2021.Methodology:This study recruited 202 eligible blood donors comprising of 173 males and 29 females aged 18-57 years. Blood samples (4ml) were drawn from donated units into ethylene diamine tetraacetic acid (EDTA) tube. Hematological parameters were estimated using a complete blood count (CBC) analyzer (Humacount 5D®). A total of eighteen hematological parameters were analyzed. These parametersincluded; red blood cell (RBC) count, hemoglobin concentration, RBC indices, white blood cell (WBC) count, absolute and differential WBC and platelet (PLT) count. Results were presented in medians and 95% interquartile ranges and compared using Mann–Whitney U test.Results:The median counts for all hematological parameters were within the accepted reference ranges for the adult urban population in Kenya. The median and interquartile range for total red cell count was 4.9×106/μL [0.74], hemoglobin level was 14.3g/dL[1.8], hematocrit was 44.9% [5.1], white blood count was 4.9×103/μL [1.4] and platelet was 234×103/L [64]. Among the red cell parameters analyzed, male donors had a significantly higher RBC count (P<0.001), hematocrit (P=0.001) and hemoglobin (P<0.001) than female donors. Among white blood cell parameters analyzed, only lymphocytes (P=0.011) were significantly higher in female donors than male donors. Platelet count (P<0.001) was also significantly higher in females than male donors.Conclusion:This study showed eligible donors at KNH had significant differences in red cell count, hematocrit, hemoglobin, lymphocytes and platelets between male and female donors. Additionally, it highlighted that some blood donors had hematological parameters belowand above the recommended reference ranges. These findings support the need to review the current donor recruitment criteria recommending the inclusion of complete blood count in screening.

Caracterização dos distúrbios da regulação ácido-base: uma abordagem didática e intuitiva / Characterization of acid-base regulation disorders: a didactic and intuitive approach

Em humanos, o pH sanguíneo é mantido em uma faixa estreita, entre 7,35 e 7,45. Diferentes mecanismos bioquímicos, de forma harmônica, atuam para a manutenção do pH fisiológico. Múltiplos processos patológicos podem promover alterações no pH e nos gases sanguíneos, caracterizando acidose (pH <7,35) ou alcalose (pH >7,45). A ruptura da homeostasia do pH é identificada pela medição do pH, pressão parcial de dióxido de carbono (pCO2), concentração do bicarbonato (HCO3-) e, adicionalmente, com a pressão de oxigênio (pO2) em sangue arterial, processo descrito como gasometria arterial. Este artigo revisa os principais elementos associados a compreensão das alterações e tem como objetivo central apresentar uma abordagem didática e intuitiva para a caracterização destes distúrbios; e também comenta sobre ferramentais digitais destinadas a interpretações das alterações da gasometria arterial que também são abordados, como programas para computadores em ambiente web e aplicativos para telefonia móvel.

In humans, blood pH is kept in a narrow range, between 7.35 to 7.45. Different biochemical mechanisms, in a harmonic way, act to maintain the physiological pH. Multiple pathological processes can promote changes in pH and blood gases, characterizing acidosis (pH <7.35) or alkalosis (pH> 7.45). The rupture of pH homeostasis is identified by measuring pH, partial pressure of carbon dioxide (pCO2), bicarbonate concentration (HCO3 - and, in addition, with the pressure of oxygen (pO2) in arterial blood, a process described as gasometry arterial. This article reviews the main elements associated with the understanding of acid-base changes and aims to present a didactic and intuitive approach to the characterization of these disorders; and also comments on digital tools for the interpretation of alterations in arterial blood gases are also covered, such as programs for computers in a web environment and applications for mobile phone.

Thyroid function of twin-pregnant women in early pregnancy / 中华医学杂志(英文版)

Background@#Serum human chorionic gonadotrophin (hCG) is higher in twin than that in singleton pregnancies. As hCG stimulates the thyroid to produce more free thyroxine (FT4), which may lead to decreased thyroid-stimulating hormone (TSH) levels, the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester. This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies.@*Methods@#Data of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018; 160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges. We screened 480 (3:1 paired) women with singleton pregnancies from the same database as controls. The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies.@*Results@#First-trimester reference ranges (4–12 gestational weeks) for twin pregnancies were: TSH 0.69 (0.01–3.35) mIU/L and FT4 16.38 (12.45–23.34) pmol/L. Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks (0.62 vs. 0.96 mIU/L, Z = -1.964, P = 0.049); FT4 was not significantly different between the two groups. Compared to singleton pregnancies, median TSH was significantly lower (0.69 vs. 1.27 mIU/L, Z = -6.538, P = 0.000), and FT4 was significantly higher (16.38 vs. 14.85 pmol/L, Z = -7.399, P = 0.000) in twin pregnancies in the first trimester.@*Conclusions@#Specific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction. Moreover, establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered.

Reference Ranges for Ultrasonographic Measurements of the Uterine Cervix in Low-Risk Pregnant Women / Valores de referência das medidas ultrassonográficas do colo uterino em gestantes de baixo risco

Abstract Objective To define transvaginal ultrasound reference ranges for uterine cervix measurements according to gestational age (GA) in low-risk pregnancies. Methods Cohort of low-risk pregnantwomen undergoing transvaginal ultrasound exams every 4 weeks, comprisingmeasurements of the cervical length and volume, the transverse and anteroposterior diameters of the cervix, and distance fromthe entrance of the uterine artery into the cervix until the internal os. The inter- and intraobserver variabilities were assessed with the linear correlation coefficient and the Student t-test. Within each period of GA, 2.5, 10, 50, 90 and 97.5 percentiles were estimated, and the variation by GA was assessed with analysis of variance for dependent samples. Mean values and Student t-test were used to compare the values stratified by control variables. Results After confirming the high reproducibility of the method, 172 women followed in this cohort presented a reduction in cervical length, with an increase in volume and in the anteroposterior and transverse diameters during pregnancy. Smaller cervical lengths were associated with younger age, lower parity, and absence of previous cesarean section (C-section). Conclusion In the studied population, we observed cervical length shortening throughout pregnancy, suggesting a physiological reduction mainly in the vaginal portion of the cervix. In order to better predict pretermbirth, cervical insufficiency and premature rupture of membranes, reference curves and specific cut-off values need to be validated.

Resumo Objetivo Elaborar curvas de referências de medidas ultrassonográficas de colo uterino por idade gestacional (IG) em gestações de baixo risco. Métodos Coorte de gestantes de baixo risco, submetidas a ultrassom transvaginal repetido a cada 4 semanas, com medida do comprimento, dos diâmetros anteroposterior e transverso, da distância entre a entrada da artéria uterina no colo e o orifício interno, e do volume do colo. Foi avaliada a variabilidade inter e intraobservador entre as medidas com o coeficiente de correlação linear e teste t de Student. Para cada faixa de IG, estimaram-se os percentis 2,5, 10, 50, 90 e 97,5 dos valores das medidas, com a variação por IG avaliada por análise de variância para amostras dependentes. As comparações dos valores por variáveis de controle foram feitas por meio dos cálculos de médias e teste t de Student. Resultados Assegurada a alta reprodutibilidade do método, as 172 mulheres acompanhadas na coorte apresentaram redução das medidas de comprimento de colo com o decorrer da gestação, com aumento de volume e dos diâmetros anteroposterior e transverso. O menor comprimento cervical foi associado à menor idade materna, menor paridade, e ausência de cesárea prévia. Conclusão Na população estudada foi observada redução no comprimento cervical com o decorrer da gestação, sugerindo encurtamento fisiológico principalmente à custa da porção vaginal do colo. Há a necessidade de validar tais curvas de referência e pontos de corte específicos para uma melhor predição de risco de parto pré-termo, insuficiência cervical, e amniorrexe prematura.

Reference range of left ventricular strain measured by three-dimensional speckle-tracking imaging:Meta analysis / 中国介入影像与治疗学

Objective To obtain the normal reference ranges of global longitudinal strain (GLS),global circumferential strain (GCS),global area strain (GAS) and global radial strain (GRS) of left ventricular in normal adults by three-dimensional speckle tracking imaging (3D-STI) using Meta analysis.Methods Eligible trials which detected global strain of left ventricular in normal subject through 3D-STI were searched in Embase,Pubmed,Cochrane Library database.According to the heterogeneity,parameters of contained studies were analyzed the weighted mean difference (WMD) and 95％ confidence interval (CI).The statistical software was STATA 12.0.Results Totally 1 552 healthy adults from 27 articles were included.Based on the Meta-analysis,theWMDand 95％CIofGLSwere 17.80 and (16.27,19.33),of GCS were 24.73 and (22.50,26.95),of GRS were 47.86 and (39.52,56.19),of GAS were 36.17 and (34.08,38.26).Conclusion The Meta analysis defines reference range of strains obtained by 3D-STI in healthy adults.Using these parameters of 3D globe strains,a guidance of reference for patienfs management and therapy selection may be provided.

Establishment of reference range for thromboelastography in pregnancy / 中国输血杂志

Objective To establish a reference range for the normal value of thromboelastography (TEG) in pregnant females.Methods According to the results of pregnancy and physical examination,166 pregnant females and 64 healthy females without pregnancy were selected as the pregnant group and the non-pregnant control group,respectively.The TEG value and the traditional coagulation index were measured.The TEG parameters of the two groups were compared and analyzed,establishing a reference range for the parameters.We further analyzed the effect of full-term pregnancy on TEG results and the correlation between traditional coagulation index and TEG test results.Results The traditional coagulation index and TEG test results of the pregnant females andthe non-pregnant females were significantly different.According to the results,a new TEG reference range was established:R 3.9-7.5 min,K 1.0-2.4 min,α 57.6°-74.9°,MA 55.7-75.7 mm,LY30 0-0.56％,CI(-0.97)-3.6.Full-term pregnancy had no significant effect on TEG results.In addition to LY30,other parameters of TEG had some correlation with the traditional coagulation index.Conclusions The general TEG reference range does not apply to pregnant females and established TEG normal reference range for pregnant females can be applied for clinical use.

Establishment of variables-specific reference ranges of von Willebrand factor antigen and activity / 中国输血杂志

Objective To analyze the screening results of yon Willebrand factor among patients before blood transfusion in Ruijin Hospital and discuss von Willebrand factor in ABO blood group and the relationship between age and gender,refine the classification of vWF antigen and activity by reference factors.Methods The von Willebrand factor among 247 cases of patients before blood transfusion in Ruijin Hospital with no clinical manifestations of abnormal blood clots and routine coagulation as laboratory tests for normal surgical patients.The vWF:Ag and vWF:Act were measured by immune turbidimetric method and ABO blood group was identified by blood type serology.Furthermore,the differences between A,B,O,AB different blood groups,sex and high (≥40 years) and low age group (＜40 years) were compared by statistical methods.Results The levels of vWF:Ag in different blood groups were as follows:A blood type:98.5-142.00,B blood type:97.90-160.30,O blood type:82.13-125.45,A B blood type:103.00-135.80.The levels of vWF:Act in different blood groups were as follows:A blood type:76-130.14,B blood type:78.06-144.3,O blood type:60.89-116.11,AB blood type:88.99-124.09.O blood type vWF:Ag and vWF:Act were lower significantly (P＜0.05) than non-O blood type,the difference was.Besides,young vWF:Ag and vWF:Act were lower significantly than in the elderly.There was no significant difference in vWF:Ag and vWF:Act levels between male and female groups.At last,the reference range of four groups of vWF activity (antigen) was obtained.Conclusion Plasma vWF antigen and activity levels were significantly affected by ABO blood type and age,and the refined reference range established for these influencing factors was beneficial for more detailed diagnosis of VWD and predicting vWF levels associated with bleeding and thrombosis risk.

Concentración de insulina e índices de insulinosensibilidad en niños y adolescentes sanos / Insulin level and insulin sensitivity indices among healthy children and adolescents

Introducción. Existe escasa información acerca de los valores de referencia de la insulina y de los índices de insulinosensibilidad en pediatría. Objetivo. Describir la variación de insulina e índices subrogantes de insulinosensibilidad en la etapa pediátrica. Población y métodos. Variación de la concentración de insulina en ayuno y de los índices subrogantes, como el modelo de evaluación homeostática de resistencia a la insulina (homeostasis model assessment of insulin resistance; HOMA-IR, por sus siglas en inglés), en niños sanos con la edad, el índice de masa corporal, estadio puberal (EP), la concentración de IGF-I, colesterol total y triglicéridos. Resultados. Se incluyeron 226 niños sanos (1-18 años). La insulina aumentó con la edad, el índice de masa corporal, el EP, los niveles de IGF-I y triglicéridos (r²= 0,38; p 7,5 años presentaron mayores valores de insulina [mediana (Pc3 y Pc97) pUI/ mL: 5,0 (1,7-9,6)] que los prepuberales < 7,5 años [2,9 pUI/mL (1,3-10,9); p < 0,01]. En la pubertad (del EP II al EP V), la insulina fue mayor en las niñas que en los varones [(7,4 (1,8-16,9) versus 5,8 (1,8-12,9); p 7,5 años: 1,1 (0,3-2,0) versus niños < 7,5 años: 0,6 (0,3-1,4; p < 0,01). Los grupos puberales presentaron niveles más elevados de insulina y de HOMA-IR respecto de los niños prepuberales (p 2,0 y > 2,6 en prepúberes y púberes, respectivamente, podrían alertar a los pediatras sobre un posible estado de insulinorresistencia.

Introduction. Information on insulin reference values and insulin sensitivity indices in the field of pediatrics is scarce. Objective. To describe insulin range and insulin sensitivity surrogate indices during childhood. Population and methods. Fasting insulin level range and surrogate indices, such as the homeostasis model assessment of insulin resistance (HOMA-IR), among healthy children and adolescents by age, body mass index, pubertal stage (PS), insulin-like growth factor-1 (IGF-1), total cholesterol, and triglycerides. Results. Two hundred and twenty-six healthy children and adolescents (1-18 years old) were included. Insulin increased with age, body mass index, pubertal stage, IGF-1 and triglyceride levels (r²= 0.38, p 7.5 years old had higher insulin levels [median (P3 and P97) pIU/mL: 5.0 (1.7-9.6)] than prepubertal children < 7.5 years old [2.9 pIU/ mL (1.3-10.9), p < 0.01]. During puberty (from PS II to PS V), insulin was higher in girls than in boys [7.4 (1.8-16.9) versus 5.8 (1.8-12.9), p 7.5 years old: 1.1 (0.32.0) versus children < 7.5 years old: 0.6 (0.3-1.4, p < 0.01). The insulin level and HOMA-IR results were higher in pubertal children compared to the prepubertal group (p 2.0 and > 2.6 in prepubertal and pubertal children, respectively, may be considered a warning sign for pediatricians to further investigate insulin resistance.

Vitamin B12 Levels of Subjects Aged 0-24 Year(s) in Konya, Turkey.

Research reports indicate that vitamin B12 levels show racial differences, which suggests that using the reference ranges of varied populations may lead to inaccurate results. This study aimed to determine normal serum levels of vitamin B12 among children and young people in the Konya region of Turkey. It evaluated 1,109 samples; 54 were from cord-blood and 1,055 were from healthy subjects aged 0-24 year(s), who were admitted to primary healthcare centres. The normal reference levels obtained for vitamin B12 at 2.5-97.5 percentile (P2.5-P97.5) range were 127-606 pg/mL for girls, 127-576 pg/mL for boys, and 127-590 pg/mL for the entire study group. The reported reference values for vitamin B12 in other studies were higher than the current results. Vitamin B12 levels vary from country to country; comparisons between countries may not be valid, and normal levels for each population should be obtained.

Perfil bioquímico y valores de referencia en sangre del cordón umbilical / Biochemical profile and reference values in umbilical cord blood / Perfil bioquímico e os valores de referência no sangue do cordão umbilical

Cumpliendo con el propósito fundamental de la medicina de laboratorio que es aportar al especialista información que le sea de utilidad en el proceso de decisión médica, el objetivo del trabajo fue establecer el perfil bioquímico de recién nacidos sanos de Villa Clara a través de la cuantificación de indicadores en sangre del cordón umbilical y estimar, preliminarmente, en dichos analitos sus valores de referencia para esta población. Se utilizó como muestra el suero obtenido de la sangre del cordón umbilical de 80 recién nacidos sanos (40 de sexo femenino y 40 de sexo masculino) que cumplieron los criterios de inclusión establecidos para este estudio. Se cuantificaron parámetros de química clínica (urea, creatinina, alaninamino transferasa, aspartatoamino transferasa, bilirrubina total, fosfatasa alcalina, gamma-glutamiltransferasa, colesterol, triglicéridos y VLDL), inmunológicos (inmunoglobulinas IgM, IgG e IgA, y las proteínas C3 y C4 del sistema del complemento) y de minerales (hierro, cobre, cinc sodio, potasio, magnesio y calcio). Finalmente se establecieron los valores de referencia para cada parámetro, tomando el intervalo interpercentil correspondiente al intervalo central (95%) delimitado por los percentiles 2,5 y 97,5. No se encontraron diferencias estadísticamente significativas en dependencia del sexo del recién nacido en ningún analito. Con los valores encontrados de los indicadores estudiados se obtuvo la caracterización bioquímica de neonatos en Villa Clara. Este conocimiento es un instrumento que puede permitir acceder a un rápido diagnóstico de numerosas afecciones pues, probablemente la alteración de cierto indicador comparada con su valor normal en la sangre del cordón sirva de biomarcador para detectar de forma temprana determinada enfermedad o riesgo de padecer la misma.

Taking into account the fundamental purpose of laboratory medicine, which is to provide the specialist with information that will be useful in the process of medical decision, it has been decided to establish the biochemical profile of healthy newborns of Villa Clara through the quantification of indicators in cord blood and the preliminary estimate of their reference values for our population. Sera samples were used, obtained from umbilical cord blood of 80 healthy newborns (40 females and 40 males) who met the inclusion criteria for this study. Were quantified clinical chemistry parameters (urea, creatinine, alanine aminotransferase, aspartate aminotransferase, total bilirubin, alkaline phosphatase, gamma-glutamyl transferase, cholesterol, triglycerides and VLDL). Immunological parameters (immunoglobulins IgM, IgG and IgA, and C3 and C4 proteins of the complement system) and minerals (iron, copper, zinc, potassium, magnesium and calcium) were quantified. Finally reference values for each parameter were established, taking the interval corresponding to the interpencentil center (95%) interval delimited by the 2.5 and 97.5 percentiles. No statistically significant differences were found depending on the sex of the newborn in any analyte. With the values found for the indicators studied, biochemical characterization of infants in Villa Clara was obtained. This knowledge is a tool that can enable access to rapid diagnosis of many diseases. Probably some indicator change in its value in relation to normal umbilical cord blood can serve as a biomarker for early detection of specific disease or risk.

Levando em consideração o propósito fundamental da medicina laboratorial, que é proporcionar a informação especializada ao especialista, a qual será útil no processo de decisão médica, se decidiu estabelecer o perfil bioquímico de recém-nascidos saudáveis de Villa Clara, através da quantificação de indicadores de sangue do cordão umbilical e a estimativa preliminar de seus valores de referência para esta população. Foi utilizado como amostra o soro obtido do sangue do cordão umbilical de 80 recém-nascidos saudáveis (40 de sexo masculino e 40 de sexo feminino) que preencheram os critérios de inclusão para este estudo. Foram quantificados parâmetros de química clínica (urde la feia, creatinina, alanina aminotransferase, aspartato aminotransferase, bilirrubina total, fosfatase alcalina, gama-glutamil transferase, colesterol, triglicérides e VLDL) imunológicos (imunoglobulinas IgM, IgG e IgA, e as proteínas C3 e C4 do sistema do complemento) e de minerais (ferro, cobre, zinco, sódio, potássio, magnésio e cálcio). Finalmente foram estabelecidos os valores de referência para cada parâmetro, tomando o intervalo entre percentil correspondente ao intervalo central (95%) delimitado pelos percentis 2,5 e 97,5. Não foram encontradas diferenças estatisticamente significativas em função do sexo do recém-nascido em qualquer analito. Com os valores encontrados dos indicadores estudados foi obtida a caracterização bioquímica de neonatos em Villa Clara. Este conhecimento é uma ferramenta que pode permitir o acesso a um diagnóstico rápido de inúmeras doenças, provavelmente a alteração de certo indicador comparada com seu valor normal no sangue do cordão umbilical sirva como um biomarcador para a detecção precoce de uma doença específica ou o risco de sofrer essa doença.

Determinación de valores de referencia para pruebas de coagulación en una población pediátrica / Determination of reference ranges for coagulation tests in a pediatric population / Determinação dos valores de referência para provas de coagulação numa população pediátrica

El sistema hemostático varía a lo largo de las primeras etapas de vida ya que el organismo sufre un proceso dinámico de cambios durante el período de crecimiento. En la literatura existen pocos trabajos sobre valores de referencia en niños de pruebas de hemostasia y por ello la importancia de investigar en el tema. El presente es un trabajo retrospectivo que se realizó sobre 512 niños hasta 17 años que concurrieron al hospital con pedido médico de estudio prequirúrgico para cirugías programadas ambulatorias de los cuales se obtuvieron, de sus historias clínicas, los valores de actividad protrombínica del plasma (APP), tiempo de tromboplastina parcialmente activada (aPTT) y fibrinógeno. Los resultados, teniendo en cuenta el percentilo 97,5, mostraron diferencias significativas para la determinación del APP y del aPTT, no observándose diferencias en la prueba del fibrinógeno. Es importante que cada laboratorio establezca sus propios valores de referencia para estas pruebas, ya que no son extrapolables a los de los adultos. En este estudio se demuestra que el sistema hemostático sufre modificaciones durante la infancia que deben ser tenidas en cuenta para interpretar correctamente los resultados de las pruebas realizadas.

The haemostatic system varies throughout the first stages of life since the body undergoes a dynamic process of changes during the growth period. Little research has been conducted on the reference ranges of haemostasis tests in children; therefore, it is of great significance to investigate this subject. The following study is retrospective and it was conducted on 512 children up to 17 years old that attended the hospital requesting presurgical testing for scheduled ambulatory surgeries. Ranges of plasma prothrombin activity (APP), the activated partial thromboplastin time (aPTT) and fibrinogen were obtained from the patients' medical records. Taking into account the 97.5 percentile, the results showed important differences in APP and aPTT determination but showed no differences in the fibrinogen test. It is important that all laboratories establish their own reference ranges for these tests since they cannot be extrapolated to the ones in adults. This study proves that the haemostatic system undergoes significant changes during infancy which shall be taken into account for the correct interpretation of the results of the tests carried out.

O sistema hemostático varia ao longo das primeiras etapas da vida visto que o organismo sofre um processo dinâmico de alterações durante o periodo de crescimento. Na literatura existem poucos estudos sobre valores de referência de testes de hemostasia em crianças e é por esse motivo que é importante pesquisar sobre o assunto. O presente trabalho é retrospectivo e foi realizado em 512 crianças de até 17 anos que assistiram ao hospital com pedido médico de exame pré-cirúrgico para cirurgias ambulatoriais programadas, de cujos prontuários foram obtidos os valores da atividade protrombínica (APP), tempo de tromboplastina parcialmente ativada (aPTT) e fibrinogênio. Os resultados, levando em consideração o percentil 97,5, mostraram diferenças significativas para a determinação do APP e do aPTT, não encontrando diferenças no teste do fibrinogênio. É importante que cada laboratório estabeleça seus próprios valores de referência para estes testes, visto que não se pode extrapolar para os adultos. Neste estudo é demonstrado que o sistema hemostático sofre modificações na infância as quais devem ser consideradas para interpretar corretamente os resultados dos testes realizados.

Reference range evaluation of complete blood count parameters with emphasis on newer research parameters on the complete blood count analyzer Sysmex XE-2100.

Since the advent of automation in the fi eld of hematological cell counters there has been a constant refi nement of the technology and increase in the number of newer parameters available on CBC analysers. Many novel parameters are being put into routine clinical use and both clinical evaluation and monitoring critically depend on knowledge of laboratory reference ranges. Here, we present reference interval for the Sysmex XE-2100, with emphasis on the novel or newer research parameters. Blood samples from a total of 122 clinically asymptomatic and apparently healthy subjects were evaluated and a fi nal of 100 subjects (54-M, 46-F) were included in the study. A broad spectrum of parameters available with the analyser was assessed and reference ranges for the same evaluated.

Changes in hematologic indices in caucasian and non-caucasian pregnant women in the United States / 대한혈액학회지

BACKGROUND: The objective of this study was to determine if there are differences in common red blood cell (RBC) indices and platelet concentrations during pregnancy and to establish if any observed differences in these parameters were based on the patient's ethnicity. METHODS: From an electronic perinatal database which stores laboratory and clinical information on a large number of births at a regional hospital specializing in obstetrical care, RBC index and platelet concentration data were retrospectively analyzed at various time points throughout pregnancy. RBC index data was collected from 8,277 pregnant women (5,802 Caucasian pregnant women and 2,475 non-Caucasian pregnant women). Platelet concentration data was available from 8252 pregnant women (5,784 Caucasian pregnant women and 2,468 non-Caucasian pregnant women). RESULTS: Hemoglobin (HGB) levels were significantly higher amongst Caucasian women compared to non-Caucasian women (P at least <0.01) starting at 27 weeks gestation and proceeding until term. There was no significant difference in the mean PLT counts between Caucasian and non-Caucasian pregnant women at any point during gestation. CONCLUSION: There are ethnic differences in HGB levels, but not the platelet concentrations, during pregnancy. Based on this finding it would be reasonable to conduct formal prospective studies to determine the clinical significance of this difference and to establish the threshold for diagnosing gestational anemia, especially in pregnant non-Caucasian women.

Avaliação da evolução da área das valvas mitral e tricúspide fetal com ultrassonografia tridimensional / Assessment of the fetal mitral and tricuspid valves areas development by three-dimensional ultrasonography

OBJETIVO: avaliar as áreas das válvulas atrioventriculares (tricúspide e mitral) de fetos normais por meio da ultrassonografia tridimensional (US3D) utilizando o método STIC (spatiotemporal image correlation). MÉTODOS: realizou-se estudo de corte transversal com 141 mulheres entre a 18ª e a 33ª semana de gestação. As medidas dos volumes cardíacos foram obtidas por um transdutor volumétrico transabdominal acoplado ao aparelho Voluson 730 Expert. Utilizou-se como referência o plano de quatro câmaras com a ROI (região de interesse) posicionada a partir dos ventrículos, sendo a área das valvas delimitada manualmente. Para conhecer a correlação das áreas valvulares com a idade gestacional, foram construídos diagramas de dispersão e calculou-se o coeficiente de correlação de Pearson (r). Foram calculadas médias, medianas, desvios padrão (DP), valores máximo e mínimo. Para se determinar intervalos de referência das áreas valvulares em função da idade gestacional, seguiu-se o modelo de regressão linear simples, utilizando o método de Altman, com nível de significância de p<0,05. Para o cálculo da reprodutibilidade intraobservador, utilizou-se o coeficiente de correlação intraclasse (CCI) e o gráfico de Bland-Altman. RESULTADOS: as áreas valvulares tricúspide e mitral se correlacionaram com a idade gestacional (r=0,80 para a tricúspide e r=0,79 para a mitral), sendo que a média aumentou da válvula tricúspide e mitral, respectivamente, de 0,22±0,10 cm² e de 0,23±0,10 cm² na 18º semana para 0,92±0,29 cm² e para 1,08±0,41 cm² na 33º semana de gestação. A reprodutibilidade intraobservador resultou em CCI=0,993 (IC95 por cento 0,987; 0,996), com diferença média de 0,01 cm² (DP±0,2 cm² e IC95 por cento±0,4 cm²). CONCLUSÃO: intervalos de referência para a área das valvares mitral e tricúspide entre a 18ªe a 33ª semana de gestação foram determinados pela US3D e se mostraram altamente reprodutíveis.

PURPOSE: to evaluate the areas of the atrioventricular valves (tricuspid and mitral) of normal fetuses by the use of three-dimensional ultrasound (3DUS) and the spatiotemporal image correlation (STIC) method. METHODS: a cross-sectional study was conducted on 141 women between the 18th and the 33rd week of pregnancy. Cardiac volumes were measured with a volumetric transabdominal transducer attached to the Voluson 730 Expert equipment. The four chamber plane was used as reference, with the region of interest (ROI) positioned from the ventricles, and the area of the valves was obtained manually. To determine the correlation of the areas with gestational age, scatter plots were constructed and the Pearson correlation coefficient (r) was calculated. Means, medians, standard deviations (SD) and maximum and minimum values were calculated. The simple linear regression model was used to determine reference ranges of valve areas according to the gestational age by the Altman method, with the level of significance set at p<0.05. To calculate the intraobserver reproducibility, we used the intraclass correlation coefficient (ICC) and the Bland-Altman graph. RESULTS: the mitral and tricuspid valve areas were correlated to the gestational age (r=0.80 for the tricuspid and r=0.79 for the mitral valve) and the mean value of the tricuspid and mitral valves increased from 0.22±0.10 cm² and 0.23±0.10 cm² on the 18th week to 0.92±0.29 cm² and 1.08±0.41 cm² on the 33rd of pregnancy, respectively. The intraobserver reproducibility resulted in an ICC=0.993 (95 percentCI 0.987; 0.996) and the mean difference was 0.01 cm² (SD±0.2 cm² and CI95 percent±0.4 cm²). CONCLUSION: reference intervals for the areas of the mitral and tricuspid valve between the 18th and the 33rd week of gestation were determined and proved to be highly reproducible.

Intervalos de referência no laboratório clínico: [revisão] / Reference ranges in clinical laboratory: [review]

A definição dos intervalos de referência é tarefa desafiadora para todos os laboratórios clínicos. Entre as possibilidades para estabelecimento desses intervalos destacam-se a definição dos próprios intervalos, a validação dos dados constantes das bulas reagentes e a utilização das informações disponíveis na literatura. A criação de intervalos próprios é a escolha mais desejável para a grande maioria dos testes, pois reflete a condição da população para a qual os eles serão aplicados no dia-a-dia, sendo, porém, a mais trabalhosa e onerosa. A validação dos intervalos fornecidos pelas bulas reagentes e a aplicação dos dados fornecidos pela literatura parecem ser as opções mais freqüentemente utilizadas em nosso meio. A escolha de intervalos adequados de referência é fundamental para que os laboratórios clínicos forneçam informações fidedignas e que os clínicos possam interpretar corretamente os resultados e optar pelas melhores condutas diante da população assistida.

The definition of reference ranges is a challenging task to all clinical laboratories. It is particularly worth mentioning the definition of their own ranges, the validation of data on reagent directions and the use of information available in medical literature as possibilities for the establishment of these ranges. The creation of their own ranges is undoubtedly the most desirable choice in most tests, inasmuch as it reflects the condition of the population on whom they will be applied on a daily basis, yet it is the most laborious and onerous. The validation of ranges offered by the reagent directions and the use of data from medical literature seem to be the most commonly used options in our country. The choice of appropriate reference ranges is essential so that clinical laboratories offer reliable information and physicians interpret the results correctly and choose the best approach towards the assisted population.