Reference Standards for C-Peptide in Korean Population: A Korean Endocrine Hormone Reference Standard Data Center Study.

BACKGRUOUND: The Korean Endocrine Hormone Reference Standard Data Center (KEHRS DC) has created reference standards (RSs) for endocrine hormones since 2020. This study is the first of its kind, wherein the KEHRS DC established RSs for serum Cpeptide levels in a healthy Korean population. METHODS: Healthy Korean adults were recruited from May 2021 to September 2023. After excluding participants according to our criteria, serum samples were collected; each participant could then choose between fasting glucose only or fasting glucose plus an oral glucose tolerance test (OGTT). If their sample showed high glucose (≥100 mg/dL) or hemoglobin A1c (HbA1c) (≥5.70%), their C-peptide levels were excluded from analyzing the RSs. RESULTS: A total of 1,532 participants were recruited; however, only the data of 1,050 participants were analyzed after excluding those whose samples showed hyperglycemia or high HbA1c. Post-30-minute OGTT data from 342 subjects and post-120-minute OGTT data from 351 subjects were used. The means±2 standard deviations and expanded uncertainties of fasting, post-30-minute and 120-minute OGTT C-peptide levels were 1.26±0.82 and 0.34-3.18, 4.74±3.57 and 1.14-8.33, and 4.85±3.58 and 1.25-8.34 ng/mL, respectively. Serum C-peptide levels correlated with obesity, serum glucose levels, and HbA1c levels. CONCLUSION: The RSs for serum C-peptide levels established in this study are expected to be useful in both clinical and related fields.

Plasma Glucose Concentrations in Different Sampling Tubes Measured on Different Glucose Analysers.

INTRODUCTION: The German Diabetes Association recommends using sampling tubes with citrate and fluoride additives to diagnose diabetes by oral glucose tolerance test to inhibit glycolysis. The effect of different tubes on measurement results was assessed. MATERIALS AND METHODS: In a first study, an oral glucose tolerance test was performed on 41 participants without anamnestically known diabetes. Venous blood was sampled in two different tubes with citrate/fluoride additives from different manufacturers and one with only lithium-heparin additive. A second study with 42 participants was performed to verify the initial results with an adapted design, in which a third tube with citrate buffer was used, and glucose measurements were performed on two additional devices of another analyser model. Samples were centrifuged either immediately (<5 min incubation time) or after 20 min or 4 h. All glucose measurements were performed in plasma. Glucose concentrations in lithium-heparin tubes with<5 min incubation time served as baseline concentrations. RESULTS: In the first study, glucose concentrations in one of the citrate/fluoride tubes were similar to the baseline. In the other citrate/fluoride tube, markedly lower concentrations (approximately - 5 mg/dL (- 0.28 mmol/L)) were measured. This was reproduced in the verification study for the same analyser, but not with the other analyser model. Lithium-heparin tubes centrifuged after 20 and 240 min showed systematically lower glucose concentrations. CONCLUSIONS: The results confirm that glycolysis can be effectively inhibited in citrate/fluoride-containing sampling tubes. However, glucose measurement results of one analyser showed a relevant negative bias in tubes containing liquid citrate buffer.

Two criteria of oral glucose tolerance test to diagnose gestational diabetes mellitus

SUMMARY OBJECTIVE To evaluate two different criteria, one or two cut-off values, of oral glucose tolerance test with 75g of glucose for the diagnosis of gestational diabetes mellitus. METHODS A cross-sectional study involving 120 records of pregnant women who received prenatal care at the service of a Brazilian university was carried out. Bivariate analysis of obstetric and perinatal outcomes was performed using the chi-square test. RESULTS Considering criterion I, 12.5% of patients were diagnosed with gestational diabetes mellitus. Patients were 3.57 times more likely to have a large fetus for the gestational age at birth (p=0.038). Using criterion II, gestational diabetes mellitus was diagnosed in 5.8% of patients, macrosomia was 7.73 times more likely to be found in the presence of gestational diabetes mellitus (p=0.004), and a large fetus for the gestational age at birth was 8.17 times more likely (p=0.004). CONCLUSIONS There was a difference in the prevalence of gestational diabetes mellitus between the two criteria analyzed. The new criterion proposed increased prevalence.

RESUMO OBJETIVO Avaliar dois critérios distintos, um ou dois valores de corte, do teste oral de tolerância à glicose com 75 g de glicose para o diagnóstico de diabetes mellitus gestacional. Métodos Estudo transversal envolvendo 120 prontuários de gestantes que realizaram pré-natal em um ambulatório de uma universidade brasileira. Análise bivariada dos resultados obstétricos e perinatais foi realizada pelo teste do qui-quadrado. Resultados Considerando o critério I, 12,5% das pacientes foram diagnosticadas com diabetes mellitus gestacional. As pacientes apresentaram uma chance 3,57 maior de ter um feto grande para a idade gestacional (p=0,038). Utilizando o critério II, o diabetes mellitus gestacional foi diagnosticado em 5,8% das pacientes. Mediante esse critério diagnóstico, a chance de macrossomia foi 7,73 vezes mais provável na presença de diabetes mellitus gestacional (p=0,004) e a chance de um feto grande para a idade gestacional foi 8,17 vezes maior de ocorrer (p=0,004). Conclusões Observou-se diferença na prevalência de diabetes melittus gestacional entre os dois critérios analisados, sendo que o novo critério proposto aumentou a prevalência.

Validity of Glycated Hemoglobin in Screening and Diagnosing Type 2 Diabetes Mellitus in Chinese Subjects

BACKGROUND/AIMS: The application of glycated hemoglobin (HbA1c) for the diagnosis of diabetes is currently under extensive discussion. In this study, we explored the validity of using HbA1c as a screening and diagnostic test in Chinese subjects recruited in Nanjing, China. METHODS: In total, 497 subjects (361 men and 136 women) with fasting plasma glucose (PG) > or = 5.6 mmol/L were recruited to undergo the oral glucose tolerance test (OGTT) and HbA1c test. Plasma lipid, uric acid, and blood pressure were also measured. RESULTS: Using a receiver operating characteristic curve, the optimal cutoff point of HbA1c related to diabetes diagnosed by the OGTT was 6.3%, with a sensitivity and specificity of 79.6% and 82.2%, respectively, and the area under the curve was 0.87 (95% confidence interval, 0.83 to 0.92). A HbA1c level of 6.5% had a sensitivity and specificity of 62.7% and 93.5%, respectively. When comparing the HbA1c > or = 6.5% or OGTT methods for diagnosing diabetes, the former group had significantly higher HbA1c levels and lower levels of fasting and 2-hour PG than the latter group. No significant difference was observed in the other metabolism indexes between the two groups. CONCLUSIONS: Our results suggest that HbA1c > or = 6.5% has reasonably good specificity for diagnosing diabetes in Chinese subjects, which is in concordance with the American Diabetes Association recommendations.

Análise crítica do uso dos índices do Homeostasis Model Assessment (HOMA) na avaliação da resistência à insulina e capacidade funcional das células-beta pancreáticas: [revisão] / Critical analysis on the use of the homeostasis hodel assessment (HOMA) indexes in the evaluation of the insulin resistance and the pancreatic beta cells functional capacity: [review]

A disfunção das células-beta e a resistência insulínica são anormalidades metabólicas inter-relacionadas na etiologia do diabetes tipo 2. Em diversos países, tem sido observado o aumento da prevalência de obesidade e diabetes em associação com a presença da resistência insulínica. Nesse contexto, é útil a mensuração da resistência insulínica e da capacidade funcional das células-beta nos indivíduos. Os índices Homeostasis Model Assessment (HOMA) têm sido amplamente utilizados, representando uma das alternativas para avaliação desses parâmetros, principalmente por figurarem um método rápido, de fácil aplicação e de menor custo. Esta revisão discute sobre a origem e a evolução dos índices HOMA, bem como as particularidades do método, abordando aspectos relacionados à sua validação e aos pontos de corte existentes para sua interpretação.

Beta-cell dysfunction and insulin resistance are interrelated metabolic abnormalities in the aetiology of Type 2 Diabetes. In several countries, increases in the prevalence of obesity and diabetes have been observed in association with the presence of insulin resistance. In this context, measurement of insulin resistance and beta-cell function is useful. The HOMA indexes (Homeostasis Model Assessment) have been widely used, representing an alternative for the evaluation of these parameters, particularly as a fast, easy and cheap method. This review discusses the origin and evolution of the HOMA index, as well as details of the method, analyzing features related to its validation and the cutoff limits for its interpretation.

Evaluación crítica del test de tolerancia oral a la glucosa para el diagnóstico de resistencia insulínica en pacientes con síndrome de ovario poliquístico / Critical evaluation of the oral glucose tolerance test for the diagnosis of insulin resistance in patients with polycystic ovary syndrome

El test de tolerancia oral a la glucosa (TTOG) es el más frecuentemente utilizado en la práctica clínica para el diagnóstico de resistencia insulínica (RI). El objetivo del presente trabajo fue la evaluación de la utilidad de los índices basales e índices TTOG, en mujeres con síndrome de ovario poliquístico (SOP) y del valor predictivo de los índices basales sobre la glucemia a los 120 minutos postprandial (G 120). Se estudiaron 114 pacientes con diagnóstico de SOP y 29 mujeres normales. A todas se les realizó un TTOG. Se dosó insulina y glucosa séricas cada 30 min durante las 2 horas del test y se determinaron los siguientes índices: Indices basales: GLU/lNS (glucemia en ayunas / insulinemia en ayunas), HOMA (modelo homeostático) y QUICKI (índice cuantitativo de sensibilidad insulínica) e índices TTOG: AI (área bajo la curva de insulina) e ISI composite (índice de sensibilidad insulínica). Se observaron correlaciones significativas entre los índices basales y los índices TTOG. Hubo 9 pruebas con índices basales normales que presentaban índice TTOG patológicos. Ninguna paciente con niveles de insulina menores a 9.9 Ul/ml presentó RI, mientras que todas las pacientes con niveles de insulina mayores a 18.4 Ul/ml tuvieron RI. Catorce pacientes (10.5%) presentaron G 120 ³ a 140 mg%. En 4 de los 14 casos (12.2%), los valores basales no hicieron sospechar la posibilidad del diagnóstico de hiperglucemia post prandial. En conclusión, en pacientes con SOP, los índices basales son útiles para diagnosticar RI. Proponemos realizar TTOG para diagnóstico de RI en aquellas pacientes que presenten insulinemias en ayunas entre 9.9 y 18.4 Ul/ml. En pacientes con SOP, se recomienda la evaluación periódica de la G 120.

Oral glucose tolerance test (OGTT) is the most commonly used method to evaluate insulin resistance (IR) in the clinical practice. Our objective was to evaluate the diagnostic utility of fasting tests compared with OGTT tests in women with PCO, and the ability of fasting tests to detect postprandial hyperglycemia. One hundred fourteen women with PCO and 29 normal women were evaluated by a 2 hours OGTT. Fasting plasma insulin (INS) and glucose were measured during the test. GLU:INS ratio (r) (fasting glucose/fasting insulin), HOMA (homeostatic model assessment), QUICKI (quantitative insulin sensitivity check index) (fasting tests), as well as the AUCI (area under the curve of INS) and ISI composite (ISI) (insulin sensitivity index) (OGTT tests), were determined. A significant correlation between fasting tests and OGTT tests was found. Normal fasting tests with abnormal OGTT tests were found in 9 patients. No patient with fasting insulin levels less than 9.9 UI/ml were IR, and all women with fasting insulin levels over 18.4 UI/ml were classified as having IR. We found glucose levels 120 min post glucose load (G 120) ³ 140 mg/dl in 14 patients (12.2%). Fasting glucose and insulin levels and the fasting tests, were poor predictors of impaired glucose tolerance (IGT) and type 2 diabetes (DBT 2). Thus, fasting tests are useful in the diagnostic of IR in PCO patients. OGTT is necessary when the fasting insulin levels range between 9.9 and 18.4 UI/ml. Women with PCO should undergo periodic screening for abnormal glucose tolerance.

Evaluación crítica del test de tolerancia oral a la glucosa para el diagnóstico de resistencia insulínica en pacientes con síndrome de ovario poliquístico / Critical evaluation of the oral glucose tolerance test for the diagnosis of insulin resistance in patients with polycystic ovary syndrome

El test de tolerancia oral a la glucosa (TTOG) es el más frecuentemente utilizado en la práctica clínica para el diagnóstico de resistencia insulínica (RI). El objetivo del presente trabajo fue la evaluación de la utilidad de los índices basales e índices TTOG, en mujeres con síndrome de ovario poliquístico (SOP) y del valor predictivo de los índices basales sobre la glucemia a los 120 minutos postprandial (G 120). Se estudiaron 114 pacientes con diagnóstico de SOP y 29 mujeres normales. A todas se les realizó un TTOG. Se dosó insulina y glucosa séricas cada 30 min durante las 2 horas del test y se determinaron los siguientes índices: Indices basales: GLU/lNS (glucemia en ayunas / insulinemia en ayunas), HOMA (modelo homeostático) y QUICKI (índice cuantitativo de sensibilidad insulínica) e índices TTOG: AI (área bajo la curva de insulina) e ISI composite (índice de sensibilidad insulínica). Se observaron correlaciones significativas entre los índices basales y los índices TTOG. Hubo 9 pruebas con índices basales normales que presentaban índice TTOG patológicos. Ninguna paciente con niveles de insulina menores a 9.9 Ul/ml presentó RI, mientras que todas las pacientes con niveles de insulina mayores a 18.4 Ul/ml tuvieron RI. Catorce pacientes (10.5%) presentaron G 120 ³ a 140 mg%. En 4 de los 14 casos (12.2%), los valores basales no hicieron sospechar la posibilidad del diagnóstico de hiperglucemia post prandial. En conclusión, en pacientes con SOP, los índices basales son útiles para diagnosticar RI. Proponemos realizar TTOG para diagnóstico de RI en aquellas pacientes que presenten insulinemias en ayunas entre 9.9 y 18.4 Ul/ml. En pacientes con SOP, se recomienda la evaluación periódica de la G 120. (AU)

Oral glucose tolerance test (OGTT) is the most commonly used method to evaluate insulin resistance (IR) in the clinical practice. Our objective was to evaluate the diagnostic utility of fasting tests compared with OGTT tests in women with PCO, and the ability of fasting tests to detect postprandial hyperglycemia. One hundred fourteen women with PCO and 29 normal women were evaluated by a 2 hours OGTT. Fasting plasma insulin (INS) and glucose were measured during the test. GLU:INS ratio (r) (fasting glucose/fasting insulin), HOMA (homeostatic model assessment), QUICKI (quantitative insulin sensitivity check index) (fasting tests), as well as the AUCI (area under the curve of INS) and ISI composite (ISI) (insulin sensitivity index) (OGTT tests), were determined. A significant correlation between fasting tests and OGTT tests was found. Normal fasting tests with abnormal OGTT tests were found in 9 patients. No patient with fasting insulin levels less than 9.9 UI/ml were IR, and all women with fasting insulin levels over 18.4 UI/ml were classified as having IR. We found glucose levels 120 min post glucose load (G 120) ³ 140 mg/dl in 14 patients (12.2%). Fasting glucose and insulin levels and the fasting tests, were poor predictors of impaired glucose tolerance (IGT) and type 2 diabetes (DBT 2). Thus, fasting tests are useful in the diagnostic of IR in PCO patients. OGTT is necessary when the fasting insulin levels range between 9.9 and 18.4 UI/ml. Women with PCO should undergo periodic screening for abnormal glucose tolerance. (AU)

Comparison between 100-g glucose tolerance test and two other screening tests for gestational diabetes: combined fasting glucose with risk factors and 50-g glucose tolerance test

CONTEXTO E OBJETIVO: A falta de consenso sobre os protocolos de rastreamento e diagnóstico do diabetes gestacional, associada às dificuldades na realização do teste oral simplificado do diabete gestacional (o teste de tolerância a 100 g de glicose, considerado padrão-ouro) justificam a comparação com alternativas. O objetivo deste trabalho é comparar o teste padrão-ouro a dois testes de rastreamento: associação de glicemia de jejum e fatores de risco (GJ + FR) e o teste oral simplificado de tolerância a 50 g de glicose (TTG 50 g), com o teste de tolerância a 100 g de glicose (TTG 100 g).TIPO DE ESTUDO E LOCAL: Estudo de coorte longitudinal, prospectivo, realizado no Serviço de Ginecologia e Obstetrícia do Hospital Universitário da Universidade Federal de Mato Grosso do Sul. MÉTODOS: 341 gestantes foram submetidas aos três testes. Calcularam-se os índices de sensibilidade (S), especificidade (E), valores preditivos (VPP e VPN), razões de probabilidade (RPP e RPN) e resultados falsos (FP e FN), positivos e negativos da associação GJ + FR e do TTG 50 g em relação ao TTG 100 g. Compararam-se as médias das glicemias de uma hora pós-sobrecarga (1hPS) com 50 e 100 g. Na análise estatística, empregou-se o teste t de Student, com limite de significância de 5%. RESULTADOS: A associação GJ + FR encaminhou mais gestantes (53,9%) para a confirmação diagnóstica que o TTG 50 g (14,4%). Os dois testes foram equivalentes nos índices de S (86,4 e 76,9%), VPN (98,7 e 98,9%), RPN (0,3 e 0,27) e FN (15,4 e 23,1%). As médias das glicemias 1hPS foram semelhantes, 106,8 mg/dl para o TTG 50 g e 107,5 mg/dl para o TTG 100 g. CONCLUSÕES: Os resultados da eficiência diagnóstica associados à simplicidade, praticabilidade e custo referendaram a associação GJ + FR como o mais adequado para o rastreamento. A equivalência das glicemias de 1hPS permitiram a proposição de um novo protocolo de rastreamento e diagnóstico do diabete gestacional, com menores custo e desconforto.

Análise dos critérios diagnósticos dos distúrbios do metabolismo de glicose e variáveis associadas à resistência insulínica / Diagnostic criteria of the glucose metabolism disorders and variables associated to insulin resistence

Os critérios diagnósticos dos distúrbios do metabolismo de glicose foram estabelecidos pela Organizaçäo Mundial de Saúde (OMS)/National Diabetes Data Group (NDDG) no início da década de 1980. Em 1997, a American Diabetes Association (ADA) sugeriu novos critérios diagnósticos, baseados na interpretaçäo da glicemia de jejum. Neste estudo, 56 indivíduos foram submetidos ao teste de tolerância à glicose oral (oGTT) (75g) e aplicamos ambos os critérios diagnósticos para estimar a prevalência de distúrbios de metabolismo de glicose. Dos 56 indivíduos, 11 (19,6 % - grupo 1) foram considerados intolerantes pelos critérios da OMS/NDDG e seis (10,7 % - grupo 2), como glicemia de jejum alterada (GJA) pelos novos critérios da ADA. Comparamos variáveis clínicas e bioquímicas (idade, índice de massa corporal, pico de insulina durante o oGTT, área sob a curva de insulina durante o oGTT e concentrações séricas basais da proteína carreadora dos fatores de crescimento insulina-símiles 1 (IGFBP-1) entre ambos os grupos, näo observando diferença significativa em nenhuma das variáveis (43 ± 13 x 46 ± 4,4 anos, 29,5 ± 3,2 x 27,2 ± 2,6kg/m², 153,7 ± 100,7 x 171,3 ± 145,6µUI/ml, 12.040 ± 8.488 x 13.970 ± 12.170 e 14,4 ± 9,3 x 19,4 ± 11,8ng/ml, respectivamente, p = NS). Entretanto, quando comparamos estas mesmas variáveis entre o grupo de indivíduos considerados normais pelos critérios da ADA e intolerantes pelos critérios da OMS/NDDG (n = 8, grupo 3) e o grupo de indivíduos considerados normais por ambos os critérios (n = 42, grupo 4), observamos que näo houve também diferença em relaçäo à idade (42 ± 15 x 38 ± 10 anos, respectivamente, NS); entretanto o grupo 3 apresenta índice de massa corporal (IMC) (29,5 ± 3,9 x 24,5 ± 3,5kg/m², respectivamente, p < 0,02), pico de insulina durante o oGTT (115,2 ± 29,1 x 84,4 ± 56,5µUI/ml, respectivamente, p < 0,02) e área sob a curva de insulina durante o oGTT (9.112 ± 2.323 x 6.649 ± 4.438, respectivamente, p < 0,007) com valores médios superiores ao grupo 4. O grupo 3 apresentou ainda concentrações séricas basais de IGFBP-1 com valores em média inferiores ao grupo 4 (14,9 ± 10,1 x 28,9 ± 17,6ng/ml, respectivamente, p < 0,03)