Asunto(s)
Alérgenos/inmunología , Proteínas del Huevo/inmunología , Hipersensibilidad/epidemiología , Proteínas de la Leche/inmunología , Contaminantes Atmosféricos/inmunología , Bronquiolitis , Femenino , Alimentos , Humanos , Hipersensibilidad/diagnóstico , Inmunización , Inmunoglobulina E/metabolismo , Lactante , Recién Nacido , Masculino , Noruega/epidemiología , Prevalencia , Pruebas CutáneasRESUMEN
BACKGROUND: The concentration of vitamin K1 in serum or plasma is the most common index for assessing vitamin K status. The aim of this study was to develop and validate a rapid and reliable routine method for quantifying vitamin K1 above 0.1 ng/mL. Semi-automation of a simple sample preparation with fast analysis by supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) was exploited. METHODS: Vitamin K1 was extracted from 250-µL serum samples by the use of protein precipitation and reversed-phase solid-phase extraction (SPE) in 96-well plates and quantified by SFC on a 2.1 × 100 mm Torus 1-Aminoanthracene (1-AA) column in 3.8 min with electrospray ionization-tandem mass spectrometry (MS/MS) detection. RESULTS: This method shows good linearity in the concentration range of 0.1-50 ng/mL with a correlation coefficient of R2 >0.999. Imprecision was satisfactory, with repeatability and reproducibility <10% CV. The lower limit of the measuring interval was 0.1 ng/mL, and no systematic bias was observed for the method, which used vitamin K1-d7 as internal standard. Recovery of vitamin K1 in external quality controls was satisfactory compared to other laboratories participating in the external quality assurance scheme. The method is currently in routine use for analysis of serum samples. CONCLUSIONS: The method allows high-throughput reliable determination of vitamin K1 in serum in the range 0.1-50 ng/mL.
Asunto(s)
Electroforesis Capilar , Proteínas de Mieloma/análisis , Transferrina/análogos & derivados , Anciano , Estudios de Casos y Controles , Humanos , Inmunoglobulina A/análisis , Isotipos de Inmunoglobulinas/análisis , Inmunoglobulina M/análisis , Hallazgos Incidentales , Gammopatía Monoclonal de Relevancia Indeterminada/metabolismo , Gammopatía Monoclonal de Relevancia Indeterminada/patología , Estudios Retrospectivos , Transferrina/análisisRESUMEN
BACKGROUND: HbA1c methods may be prone to interference by the presence of haemoglobin variants. In contrast to the variant mode of the HbA1c method on the Tosoh G7 instrument, the literature lacks investigations of haemoglobin variant interference with the standard mode. The current study sought to investigate whether different haemoglobin variants interfere with the Tosoh G7 standard mode HbA1c method, and whether present haemoglobin variants are identifiable on respective chromatograms. METHODS: Samples routinely analyzed for HbA1c and suspected of having haemoglobin variants (N = 103) were included. HbA1c was measured on a Tosoh G7 in standard mode (Tosoh Corporation, Japan), and on the DCA Vantage (Siemens, Germany). Haemoglobin variants were identified using the VARIANT(™)ß-Thalassemia Short Program (Bio-Rad Laboratories, Hercules, CA, USA) and by DNA sequencing. RESULTS: The Tosoh G7 in standard mode measured significantly lower HbA1c results (between 1.0 and 2.5 percentage points absolute bias corresponding to between 11 and 27 mmol/mol, p < 0.001) in samples in which common haemoglobin variants (HbS, HbC, HbD or HbE) were present (n = 61). No significant difference in HbA1c (0.04 percentage points, p = 0.74) was found between Tosoh G7 standard mode and DCA Vantage in samples in which haemoglobin variants were absent (n = 36). In contrast to HbS and HbD, HbE and HbC trait could be identified on respective chromatograms. CONCLUSION: The presence of common haemoglobin variants results in falsely low HbA1c measurements on the Tosoh G7 in standard mode. HbS and HbD trait are not identifiable on respective haemoglobin chromatograms.
Asunto(s)
Hemoglobina Glucada/análisis , Pruebas Hematológicas/métodos , Pruebas Hematológicas/normas , Cromatografía Líquida de Alta Presión , Humanos , Juego de Reactivos para Diagnóstico , Estándares de ReferenciaAsunto(s)
Diabetes Mellitus Tipo 2/diagnóstico , Hemoglobina Glucada/metabolismo , Hemoglobinas Anormales/metabolismo , Glucemia , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/genética , Reacciones Falso Negativas , Ayuno , Hemoglobinas Anormales/genética , Humanos , Masculino , Persona de Mediana Edad , Técnicas de Diagnóstico Molecular , Mutación Puntual , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Lactose intolerance afflicts 5-10% of the population in western Europe, but is very common (up to 90%) in the southern hemisphere. Traditional analysis methods are based on lactose intake followed by determination of blood glucose concentration or exhaled H 2 and CH 4 . In many diagnostic laboratories, single nucleotide polymorphism (SNP) analysis on C/T-13910 has been introduced as a replacement for the traditional lactose intolerance testing. Homozygozity for the C-allele of this SNP results in very low or absent lactase enzyme activity. We have compared our present routine test (blood glucose measurements) to genetic SNP testing for C/T-13910. MATERIAL AND METHODS: Blood glucose measurements (after intake of lactose) and genotyping of C/T-13910 were performed on 137 adult participants after they had given informed consent. The maximal difference from fasting blood glucose was compared with real-time PCR analysis of C/T-13910. RESULTS AND INTERPRETATION: Lactose intolerance using blood glucose was positive for 20.4% of those tested; for the genetic test the corresponding result was 17.5%. The correlation between the methods was strong (90%) with a kappa-statistics index of 0.67 (0.51 - 0.83, 95% CI). Our results indicate that the genetic test for C/T-13910 complements the traditional phenotype measurements.