Interference of Hb D-Los Angeles on the measurement of glycated hemoglobin. A case report / Interferencia en la medida de la hemoglobina glicada en presencia de Hb D-Los Angeles. Presentación de un caso clínico

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Hemoglobin Le Lamentin in the province of Albacete, Spain: Discovery of 32 cases.

OBJECTIVES: Hemoglobin Le Lamentin (α20(B1)His→Gln) is a ubiquitous variant that has been previously described in a small number of isolated patients. We report the incidental observation of Hb Le Lamentin in a large population from the province of Albacete, in southeastern Spain. Our study investigates possible reasons for the elevated number of carriers of this variant and its implications for the management of diabetes in our region. DESIGN & METHODS: The subjects are 32 diabetic patients whose hemoglobin displayed an unusual peak while they were being tested for glycated hemoglobin at the laboratory of the University General Hospital of Albacete over a 3-year period. Measurements were made by high performance liquid chromatography using a Variant™ II Turbo Kit-2.0, and subsequently the samples of the 32 patients with anomalous peaks were sent to the Hospital Clínico San Carlos (Madrid, Spain) for molecular characterization of any Hb variants. RESULTS: Molecular studies revealed 31 out of 32 patients heterozygous for Le Lamentin, and in one of them, Hb City of Hope was associated with Hb Le Lamentin. The remaining patient was homozygous for the Le Lamentin mutation. Additionally, most patients were native to the northeastern half of the province of Albacete and were unrelated. CONCLUSIONS: Our study describes the largest finding to date of hemoglobin Le Lamentin in a sample of patients. The fact that our region has been perpetually depopulated, with a population that has remained stable in small localities over the centuries, may have favored the survival of the mutation. Since the presence of this variant underestimates the true value of glycated hemoglobin measured by HPLC, it is necessary to systematically review chromatograms.

Preanalítica de orina de 24 horas: qué hacemos y qué deberíamos hacer / 24-Hour urine pre-analytical phase: what we do and what we should do

Introducción. Ante la necesidad de estandarizar los procedimientos de recogida, transporte, manejo y análisis de muestras de orina de 24 h, se han elaborado guías internacionales con una serie de recomendaciones que deberían ser adaptadas a cada laboratorio según sus circunstancias. Objetivo. Conocer el grado de cumplimiento de estas recomendaciones en laboratorios españoles. Material y métodos. Se realizó una encuesta a través de la página web de la Sociedad Española de Bioquímica Clínica y Patología Molecular sobre los diferentes procesos preanalíticos en el manejo de la orina de 24 h. Resultados. Se obtuvieron respuestas de 50 laboratorios, dos de los cuales no eran españoles. Aunque mayoritariamente los laboratorios proporcionan información acerca de la recogida de la muestra, existe variabilidad en la forma de hacerlo. Estas diferencias se observan en aspectos como el acceso de los pacientes a los contenedores de recogida de orina con y sin conservante, la forma de entregar la muestra, el registro de la información asociada y los criterios de rechazo de una muestra no recogida de forma correcta. Conclusiones. Existe variabilidad en el cumplimiento de las recomendaciones internacionales. Un posible sesgo de esta encuesta es que los participantes en ella sean los que más motivados estén por este tema, y por tanto más fieles al cumplimiento de estas normas, por lo que la variabilidad detectada podría ser aún mayor. Finalmente, se revisan las principales recomendaciones para la estandarización de todo el proceso, con el fin de obtener una muestra de calidad que asegure unos buenos resultados (AU)

Introduction. Given the need to standardise procedures for the collection, transportation, handling, and analysis of 24-hour urine specimens, international guidelines have been developed with a series of recommendations that should be adapted to each laboratory depending on its circumstances. Objective. To determine the level of compliance to these recommendations in Spanish laboratories. Material and methods. A survey was carried out, through the website of the Spanish Society of Clinical Biochemistry and Molecular Pathology, on the different pre-analytical procedures in the management of 24hour urine specimens. Results. A total of 50 laboratories responded, two of which were not Spanish. Although most laboratories provide information about the collection of the specimen, there is variability in how this is done. Differences were observed in areas such as, patient access to containers for collecting urine without preservative, how to deliver the specimen, recording the associated information, and rejection criteria of a specimen not collected correctly. Conclusions. There is variability in compliance with international recommendations. A possible bias of the survey is that the participants were those who are more motivated by this issue, and therefore more faithful compliance with these standards, thus the variability detected could be even higher. Finally, the main recommendations for the standardisation of the entire procedure is reviewed in order to obtain a specimen quality to ensure good results (AU)

Different forms of Hb Le Lamentin. An unexpected finding in Hba1c quantification.

OBJECTIVES: Glycated hemoglobin (HbA1c) is accepted as the most trusted marker for monitoring patients with diabetes mellitus. Ion-exchange high-performance liquid chromatography (HPLC) is one of the most widely used methods for HbA1c analysis. The presence of a hemoglobin variant can interfere with HbA1c quantification, requiring other analyses to clarify the results.Herein, we present two cases of Hb Le Lamentin, which, although they were the same variant, were thought to correspond to different hemoglobinopathies because of their percentages. DESIGN AND METHODS: Two male patients presented with an anomalous peak between HbA1c and HbA0 during a routine analysis of HbA1c using ion-exchange HPLC (Variant™ II Turbo).The hemoglobin variants were studied using capillary zone electrophoresis with the Sebia system, and the globin chains were analyzed by reverse-phase HPLC. A genetic analysis was performed using automated sequencing of the α2 and ß genes. RESULTS: In this work, we describe the first case of homozygous Hb Le Lamentin and the first double-heterozygous case of Hb Le Lamentin/Hb City of Hope. CONCLUSIONS: Although the presence of these variants does not lead to clinical anomalies, it also does not affect hematologic parameters. The variants have an impact on the determination of glycated hemoglobin levels using ion-exchange HPLC because the retention time interferes with the elution time of HbA1c, resulting in a falsely reduced value. Therefore, it is necessary to either recalculate the result or use another measurement method.

Current use of equations for estimating glomerular filtration rate in Spanish laboratories.

INTRODUCTION: In 2006 the Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC) and the Spanish Society of Nephrology (S.E.N.) developed a consensus document in order to facilitate the diagnosis and monitoring of chronic kidney disease with the incorporation of equations for estimating glomerular filtration rate (eGFR) into laboratory reports. The current national prevalence of eGFR reporting and the degree of adherence to these recommendations among clinical laboratories is unknown. METHODS: We administered a national survey in 2010-11 to Spanish clinical laboratories. The survey was through e-mail or telephone to laboratories that participated in the SEQC’s Programme for External Quality Assurance, included in the National Hospitals Catalogue 2010, including both primary care and private laboratories. RESULTS: A total of 281 laboratories answered to the survey. Of these, 88.2% reported on the eGFR, with 61.9% reporting on the MDRD equation and 31.6% using the MDRD-IDMS equation. A total of 42.5% of laboratories always reported serum creatinine values, and other variables only when specifically requested. Regarding the way results were presented, 46.2% of laboratories reported the exact numerical value only when the filtration rate was below 60mL/min/1.73m2, while 50.6% reported all values regardless. In 56.3% of the cases reporting eGFR, an interpretive commentary of it was enclosed. CONCLUSIONS: Although a high percentage of Spanish laboratories have added eGFR in their reports, this metric is not universally used. Moreover, some aspects, such as the equation used and the correct expression of eGFR results, should be improved.