Resistencia a la insulina tipo A, nueva mutación del gen del receptor de la insulina descrita / Resistance to type A insulin: A new mutation of the receptor gene of the insulin described

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Hipoparatiroidismo y trastorno del desarrollo sexual: una asociación inusual / Hypoparathyroidism and disorder of sex development: A rare association

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Serum sample containing endogenous antibodies interfering with multiple hormone immunoassays. Laboratory strategies to detect interference.

OBJECTIVES: Endogenous antibodies (EA) may interfere with immunoassays, causing erroneous results for hormone analyses. As (in most cases) this interference arises from the assay format and most immunoassays, even from different manufacturers, are constructed in a similar way, it is possible for a single type of EA to interfere with different immunoassays. Here we describe the case of a patient whose serum sample contains EA that interfere several hormones tests. We also discuss the strategies deployed to detect interference. SUBJECTS AND METHODS: Over a period of four years, a 30-year-old man was subjected to a plethora of laboratory and imaging diagnostic procedures as a consequence of elevated hormone results, mainly of pituitary origin, which did not correlate with the overall clinical picture. RESULTS: Once analytical interference was suspected, the best laboratory approaches to investigate it were sample reanalysis on an alternative platform and sample incubation with antibody blocking tubes. Construction of an in-house 'nonsense' sandwich assay was also a valuable strategy to confirm interference. In contrast, serial sample dilutions were of no value in our case, while polyethylene glycol (PEG) precipitation gave inconclusive results, probably due to the use of inappropriate PEG concentrations for several of the tests assayed. CONCLUSIONS: Clinicians and laboratorians must be aware of the drawbacks of immunometric assays, and alert to the possibility of EA interference when results do not fit the clinical pattern.

Leptina e insulinoterapia en la diabetes gestacional / Leptin and insulin therapy in gestational diabetes

Introducción: Se han publicado varios trabajos que implican a la leptina (L) en diversos procesos metabólicos, entre ellos la diabetes gestacional (DG) y otras alteraciones del embarazo como la preeclampsia y el retraso de crecimiento intrauterino. Se ha observado que la concentración de L en plasma es superior en gestantes diabéticas que en gestantes sanas. Objetivo: Valorar si la L puede ser un parámetro bioquímico de utilidad en pacientes con DG a la hora de predecir la necesidad de tratamiento insulínico desde el momento mismo del diagnóstico. Pacientes y método: Cincuenta mujeres diagnosticadas de DG entre las semanas 28 y 32 con: media ± desviación estándar de edad, 34,4 ± 4,5 años; IMC, 25,4 ± 2,14, y L, 48,5 ± 16 ng/ml. Fueron separadas en 2 grupos: uno con criterios de insulinización, formado por 24 pacientes, y otro que no precisó insulina, formado por 26. Los criterios de inclusión fueron: presentar un IMC > 22,5 y 40 ng/ml. Conclusiones: Con la cautela de precisar más estudios y con mayor número de pacientes, se puede indicar que la L es útil como parámetro bioquímico que nos ayude a predecir la necesidad de tratamiento insulínico en pacientes diagnosticadas de DG

Introduction: Various studies have implicated leptin in several metabolic processes, among them gestational diabetes (GD) and other pregnancy-associated alterations such as preeclampsia and uterine growth retardation. Plasma leptin levels have been observed to be higher in diabetic pregnant women than in healthy pregnant women. Objective: To evaluate whether leptin could be a useful biochemical marker in patients with GD to predict the need for insulin therapy at diagnosis. Patients and method: Fifty women with a diagnosis of GD between 28 and 32 weeks of pregnancy [mean age, 34.4 ± 4.5 years; body mass index (BMI), 25.4 ± 2.14, and leptin level, 48.5 ± 16 ng/ml] were studied. The women were divided into two groups: one group was composed of 24 women with criteria for insulin therapy and the other group consisted of 26 women not requiring insulin therapy. The inclusion criteria were BMI greater than 22.5 and lower than 27 and biochemical determination between weeks 28 and 32. Results: Maternal plasma leptin levels were significantly higher in the group requiring insulin. No differences were found in the mean age of the patients or in BMI. The odds ratio predicting the need for insulin therapy during pregnancy was 6 in pregnant women with a leptin level higher than 40 ng/ml. Conclusions: Leptin determination could be useful in predicting the need for insulin therapy in patients with GD. However, further studies with a larger number of patients are required to confirm our findings