Endocrine Abstracts

Background: The 1 mg overnight dexamethasone suppression test (ONDST) is recommended as a first-line test for the investigation of Cushing Syndrome. Measurement of dexamethasone alongside cortisol in a 9am serum sample has been credited with improving diagnostic sensitivity of the test. Previous studies have also looked at the utility of salivary dexamethasone and have observed poor correlation with serum dexamethasone. Herein we introduce the concept of measuring 11-dehydrode...

Background: 5-hydroxyindole acetic acid (5-HIAA), a metabolite of serotonin, is used as a marker for patients with serotonin-secreting neuroendocrine tumours (NET). Currently, the majority of laboratories measure 5-HIAA excretion in 24 h urine samples. Given the practicality and analytic problems of these samples, our laboratory successfully developed a LC–MS/MS method for the analysis of 5-HIAA in serum samples. Further to this, we have now developed a method to measure ...

Introduction: Methodological differences in the immunoassay measurement of cortisol are apparent when reviewing External Quality Assessment scheme data. A bimodal distribution is often observed, particularly for samples from female subjects. It has been postulated that some immunoassays are inefficient at removing cortisol from its binding proteins and therefore have the potential to under-recover from female samples. We investigated the results obtained from two immunoassays ...

Introduction: There has been much interest recently in measuring both salivary cortisol and cortisone due to the presence of 11β-hydroxysteroid dehydrogenase type 2 enzyme in the salivary glands. This enzyme facilitates the conversion of cortisol to cortisone; hence the concentration of cortisone in saliva may also be of interest. Studies have shown recently that salivary cortisone and cortisol are good markers of serum free cortisol status.Methods:...

The measurement of plasma renin activity is required in a number of clinical situations, in particular screening for primary aldosteronism (PA) and monitoring mineralocorticoid replacement therapy. PA is a treatable cause of hypertension and has an estimated prevalence of up to 20% amongst resistant hypertensives. Consequently, recent guidelines now recommend screening for PA in all patients groups with a high prevalence of PA. At present, the most reliable method of screening...

Introduction: It has been recognised in EQA schemes in Europe and America that the reproducibility between labs using LC–MS for testosterone analysis is not optimal for this technique. We decided to conduct a calibration exercise to investigate the variability seen between labs.Methods: Aqueous and matrix matched serum samples were sent to labs participating in the NEQAS testosterone scheme. The labs were asked to measure these samples blind using t...

Saliva contains the free unbound fraction of testosterone, which has been shown to correlate with the free circulating serum testosterone, and may better reflect the physiologically active form. Recently, measurement of free testosterone has gained international recommendations for the diagnosis of hypogonadism in the ageing male. Saliva collection is a non-invasive technique, offering more flexibility to the patient, e.g. the collection of samples at home. Liquid chromatograp...

For several years, steroid hormones including testosterone (T), androstenedione (A4) and 17-hydroxyprogesterone (17-OHP) have been utilised in the diagnosis of a range of conditions with clinical features of hyperandrogenaemia including polycystic ovary syndrome (PCOS) and congenital adrenal hyperplasia. In recent years a potential role for the 11-oxygenated androgens has emerged in the diagnosis and characterisation of androgenic disorders. Specifically, the 11-oxygenated and...

Measuring circulating androgen and gestagen concentrations is essential for the diagnosis and treatment monitoring of pathological conditions caused by abnormal steroidogenesis, such as congenital adrenal hyperplasia (CAH) and polycystic ovary syndrome (PCOS). Saliva collection represents a simple and non-invasive technique advantageous for multi sample profiling. We therefore developed a liquid chromatography-tandem mass spectrometry assay for the s...

Introduction: Current clinical practice guidelines recognise that a calculated free testosterone (T) level is the single most-useful, clinically sensitive marker of androgen excess in women, but there is no clear guidance as to the best way to measure free T. Several equations have been proposed to calculate clinically useful estimates of free T including the free androgen index (FAI) and calculated free T (cFT). The FAI is not used in men but it is...