Endocrine Abstracts

Introduction: Most clinical laboratories use immunoassays to measure estradiol despite limitations such as poor specificity, poor sensitivity and wide variability between different manufacturers’ assays. LC–MS/MS assays overcome the issues of sensitivity and specificity however the methods reported in the literature often involve complex sample preparation and lengthy run times. We describe a simple, rapid assay for the simultaneous measurement of serum estradiol and...

Background: The C-3 epimer of 25 Hydroxyvitamin D3 (3-Epi-25OHD3) is produced in the liver by the epimerisation pathway of 25-hydroxy vitamin D3. It differs from 25OHD3 in configuration of the hydroxyl group at the third carbon (C-3) position. Despite the fact that little is known regarding its clinical significance, concerns have been raised that isobaric interference may result in over-estimation of total 25OHD when measured by liq...

Background: Plasma metanephrine analysis is widely accepted as the test of choice for phaeochromocytomas and sympathetic extra-adrenal paragangliomas. It is important to analyse 3-methoxytyramine along with metanephrine and normetanephrine as 3-MT measurement has been shown to be useful in tumour localisation and also in determining whether metastasis has taken place. 3-MT analysis is challenging as the concentrations of 3MT of interest are very low, and the sensitivity of man...

Iodine deficiency may lead to reduced thyroid hormone production and ultimately hypothyroidism. The UK has previously been considered to be iodine sufficient, however recent evidence suggests the UK may be iodine deficient. Iodine status can be assessed in several ways, including measurement of urinary iodine excretion, for which inductively coupled plasma-mass spectrometry (ICP-MS) is considered the gold standard method.An ICP-MS method for determinatio...

Preparations of recombinant insulin and insulin analogues are used in the treatment of insulin-dependent diabetes. Recombinant insulin that corresponds to the human sequence might be expected to cross-react extensively with insulin assays. Insulin analogues contain modifications that alter their action profiles and may therefore interact unpredictably with detection antibodies. In the differential diagnosis of hypoglycaemia it is important to be aware of the extent of the cros...

High performance liquid chromatography also called high pressure liquid chromatography (HPLC) is one of such sophisticated techniques by means of which we can do quantitative as well as qualitative measurement of different types of samples at a very low concentration even in the order of pictogram and nanogram level. The technology is an important one particularly in the field of Pharmaceutical Technology. Chromatography technique effects the separation of two or more componen...

Parathyroid hormone is involved in calcium homeostasis through interactions with vitamin D. Because intact and truncated forms of parathyroid hormone (PTH) vary in their biological activity, assays that can accurately quantify the ratio of intact hormone to its fragments are of increasing significance in the diagnosis of endocrine, renal and bone diseases. Vitamin D and its metabolites circulate tightly bound to vitamin D-binding protein (DBP). Because DBP concentrations are a...

Background: The development of recombinant biologics has had a major impact on many diseases. However, most biologics are rapidly cleared from the body and therefore require frequent injection regimens. There is therefore a need for technologies that allow the half-lives of these molecules to be extended in a predictable manner.HypothesisIncreasing numbers of N-linked glycosylation motifs between two GH molecules leads to gradually...

Background: We have previously demonstrated that the natriuretic peptides BNP and NT-proBNP rise with ascent to high altitude (HA). Both peptides are classically markers of congestive cardiac failure but have also recently been found to be associated with pulmonary hypertension at sea-level (SL). As pulmonary hypertension is central to the risk of high altitude pulmonary oedema we aimed to establish if there was any association between high pulmonary artery systolic pressure (...

The duty biochemist at Barts Health noted a testosterone result of 17 nmol/l on a 20-year-old female, measured by Roche E170 electrochemiluminescence immunoassay. Laboratory policy is that all female testosterone results >2.5 nmol/l by immunoassay (upper reference limit 1.92 nmol/l) are checked by LCMS to exclude analytical interferences. The LCMS result on this sample was below the limit of quantification (<0.5 nmol/l).Clinical details were &#14...

Introduction: A persistently elevated parathyroid hormone (PTH) following parathyroidectomy is usually associated with vitamin D deficiency. We have previously demonstrated this to occur in ~60% of post-operative patients. We have examined the effect of routine vitamin D replacement pre-operatively on the proportion of patients with persistently elevated PTH post-operatively.Methods: Data was collated retrospectively from our parathyroid database, includ...

Urine free cortisol (UFC) is analysed in 24 h urine collections in suspected Cushing’s syndrome, and provides an integrated measure of cortisol secretion over the whole day. The aim of this audit was to review how clinically useful UFC results were, and whether this analytical service was still justified. The current automated immunoassay with manual sample preparation was time-consuming, expensive (disproportionate quality control / external quality assessment (EQA) samp...

Hyponatremia is an electrolye disorder which is relatively common in hospitalised patients. Usually it is asymptomatic and mild but in severe cases has been associated with confusion and increased risk of morbidity and death. The aim of this study was to compare outcomes following fractured neck of femur (FNOF) in patients with and without hyponatremia and was facilitated by the population health datasets in Tayside obtained from the Health Informatics Centre, University of Du...

Introduction: Chromogranin-A (CgA) is a 49 kDa protein of the granin/secretogranin family originating from dense-core secretory granules within cells of the diffuse endocrine system. CgA is currently the best available diagnostic biomarker for neuroendocrine tumours (NETs) with recent clinical guidelines advocating the measurement of CgA as part of the baseline biochemical profile in patients presenting with symptoms suspicious of a gastroenteropancreatic NET.<p class="abs...

Long-term liquorice ingestion is a well-known cause of secondary hypertension and hypokalemia. However, its initial presentation with a very severe hypokalemia and rhabdomyolysis is exceedingly rare. We report a 46-year-old gentleman who presented with acute onset bilateral leg weakness. Medication included allopurinol, aminophylline, fluoxetine, gabapentin, omeprazole, and inhalers. He had a 40 pack year smoking history and drank alcohol heavily in the past.<p class="abst...

Introduction: There is controversy over which form of biochemical testing is best for screening for phaeochromocytoma/paraganglioma (PHAEO/PGL). Measurement of plasma metanephrines is the most sensitive test but is less specific and lacks widespread availability, and so many centres opt to measure 24-h urinary excretion of catecholamines and metanephrines. However, the standard 24-h urinary catecholamine profile also includes dopamine (DA), vanillylmandelic acid (VMA) and homo...

Liquorice (scientific name Glycyrrhiza glabra) is historically used for gastrointestinal complaints. Now it is primarily used as a flavoring agent in the tobacco, confectionery and to some extent in the pharmaceutical and beverage industries. Excessive intake of liquorice may cause a primary hyperaldosteronism-like syndrome characterized by sodium and water retention, hypertension, hypokalaemia, metabolic alkalosis, low-renin activity, and hypoaldosteronism. We descri...

Hypoparathyridsm and pseudohypoparathyroidsm are the common causes of pathological calcification in the brain though 0.3–1.5% cases are physiological. The clinical presentation of hypoparathyroidsm can vary with the calcium levels and chronicity of hypocalcaemia. We describe a 39-year-old female who had type one diabetes for the last 23 years. She was repeatedly hospitalised with collapse episodes thought to be hypoglycaemic though never proved. She also had primary hypop...

An association between the use of proton pump inhibitors (PPIs) and profound hypomagnesaemia has been highlighted in a number of case reports. As the prevalence of this occurrence or cause remain unknown, we undertook a review of patients with significant hypomagnesaemia in our hospital with a particular focus on use of PPIs and management.35 patients (21f; mean age (S.D.): 71.3 (14.6); median: 74 years) with significant hypomagnesaemia (d...

Background: Amongst hospitalised patients, hyponatraemia is the commonest electrolyte abnormality with reported prevalence of about 25%. Its association with mortality, morbidity and increased length of stay is well recognised, including adverse fracture risk and falls with mild hyponatraemia in elderly. We audited the management of hyponatraemia in inpatients in a University hospital setting.Methods: Over a 3-month period, amongst all in-patients, we id...

Introduction: Hyponatraemia, defined as serum sodium <135 mmol/l is one of the commonest electrolyte abnormalities seen in patients admitted to acute hospitals and is associated with increased morbidity and mortality. Impact of this condition is not adequately measured in critically ill patients admitted to intensive care unit. The aim of this observational study was to assess the incidence and outcomes of patients admitted to intensive care unit (ICU) in a UK based settin...

Introduction: Hyponatraemia is the commonest electrolyte disturbance occurring in 15–20% of inpatients (1), with significant clinical implications if mismanaged. We conducted a retrospective audit of our current management of hyponatraemia in our 1000 bedded trust.Method: Data of patients with severe hyponatraemia (Na<125 mmol/l) admitted to hospital over 4 weeks (Aug 2011) was collected. Twenty randomly selected cases were reviewed focusing on ...