Endocrine Abstracts

Plasma and urine 18-hydroxycortisol ('18-OHF') measurements are helpful to discriminate primary hyperaldosteronism (Conn's syndrome) caused by adrenal hyperplasia (normal 18-OHF) from adrenal adenoma or glucocorticoid suppressible hyperaldosteronism ( raised 18-OHF). We have developed DELFIA time-resolved fluorescence assays for 18-OHF as a second-line biochemical investigation for patients with raised plasma aldosterone/ renin ratios. Following ether extraction, test samples ...

Urine 18-hydroxy cortisol ('18OHF') measurements are claimed to have the potential to discriminate between primary hyperaldosteronism due to either Conn's syndrome/adrenal adenoma (increased values) or idiopathic adrenal hyperplasia (normal values), and also to identify cases of glucocorticoid-suppressible hyperaldosteronism ('GSH').We have evaluated three urine 18-OHF methods using a panel of samples from patients with primary hyperaldosteronism [due to either adenoma (N=...

Background: Familial dysalbuminaemic hyperthyroxinaemia (FDH) is an interesting autosomal dominant condition that is associated with euthyroid hyperthyroxinaemia, whereby patients remain euthyroid but laboratory value will show high free thyroxine (fT4) level. It is caused by mutations in ALB (albumin) gene that increase affinity of albumin for thyroxine (T4). The usual thyroid assay will show a spuriously high level of thyroxine. This interferen...

Introduction: Familial dysalbuminemic hyperthyroxinemia (FDH) is characterized by artefactual hyperthyroxinemia caused by enhanced binding affinity of thyroxine to the mutant albumin. However little is known about how FDH affects the measurement of thyroid hormones, especially FT3, across many assay platforms.Methods: Forty-eight genetically confirmed FDH patients (R218H mutation) had FT4 and FT3 measured with 1-step (ADVIA CENTAUR®, Siem...

Introduction: Physicians in our hospital notified the laboratory staff of a number of patients at the outpatient clinic with increased free T4 (fT4) concentrations without (complete) suppression of thyroid stimulating hormone (TSH). This phenomenon appeared to occur more frequently following implementation of a new automated fT4 immunoassay. The discordance between fT4 and TSH concentrations may be explained by analytical issues (not further explained here), incorrect referenc...

Metyrapone is a potent inhibitor of the conversion of 11-deoxycortisol (11-DOC) to cortisol and is used in the treatment of Cushing's syndrome. This study has assessed the clinical significance of 11-DOC cross-reaction in five serum cortisol assays provided on automated immunoassay analysers. Cross-reaction was determined from the linear regression of increase in measured cortisol against increasing levels of 11-DOC (0, 1590, 4310, 6490, 7040 nmol/L) added to a serum pool. In ...

Case history: 61 year old female with a history of inherited dilated cardiomyopathy was referred with abnormal thyroid functions not improving with Levothyroxine. She has been on Levothyroxine 100 mg which she has discontinued 5 months prior to the review but her thyroid function abnormality persisted. She had no family history of thyroid abnormalities.Investigations: Negative TSH receptor antibodies.Treatment and follow up:<table boarder="1" cellpad...

Heterophilic antibody interference in serum TSH immunoassays can result in misdiagnosis of patients with suspected thyroid disease. Rheumatoid factor (RhF) is an immunoglobulin with reactivity to the Fc portion of human IgG. Some RhF species also cross-react with animal immunoglobulins so have the potential to act as heterophile antibodies. As part of the Cambridge Supra-Regional Assay service for thyroid function testing five serum samples with strongly positive RhF and posit...

As thyroglobulin antibodies (TgAb) are a well recognised cause of interference in thyroglobulin (Tg) immunoassays current guidelines recommend that TgAb should be measured concurrently with Tg when monitoring thyroidectomised thyroid cancer patients. However the concordance between different TgAb assays has been questioned despite the availability of an International TgAb Reference Preparation (MRC 65/93).Four commonly used TgAb assays were tested in 145...

Aim: The aim of the study was the evaluation of the relationship between thyroid size and the result of radioactive iodine therapy in patients treated due to Graves’ hyperthyroidism.Material and methods: The study group included 150 subjects (127 M and 23 F), aged from 20 to 78 years (mean 48.33 years) at the moment of 131I therapy.In all patients the thyroid technetium-99m scan and determination of the serum levels...