Endocrine Abstracts

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...

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...

Background: The low dose dexamethasone suppression test (LDDST) is an important investigation for suspected Cushing’s syndrome (CS). The traditional definition of normal suppression of serum cortisol to ≤50 nmol/l (0.5 mg 6 hrly × 48 hrs) comes from a time when biochemical auto analysers did not routinely detect very low values. Previous studies reported 5.1–8.3% of patients with Cushing’s disease (CD) suppressed to <50 nmol/l at 48 hrs. Many clin...