Executive summary of the position statement of the Spanish Societies SEQCML/SEEN/SEEP. Recommendations for the measurement of sex steroids in clinical practice.

Accurate measurement of sex steroids, particularly testosterone and estradiol, is relevant for the diagnosis and treatment of a wide range of conditions. Unfortunately, current chemiluminescent immunoassays have analytical limitations with important clinical consequences. This document reviews the current state of clinical assays for estradiol and testosterone measurements and their potential impact in different clinical situations. It also includes a series of recommendations and necessary steps to introduce steroid analysis by mass spectrometry into national health systems, a methodology recommended for more than a decade by international societies.

Macroprolactin: From laboratory to clinical practice.

Prolactin measurement is very common in standard clinical practice. It is indicated not only in the study of pituitary adenomas, but also when there are problems with fertility, decreased libido, or menstrual disorders, among other problems. Inadequate interpretation of prolactin levels without contextualizing the laboratory results with the clinical, pharmacological, and gynecological/urological history of patients leads to erroneous diagnoses and, thus, to poorly based studies and treatments. Macroprolactinemia, defined as hyperprolactinemia due to excess macroprolactin (an isoform of a greater molecular weight than prolactin but with less biological activity), is one of the main causes of such erroneous diagnoses, resulting in poor patient management when not recognized. There is no unanimous agreement as to when macroprolactin screening is required in patients with hyperprolactinemia. At some institutions, macroprolactin testing by polyethylene glycol (PEG) precipitation is routinely performed in all patients with hyperprolactinemia, while others use a clinically based approach. There is also no consensus on how to express the results of prolactin/macroprolactin levels after PEG, which in some cases may lead to an erroneous interpretation of the results. The objectives of this study were: 1. To establish the strategy for macroprolactin screening by serum precipitation with PEG in patients with hyperprolactinemia: universal screening versus a strategy guided by the alert generated by the clinician based on the absence or presence of clinical symptoms or by the laboratory when hyperprolactinemia is detected. 2. To create a consensus document that standardizes the reporting of prolactin results after precipitation with PEG to minimize errors in the interpretation of the results, in line with international standards.

Macroprolactin: From laboratory to clinical practice. / Macroprolactina: del laboratorio a la práctica clínica. Recomendaciones del grupo de trabajo de laboratorio de la SEEN y de la comisión de hormonas de la SEQCML sobre la medición e informe del resultado de la macroprolactina.

Prolactin measurement is very common in standard clinical practice. It is indicated not only in the study of pituitary adenomas, but also when there are problems with fertility, decreased libido, or menstrual disorders, among other problems. Inadequate interpretation of prolactin levels without contextualizing the laboratory results with the clinical, pharmacological, and gynecological/urological history of patients leads to erroneous diagnoses and, thus, to poorly based studies and treatments. Macroprolactinemia, defined as hyperprolactinemia due to excess macroprolactin (an isoform of a greater molecular weight than prolactin but with less biological activity), is one of the main causes of such erroneous diagnoses, resulting in poor patient management when not recognized. There is no unanimous agreement as to when macroprolactin screening is required in patients with hyperprolactinemia. At some institutions, macroprolactin testing by polyethylene glycol (PEG) precipitation is routinely performed in all patients with hyperprolactinemia, while others use a clinically based approach. There is also no consensus on how to express the results of prolactin/macroprolactin levels after PEG, which in some cases may lead to an erroneous interpretation of the results. The objectives of this study were: 1. To establish the strategy for macroprolactin screening by serum precipitation with PEG in patients with hyperprolactinemia: universal screening versus a strategy guided by the alert generated by the clinician based on the absence or presence of clinical symptoms or by the laboratory when hyperprolactinemia is detected. 2. To create a consensus document that standardizes the reporting of prolactin results after precipitation with PEG to minimize errors in the interpretation of the results, in line with international standards.

A Probabilistic Model for Cushing's Syndrome Screening in At-Risk Populations: A Prospective Multicenter Study.

CONTEXT: Cushing's syndrome (CS) is challenging to diagnose. Increased prevalence of CS in specific patient populations has been reported, but routine screening for CS remains questionable. To decrease the diagnostic delay and improve disease outcomes, simple new screening methods for CS in at-risk populations are needed. OBJECTIVE: To develop and validate a simple scoring system to predict CS based on clinical signs and an easy-to-use biochemical test. DESIGN: Observational, prospective, multicenter. SETTING: Referral hospital. PATIENTS: A cohort of 353 patients attending endocrinology units for outpatient visits. INTERVENTIONS: All patients were evaluated with late-night salivary cortisol (LNSC) and a low-dose dexamethasone suppression test for CS. MAIN OUTCOME MEASURES: Diagnosis or exclusion of CS. RESULTS: Twenty-six cases of CS were diagnosed in the cohort. A risk scoring system was developed by logistic regression analysis, and cutoff values were derived from a receiver operating characteristic curve. This risk score included clinical signs and symptoms (muscular atrophy, osteoporosis, and dorsocervical fat pad) and LNSC levels. The estimated area under the receiver operating characteristic curve was 0.93, with a sensitivity of 96.2% and specificity of 82.9%. CONCLUSIONS: We developed a risk score to predict CS in an at-risk population. This score may help to identify at-risk patients in non-endocrinological settings such as primary care, but external validation is warranted.

Thyroglobulin as early prognostic marker to predict remission at 18-24 months in differentiated thyroid carcinoma.

INTRODUCTION: Thyroglobulin (Tg), the most common marker to determine remission of differentiated thyroid carcinoma (DTC), can take 18 months or longer to be undetectable. We hypothesized that Tg stimulated after surgery and immediately before radioiodine treatment (baseline-stimulated Tg) could be a good predictor of remission at 18-24 months. The aim of this study was to evaluate the role of baseline-stimulated Tg as early prognostic marker of DTC. PATIENTS AND METHODS: Retrospective study of 133 patients with DTC from 1998 to 2010 (age at diagnosis 47·4 ± 16·8, follow-up 5·09 ± 3·2 years). Initial subset analysis was performed after excluding patients with positive TgAb, who were later included in the second. Baseline-stimulated Tg was divided into tertiles. Multivariate logistic regression analysis included baseline Tg and other known prognostic markers and receiver operating characteristic (ROC) curve to identify the best cut-off level of baseline Tg were performed. RESULTS: Baseline-stimulated Tg in the highest tertile was the only predictive variable of persistence of disease at 18-24 months in the initial analysis (OR 45·3, P < 0·01). In the second analysis, the predictive variables were baseline-stimulated Tg (OR 39·6, P < 0·001), presence of TgAb (OR 23·4, P < 0·005) and uptake outside of the thyroid bed post-treatment whole body scan (WBS; OR 5·3, P < 0·05) were predictive of persistence of disease. The ROC curve showed that baseline-stimulated Tg below 8·55 µg/l identified 95% of disease-free patients at 18-24 months after initial treatment. CONCLUSIONS: Baseline-stimulated Tg is a good predictor of remission of disease at 18-24 months after initial treatment and could be a useful marker to stratify risk immediately after surgery.