PTH immunoassay interference: differential diagnosis with normocalcemic primary hyperparathyroidism?

The main diagnostic dilemma in normocalcemic hyperparathyroidism is differentiating this condition from secondary hyperparathyroidism and other causes of elevated parathyroid hormone (PTH) levels in eucalcemic patients, including potential assay interferences. Despite the analytical sensitivity of immunoassays, they may lack adequate accuracy due to several analytical interferences, such as the presence of heterophilic antibodies. Immunoassays for PTH measurement use the immunometric "sandwich" technique, and only a few cases of interference with this assay have been reported to date.

Alert for the high prevalence of vitamin D deficiency in adolescents in a large Brazilian sample.

Objective: To estimate the prevalence of vitamin D deficiency and severe deficiency in children and adolescents, in a large Brazilian sample.

Methodology: Results of 413,988 25(OH)D measurements in children and adolescents aged 0 to 18 years collected between 01/2014 and 10/2018 were obtained from the database of a Clinical Laboratory. In this population, 25 hydroxyvitamin D concentrations below 20 ng/mL are considered deficient, and below 12 ng/mL as severe deficiency.

False diagnosis of recurrent thyroid carcinoma: the importance of testing for heterophile antibodies.

Thyroglobulin (Tg) levels are important to predict recurrence in differentiated thyroid cancer patients.However, false-positive results can hence the request of unnecessary tests and treatments. We reported two cases of interference in thyroglobulin measurement and the workup to investigate them.

Levels of bioavailable, and free forms of 25(OH)D after supplementation with vitamin D in primary hyperparathyroidism.

The 25 hydroxyvitamin D [25(OH)D] is the major metabolite for ascertaining vitamin D status, which circulates bound to a specific carrier (vitamin D-binding protein - VDBP). A portion that circulates unbound vary according to the VDBP genotype. This study evaluates the behavior of different forms of 25(OH)D, before and after supplementation with 14,000 IU of vitamin D3, weekly for 12 weeks, in individuals with primary hyperparathyroidism and controls.

Trabecular Bone Score (TBS) in Primary Hyperparathyroidism (PHPT): A Useful Tool?

Primary Hyperparathyroidism (PHPT) often leads to bone loss, even in its asymptomatic presentations. Trabecular Bone Score (TBS) is a method to assess the trabecular bone structure of the spine. This study aimed to evaluate TBS measurements combined with Dual X-ray Absorptiometry (DXA) values in the search for more accurate bone fragility risk assessment among PHPT patients.

Global FT4 immunoassay standardization: an expert opinion review.

Objectives: Results can vary between different free thyroxine (FT4) assays; global standardization would improve comparability of results between laboratories, allowing development of common clinical decision limits in evidence-based guidelines.

Content: We summarize the path to standardization of FT4 assays, and challenges associated with FT4 testing in special populations, including the need for collaborative efforts toward establishing population-specific reference intervals. The International Federation of Clinical Chemistry and Laboratory Medicine Committee for Standardization of Thyroid Function Tests has undertaken FT4 immunoassay method comparison and recalibration studies and developed a reference measurement procedure that is currently being validated.

Prediction of bone mass changes after successful parathyroidectomy using biochemical markers of bone metabolism in primary hyperparathyroidism: is it clinically useful?

Objective: To measure type 1 serum amino-terminal propeptide procollagen (P1NP) and type 1 cross-linked C-terminal telopeptide collagen (CTX) before parathyroidectomy (PTX) in PHPT patients, correlating these measurements with bone mineral density (BMD) changes.

Subjects And Methods: 31 primary hyperparathyroidism (HPTP) were followed from diagnosis up to 12-18 months after surgery. Serum levels of calcium, parathyroid hormone (PTH) vitamin D, CTX, P1NP, and BMD were measured before and 1 year after surgery.

Experience with a third-generation parathyroid hormone assay (BIO-PTH) in the diagnosis of primary hyperparathyroidism in a Brazilian population.

Objective: To evaluate the usefulness of a third-generation PTH assay in the diagnosis of primary hyperparathyroidism (PHPT).

Subjects And Methods: Forty-one PHPT patients (4 men and 37 women) with 61.2 ± 10.

Parathyroid responsiveness during hypocalcemia after total parathyroidectomy and autotransplantation in patients with renal hyperparathyroidism.

Introduction: Hyperparathyroidism is a frequent complication of chronic kidney disease (CKD). Total parathyroidectomy (PTX) with parathyroid tissue autotransplantation (AT) is a treatment option in those individuals that do not respond to clinical management.

Objective: To evaluate grafted parathyroid tissue response during induced hypocalcemia among CKD patients who underwent total PTX with AT.

Determination of cortisol and cortisone in human saliva by a liquid chromatography-tandem mass spectrometry method.

Objective: Salivary cortisol measurement plays an important role in the evaluation of adrenal function. Its high correlation with free serum cortisol, the easy of sampling and the limited presence of interfering steroids, generated multiple recent studies of its application, in special in the screening of adrenal hyperfunction. In this paper we present our experience in the development of a high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for salivary cortisol and cortisone measurement.

Autotransplant tissue selection criteria with or without stereomicroscopy in parathyroidectomy for treatment of renal hyperparathyroidism.

Introduction: Several methods have been proposed to improve operative success in renal hyperparathyroidism.

Objective: To evaluate stereomicroscopy in parathyroid tissue selection for total parathyroidectomy with autotransplantation in secondary (SHPT)/tertiary (THPT) hyperparathyroidism.

Methods: 118 renal patients underwent surgery from April of 2000 to October 2009.

Intraoperative PTH cutoff definition to predict successful parathyroidectomy in secondary and tertiary hyperparathyroidism.

Unlabelled: In order to improve success rates in surgery of renal hyperparathyroidism, we evaluated intraoperative PTH (IOPTH) measurement utility.

Method: 86 patients underwent total parathyroidectomy with intramuscular presternal autotransplantation from 04/2000 to 10/2009 and were followed for 26.5 months on average (prospective cohort).

Parathyroid carcinoma and hungry bone syndrome.

We hereby report two patients with parathyroid carcinoma presenting extremely high calcium and PTH levels, severe bone disease, and palpable neck mass at diagnosis. They both underwent parathyroidectomy, and one of them evolved to lung metastasis. Important hypocalcemia was observed after surgery in both: after parathyroidectomy in one patient, and only after surgical removal of the metastasis in the other.

Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy.

Objective: The purpose of this study was to evaluate if the measurement of peri-operative parathyroid hormone (PTH) is able to identify patients with increased risk of developing symptoms of hypocalcemia.

Subjects And Methods: Forty patients who underwent total thyroidectomy were studied prospectively. Ionized serum calcium and PTH were measured after induction of anesthesia, one hour (PTH1) and one day after surgery (PTH24).

Effects of ghrelin, GH-releasing peptide-6 (GHRP-6) and GHRH on GH, ACTH and cortisol release in hyperthyroidism before and after treatment.

In thyrotoxicosis GH responses to stimuli are diminished and the hypothalamic-pituitary-adrenal axis is hyperactive. There are no data on ghrelin or GHRP-6-induced GH, ACTH and cortisol release in treated hyperthyroidism. We, therefore, evaluated these responses in 10 thyrotoxic patients before treatment and in 7 of them after treatment.

Effects of ghrelin, growth hormone-releasing peptide-6, and growth hormone-releasing hormone on growth hormone, adrenocorticotropic hormone, and cortisol release in type 1 diabetes mellitus.

In type 1 diabetes mellitus (T1DM), growth hormone (GH) responses to provocative stimuli are normal or exaggerated, whereas the hypothalamic-pituitary-adrenal axis has been less studied. Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6). Ghrelin's effects in patients with T1DM have not been evaluated.

[Search of prostatic tissue in 46,XX congenital adrenal hyperplasia].

Objectives: To describe the presence of prostatic tissue in 46,XX patients with the classical form of congenital adrenal hyperplasia (CAH); to evaluate the sensitivity and specificity of prostatic specific antigen (PSA) measured in congenital adrenal hyperplasia patients with regard to the detection of prostatic tissue in pelvic MRI.

Methods: We studied 52 children and adolescents, 32 with the classical form of congenital adrenal hyperplasia, 10 boys and 10 girls without CAH. Pelvic MRI was performed in all patients to detect prostatic tissue.

The effect of identifying macroprolactinemia on health-care utilization and costs in patients with elevated serum prolactin levels.

Objectives: The routine screening for macroprolactin of all hyperprolactinemic patients may avoid unnecessary imaging procedures and medication prescription. The study described the frequency and types of tests requested after a diagnosis of high serum prolactin concentration, and assessed whether the diagnosis of macroprolactinemia resulted in lower downstream utilization and costs compared with hyperprolactinemic patients.

Methods: A cost analysis was conducted using a decision tree to model the health-care utilization of the two groups.

Simultaneous quantitation of seven endogenous C-21 adrenal steroids by liquid chromatography tandem mass spectrometry in human serum.

Quantitation of endogenous steroids is important in the diagnosis of several endocrine disorders. In this study we present a new method for simultaneous quantitation of cortisol, cortisone, 11-desoxycortisol, 21-desoxycortisol, corticosterone, 17-hydroxyprogesterone and 11-desoxycorticosterone in human serum by on-line extraction and LC-MS/MS. Analytes extraction was performed on-line using a 2-position and 6-port valve equipped with a monolithic silica cartridge.

Glucocorticoid sensitivity in young healthy individuals: in vitro and in vivo studies.

Context: Interindividual variation and tissue specificity of glucocorticoid (GC) sensitivity may occur in healthy subjects.

Objective And Participants: The objective of this study was to evaluate the GC sensitivity in 40 healthy young subjects (21 women and 19 men; 22-42 yr old).

Design: We measured salivary and plasma cortisol levels before and after the administration of 0.

The role of insulin-like growth factor I, growth hormone, and plasma proteins in surgical outcome of children with congenital heart disease.

OBJECTIVE: To evaluate postoperative serum concentrations of growth hormone (GH), insulin-like growth factor I (IGF-I), C-reactive protein (CRP), and prealbumin as predictors of clinical outcome as defined by the incidence of 30-day postoperative mortality, the postoperative length of pediatric intensive care unit (PICU) stay, and the risk of postoperative infection in infants of high surgical risk undergoing operative correction of congenital cardiac defects. DESIGN: Prospective, observational study. SETTING: PICU of a university hospital.