Steroid hormone concentrations in dried blood spots: A comparison between capillary and venous blood samples.

Background: An important aspect of the shift towards dried blood spots (DBS) as a sample matrix for laboratory measurements, is the availability of robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods that can reliably quantify analyte concentrations in DBS. The development and validation of these LC-MS/MS methods, however, concerns an extensive process, for which large amounts of DBS samples are required. DBS are usually obtained from capillary blood samples, but they can also be prepared from venous (residual) blood samples, which are widely available in clinical laboratories.

The Value of Reducing Inconclusive and False-Positive Newborn Screening Results for Congenital Hypothyroidism, Congenital Adrenal Hyperplasia and Maple Syrup Urine Disease in The Netherlands.

Inconclusive and false-positive newborn screening (NBS) results can cause parental stress and increase healthcare expenditures. These results can be reduced by improving NBS algorithms. This was recently done for Congenital Hypothyroidism (CH), Congenital Adrenal Hyperplasia (CAH) and Maple Syrup Urine Disease (MSUD) in the Dutch NBS program.

Thyroglobulin and calcitonin measurements: pitfalls and future perspectives.

Thyroid cancer is the most prevalent endocrine cancer, and the prognosis depends on the type and stage of cancer at the time of discovery. The treatment involves (hemi-)thyroidectomy, possibly followed by additional therapeutic options. After treatment, patients are monitored using serum concentrations of endocrine tumour markers: thyroglobulin (Tg) in case of differentiated cancer and calcitonin in case of medullary thyroid cancer.

Neonatal reference intervals for serum steroid hormone concentrations measured by LC-MS/MS.

Objectives: Congenital adrenal hyperplasia (CAH) is a rare, inherited disorder of adrenal steroid synthesis. In many countries it is part of the neonatal screening program enabling early diagnosis and treatment. In case of an abnormal neonatal screening result or when other differences of sexual development (DSD) are suspected, measurement of serum steroid hormones using liquid chromatography coupled to mass spectrometry (LC-MS/MS) is needed for further diagnosis.

Confusion in the interpretation of prolactin levels caused by inappropriately low reference intervals.

Objective: Serum prolactin measurements are important in the differential diagnosis of pituitary masses and subfertility. We observed discrepancies in serum prolactin levels in several patients measured with different immunoassays. Despite differences in assay results, the reference intervals (RIs) derived by the manufacturers were similar.