Challenges in the diagnosis and follow-up of Cushing's syndrome: Evaluating LC-MS/MS as a confirmation method for urinary free cortisol analyses.

24-h urinary free cortisol (UFC) measurements are fundamental in the diagnosis and follow-up of Cushinǵs syndrome (CS) and immunoassays (IA) are the most widely used tests for its quantification in clinical laboratory practice. However, their suitability has been questioned mainly due to their limitations concerning analytical specificity. The aim of this research project was to evaluate a novel algorithm for CS diagnosis and follow-up in the clinical laboratory, based on the combination of IA tests with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for UFC quantification.

Interference by vitamin B12-macrocomplexes: towards an effective detection and correct interpretation of hypo- and hypervitaminemia.

Objectives: The presence of macro-B12 is a cause of factual hypervitaminemia B12. Precipitation with polyethylene glycol (PEG) is a simple method of removing high-molecular-weight biomolecules. However, "free" molecule may co-precipitate.

Spitz tumours and mimickers.

Since their initial description in 1948, Spitz tumours have always been a challenge in the field of dermatopathology and paediatric pathology. Advances in molecular pathology have confirmed they are associated with specific anomalies, mainly gene fusions. They display a wide range of clinical presentations and histological subtypes.