A guide to understanding the steroid pathway: new insights and diagnostic implications.

Steroid analysis has always been complicated requiring a clear understanding of both the clinical and analytical aspects in order to accurately interpret results. The literature relating to this specialised area spans many decades and the intricacies of the steroid pathway have evolved with time. A number of key changes, including discovery of the alternative androgen pathway, have occurred in the last decade, potentially changing our understanding and approach to investigating disorders of sexual development. Such investigation usually occurs in specialised paediatric centres and although preterm infants represent only a small percentage of the patient population, consideration of the persistence of the foetal adrenal zone is an additional important consideration when undertaking steroid hormone investigations. The recent expanded role of mass spectrometry and molecular diagnostic methods provides significant improvements for accurate steroid quantification and identification of enzyme deficiencies. However analysis of steroids and interpretation of results remain complicated. This review aims to provide an insight into the complexities of steroid measurement in children and offers an updated guide to interpretation, of serum and urine steroids through the presentation of a refined steroid pathway.