Table 4.

Laboratory testing in serum or urine for searching of secondary causes in children and young adults

Basic laboratory testing  Blood cell count  Calcium, albumin, phosphate, ALP (total and bone specific)  25-OH Vitamin D, PTH  Creatinine  ESR  TSH, fT4, fT3  24 h urine calcium and creatinine (in children spot urine)

Additional laboratory testing  Bone turnover markers (e.g. PINP, CTX)  Fasting glucose, HbA1c  IGF1  Iron, ferritin, AST, ALT, tTG-IgA antibodies, anti-DGP- IgG antibodies  LH, FSH, E2  LH, FSH, testosterone, SHBG  Morning cortisol, ACTH, midnight cortisol, UFC, DST  Prolactin  Protein immunoelectrophoresis in serum/urine  Tryptase

ACTH adrenocorticotropic hormone, ALP alkaline phosphatase, ALT alanine transaminase, AST aspartate transaminase, CTX C-terminal telopeptide, DGP deamidated gliadin peptide, DST dexamethasone suppression test, E2 oestradiol, ESR erythrocyte sedimentation rate, FSH follicle-stimulating hormone, fT3 free T3, fT4 free T4, HbA1c glycosylated haemoglobin, 25-OH Vitamin D 25-hydroxy vitamin D, IGF1 insulin-like growth factor 1, LH luteinising hormone, PINP procollagen type I N-terminal propeptide, PTH parathyroid hormone, SHBG sex hormone-binding globulin, TSH thyroid-stimulating hormone, tTG tissue transglutaminase, UFC 24 h urinary free cortisol