[Daily clinical practice: Biological testing in osteoporosis].
Although biological testing has nothing to do with the diagnosis of osteoporosis, it can help the physician to: 1) identify secondary causes of low bone mass and/or fracture. There is however currently no consensus to define the biochemical parameters to be measured in this case. The cost-effectiveness of the biological evaluation, that is, measuring a minimum of parameters to detect a maximum of anomalies needs to be considered. Most experts agree that malignancy and especially a myeloma should be ruled out, and that an evaluation of calcium/phosphorus metabolism including the measurement of serum calcium, phosphate, PTH and 25 hydroxy-vitamin D should be performed. This allows to detect many anomalies including two very frequent conditions, primary hyperparathyroidism and vitamin D deficiency. Note however that complementary testing is generally needed to identify other diseases; 2) evaluate efficacy and observance of some osteoporosis treatments especially oral bisphosphonates. In this case, the evolution of the blood or urine level of some markers of bone turnover over a 3-6 month period after the initiation of therapy will be considered. For example, a decrease of more than 30% in the serum concentration of CTX (C-terminal telopeptide of type I collagen) will be regarded as a significant change indicating that treatment has reduced bone resorption.
Souberbielle
Jean-Claude
JC
Service d'Explorations Fonctionnelles du Pr. G. FRIEDLANDER Hôpital Necker-Enfants malades, Paris, France. jean-claude.souberbielle@nck.aphp.fr
Cormier
Catherine
C
D015519:Bone Density; D001859:Bone Neoplasms / Q000175:diagnosis; D002112:Calcifediol / Q000097:blood; D002118:Calcium / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology; D006801:Humans; D008297:Male; D009101:Multiple Myeloma / Q000175:diagnosis; D010024:Osteoporosis / Q000097:blood / Q000150:complications / Q000209:etiology / Q000503:physiopathology*; D010281:Parathyroid Hormone / Q000097:blood; D010710:Phosphates / Q000097:blood
D010281:Parathyroid Hormone; D010710:Phosphates; D002112:Calcifediol; D002118:Calcium