The definitive diagnosis of osteomalacia is made by bone biopsy using undecalcified sections and labelling with tetracycline. A fluorescent antibiotic, tetracycline localises at sites of mineralisation so that when sequential courses of tetracycline are given before bone biopsy, rates of bone mineralisation can be assessed. Other histological parameters that are quantified in a bone biopsy include the volume of osteoid tissue (that is, the volume of tissue that is non mineralised), the relative osteoid surface, and the osteoid seam thickness.
