26th January 2024

DEXA scan 

The gold standard method of diagnosis for osteoporosis is a DEXA scan. Although DEXA carries an accuracy of more than 90% at the hip, it is important to note that false-positive results can be caused by conditions such as osteomalacia, osteoarthritis or soft-tissue calcification. A T-score of less than -2.5 on the DEXA indicates osteoporosis; a score of less than -2.5 with the presence of fragility fractures indicates severe osteoporosis. DEXA is the preferred method of diagnosis of osteoporosis; however, NICE guidelines states that for women aged 75 years or older who have one or more independent risk factors, DEXA may not be required if the clinician deems it to be clinically inappropriate or impractical to carry out. In addition, for some patients with vertebral fractures, it may be suitable to commence drug treatment without carrying out a DEXA scan. Other investigations, such as ultrasound measurement of bone at the heel or single-energy x-ray absorptiometry, can be used for the assessment of fracture risk; however, have not been validated for the diagnosis of osteoporosis. Plain x-rays can detect fractures and osteopenia (low bone density but not severe enough to cause osteoporosis) but not osteoporosis. CT scan can be used if DEXA is not available.