To identify whether osteoporosis is present, a test called the DXA scan (dual X-ray absorptiometry scan) is used to measure the thickness (or density) of the bone. Here an x-ray beam is directed at a small area of bone (usually the heel, spine, hip, or wrist). The thicker your bone is, the less x-ray beam will pass through it.

If you are being investigated for osteoporosis, you may have a blood sample taken to measure certain mineral and hormone levels, in addition to identification of risk factors in your personal history and physical examination. Blood calcium levels are usually normal in osteoporosis even if the bones are deficient, making this test useless for diagnosis. Alkaline phosphatase (ALP) is an enzyme that may be elevated in both liver and bone disease, but it is not normally increased in osteoporosis. Hormones produced by the brain (LH and FSH) and ovaries in women (oestradiol) or testicles in men (testosterone) may be measured to identify any deficiency. Protein levels may be examined in both blood and urine to identify the presence of multiple myeloma, a type of cancer associated with bone breakdown. Products of bone turnover can be found in blood and urine. These 'bone resorption' and 'bone formation' markers may be measured and are useful when monitoring a person's response to treatment with drugs which slow down bone breakdown.