Osteoporosis can be diagnosed with the help of a blood test, but not definitively. Blood tests can show the level of blood calcium, and many people with osteoporosis can have a decrease in blood calcium, but a decrease in blood calcium is not always diagnostic of osteoporosis. Therefore, a blood test for calcium is useful in the diagnosis of osteoporosis, but it does not confirm the diagnosis. Bone density examination is the most reliable examination method for osteoporosis, which belongs to quantitative examination. Currently, the bone density examination method recognized by the international academic community is the measurement of dual-energy X-ray bone density, and its measured value can be used as the gold standard for the diagnosis of osteoporosis. The X-ray examination is qualitative and cannot be used for the diagnosis of early osteoporosis as it shows signs of bone loss of >30% to 50%.