Osteoporosis is a condition that causes progressive bone loss. As bones weaken, the likelihood of fractures can increase. Osteoporosis screening often helps in detecting the disease in time. A bone density test, usually conducted at two-year intervals, is commonly used for screening and diagnosis of osteoporosis. The results of a bone density test can indicate disease onset, risk of suffering a fracture, and could assist in assessing efficacy of osteoporosis treatment.
Generally, osteoporosis screening is recommended to individuals more likely to develop the disease. These include women over 65 and men over 70. Postmenopausal women who are below 65 but have a family history of osteoporosis and women who have experienced an early menopause may be screened. Osteoporosis screening could be suggested for those on medications such as prednisone, or have a condition such as type one diabetes or hyperthyroidism that can raise their risk of the disease.
Osteoporosis might not cause symptoms initially, but sometimes as the disease sets in a person can shrink in height and develop a slight hump on the upper back. Some could suffer a type of fracture that is frequently attributed to osteoporosis. In such instances a doctor might ask for a test to diagnose osteoporosis.
A test that detects changes in bone density is frequently used for osteoporosis screening. A bone density test typically determines the amount of calcium and other minerals present in a bone. The mineral content indicates density of the bone and in turn its strength. Low mineral content could increase chances of fracturing a bone. In people who have osteoporosis and are undergoing treatment, the test may be performed after two years to check the effect of therapy.
There are different techniques of measuring bone density. The test may be conducted at a doctor’s office or at a hospital’s radiology department. Some devices test bone density in peripheral areas that include the finger, heel, and wrist. A test of the peripheral parts may help determine if a person is at risk for suffering a fracture in the short term. Some procedures involve bigger devices that test bone density of the hip and spine areas which are generally regarded as better indicators of osteoporosis.
A dual-energy X-ray absorptiometry (DEXA) that checks bone density of the spine, hip or the entire body is one of the standard tests used. It is a painless procedure that typically involves nominal radiation exposure. The test can usually be done in about 10 to 15 minutes. This test is used most often in osteoporosis screening as it offers more reliable results. Usually it takes about two to three days to receive the test results.
Quantitative computed tomography can be performed to measure the density at the spine and for 3-D images of a person’s bones. The test could be more expensive and might expose one to more radiation than DEXA. Sometimes radiographic absorptiometry, a method that determines bone density from a hand X-ray can be conducted. A technique called quantitative ultrasound could be used to measure bone density at the heel or kneecaps with the help of sound waves. Some medical plans may cover the cost of a bone density test if the individual has osteoporosis risk factors and a doctor recommends the procedure.
Generally, bone density test results include T-scores and Z-scores. The T-score component often compares an individual’s bone density with the values of healthy individuals of the same gender. While a positive score suggests that the person tested has bones that are stronger than average for that group, a negative T-score signifies low bone density. According to World Health organization norms, a T-score in the -1 to -2.5 range could be an indicator of osteopenia, a condition where bone loss has just begun. A T-score in the -2.5 or lower range might indicate that a person has osteoporosis.
The Z-score usually compares values of individuals of similar age, gender, and race. It could help detect osteoporosis that might not be age-related, but due to some other condition. A doctor might suggest laboratory tests to ascertain the reason for the low bone density. Treating the underlying condition could be necessary to stop bone loss.