The DXA (or sometimes called the DEXA) and pDXA (or sometimes called pDEXA) are both used to evaluate bone density. The DXA takes up to 10 minutes to complete and the pDXA takes less than 5 minutes. The DXA measures bone density in the lumbar spine, the hip (also called proximal femur), the forearm, or the total body. The pDXA testing is usually done on the forearm at the wrist or on the heel of the foot, but it can also be used higher on the forearm or on the fingers.
The pDXA machine is portable and can be used to screen bone density in large numbers of people, espe-cially in rural areas and at health fairs. The DXA machines are not mobile and are far more expensive than the pDXA machines. DXA testing is done with the patient lying down and pDXA can be done with the patient sitting up. The DXA uses a very small amount of radiation and the pDXA even less. The pDXA testing is only done for screening purposes. A diagnosis of osteoporosis can only be made using DXA.
So if your pDXA shows some bone loss, your clinician would likely recommend a DXA to evaluate your hip and spine. pDXA testing is not considered appropriate for monitoring bone density in patients undergoing treatments for osteoporosis because response to treatments is not as evident in the bones of your hands, arms, and feet.
pDXA testing on your forearm, usually your nondominant arm (for example, your left forearm if you are right handed), is not recommended if your forearm has been previously fractured, if it has a dialysis graft site, if it has been subject to prolonged immobilization, or if there is severe weakness or paralysis of that arm.