Diagnosis of Osteoporosis
Which tests are used to evaluate osteoporosis will depend on your age, symptoms, and current health. In determining a patient’s risk from bone loss, a doctor is likely to use BMD test and FRAX calculator
The USPSTF recommends using FRAX to calculate risk with subsequent testing of the following groups:
- All women 65 and older
- Women 50-64 with 10-year risk of fracture of 9.3% or more
FRAX Fracture Risk Assessment Tool
- Is a fracture risk assessment tool that allows for calculation of future risk of fracture based on patient characteristics
- Calculates the 10-year risk for osteoporotic fractures
- FRAX is a free online tool, invented by the World Health Organization, that accurately predicts a patient’s risk of fracture. Because osteoporosis is so common among people over fifty, FRAX is particularly useful to primary care physicians who can use it with or without a bone density test. Patients can use this tool themselves though they will need to convert height and weight to centimeters to get accurate results. The FRAX is available at no cost through the University of Sheffield at this address: https://www.shef.ac.uk/FRAX/tool.jsp
Imaging
The most common test for osteoporosis is a non-invasive x-ray of bones. This procedure, known as a bone mineral density (BMD) test, commonly targets the bones most at risk for problematic breaks: wrist, spine, and hip. In all cases, the BMD compares the patient’s bones to the bones of a healthy young adult. Where the patient’s bones are less dense than those of a healthy young adult, the precise measure of density determines which category of bone loss is diagnosed. When examining the results of a bone density scan, a doctor makes a judgment as to whether the patient is likely to break a bone within the next ten years because of bone loss. This judgment largely determines the type of treatment that is prescribed.
- Bone densitometry by dual energy x-ray absorptiometry of the hip and posteroanterior lumbar spine (wrist may be used in obese) is the most commonly used bone measurement test
- Used for definitive diagnosis of osteoporosis
- Densitometric osteopenia (T-score <-1.0 and > -2.5)
- Densitometric osteoporosis (T-score < -2.5)
- Quantitative ultrasonography is less expensive and more portable than DXA and does not expose patients to ionizing radiation
- CT scan
- MRI
- Plain radiographic films should only be used to detect fracture. Not be used for evaluation because do not detect bone mass loss until 40-50%
Labs
Routine chemistry profiles are usually normal in idiopathic osteoporosis, but should be tested to rule out underlying processes.
- CBC and diff, electrolytes, vitamin D, fasting calcium and phosphorous, serum glucose, BUN, creatinine
- TSH level in should be checked in those receiving thyroid hormone to identify secondary causes
- Specialists will looks at bone resorption markers (N-telopeptides and C-telopeptides) used to evaluate osteoclast activity and bone formation markers (bone-specific alkaline phosphate, osteocalcin, procollagen I extension peptides) to evaluate osteoblast activity, high levels imply increased bone turnover.
Invasive Testing
Bone biopsy, done by specialist if indicated to rule out cancer and other medical conditions.