Understanding DEXA Scans and T-Scores: What Your Bone Density Results Really Mean
Last Updated: June 9, 2026
The DEXA scan is the most widely used method for measuring bone density. While the scan itself is quick and painless, many people are left unsure how to interpret their results. This article helps breakdown what a DEXA scan measures and what exactly a T score and Z score is.
Bone density testing plays an important role in understanding fracture risk and long term bone health. Testing is most commonly recommended for women age 65 years or older and men age 70 years or older, though earlier screening may be appropriate for those who have experienced a fracture, have a family history of osteoporosis, or other risk factors.
What is a DEXA scan?
The most common type of bone density test is a DEXA scan, which stands for Dual Energy X ray Absorptiometry. It measures how much mineral, mainly calcium, is present in your bones, most often at the hip and spine. You will receive a separate T score for each area. The scan is simple and comfortable, and the radiation exposure is extremely low, far less than that of most medical imaging tests.
What is a T-Score?
The T score is the primary number reported on a DEXA scan. It compares your bone density in a specific area (typically hip or spine) to that of a healthy young adult, around age 30, when bone mass is at its peak.
In simple terms, the T score indicates how strong your bones are compared to peak bone density.
T-Score Interpretation
T Score Range: -1.0 or higher
Meaning: Normal bone density
T Score Range: Between -1.0 and -2.5
Meaning: Osteopenia (low bone density)
T Score Range: -2.5 or lower
Meaning: Osteoporosis
As you can see, a more negative T score indicates lower bone density and a higher risk of fracture. A higher score reflects stronger bones.
Diagnosis is not based on T score alone. Clinicians also consider age, fracture history, medications, and other health factors when evaluating bone health. Osteoporosis can be diagnosed based on a fragility fracture alone, even if your T-score is normal or shows only osteopenia. A fragility fracture is a broken bone that occurs from minimal trauma, such as a fall from standing height or less. Specific fractures that are diagnostic of osteoporosis include those of the spine, hip, wrist, humerus (upper arm), or pelvis.
This means that if you experience one of these fractures from low-level trauma, your healthcare provider may diagnose osteoporosis and recommend treatment regardless of your bone density test results. The presence of a fragility fracture indicates that your bones are vulnerable to breaking and require intervention.
T-Score vs. Z-Score: What is the Difference
You may also see a Z score on your bone density report. While the T score compares your bone density to a young adult reference group, the Z score compares your results to people of the same age, sex, and body size.
T scores are primarily used to diagnose osteopenia and osteoporosis in adults.
Z scores are more commonly used in younger individuals or when clinicians are evaluating unexpected bone loss.
Both scores provide helpful context, but the T score is the main driver of clinical decision making in most adults.
Other Types of Bone Density Testing
While DEXA is considered the gold standard, other methods may be used in specific situations.
Quantitative Computed Tomography (qCT)
This test uses CT imaging to assess bone density in three dimensions. It can provide more detailed information but involves higher radiation exposure and is not commonly used for routine screening.
REMS (Radiofrequency Echographic Multi-Spectrometry)
Some newer technologies estimate bone density using sound waves and do not involve radiation. While promising, these methods are still emerging and are not widely accepted as replacements for DEXA scans clinically.
Bone Turnover Markers
Blood or urine tests can measure how quickly bone is being broken down or formed. These tests do not measure bone density directly but can help monitor changes in bone metabolism or response to treatment.
Why Bone Density Testing Matters
Bone loss often occurs without noticeable symptoms until a fracture happens. Bone density testing allows clinicians to identify risk early, when preventive strategies and targeted interventions can be most effective.
Testing is commonly recommended for:
Women age 65 years or older
Men age 70 years or older
Adults with risk factors such as family history, low body weight, or long term use of certain medications
Anyone who experiences a fracture after age 50
Bone density results are often combined with clinical history and fracture risk calculators to guide next steps.
Frequently Asked Questions
How often should I have a DEXA scan?
Most people are tested every one to two years, depending on age, risk factors, and whether they are undergoing treatment. Your healthcare provider can recommend the appropriate interval.
Can my T score improve over time?
Yes. Bone density changes slowly, but progressive strength training, appropriate impact exercise, and adequate nutrition can help maintain or improve bone density over time. Your healthcare provider can recommend appropriate medications and treatment options best for you.
Does a normal T score mean my fracture risk is zero?
No. Bone density is only one factor in fracture risk. Muscle strength, balance, fall risk, and overall health also play important roles.
Is the radiation from a DEXA scan safe?
The radiation exposure from a DEXA scan is extremely low and is considered safe, even with repeat testing.
If I have osteopenia, does that mean I will develop osteoporosis?
Not necessarily. Many people with osteopenia are able to maintain or improve bone health with appropriate movement, nutrition, and monitoring.
Key Takeaways
A DEXA scan is a simple and reliable way to measure bone density
The T score compares your bone strength to peak bone density
Lower T scores indicate weaker bones and higher fracture risk
Bone density is an important part of bone health, but it is not the whole picture
Understanding your results is the first step toward taking an active role in protecting your long term bone health.
References
Bone Health and Osteoporosis Foundation — patient and clinician resources on bone density testing
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) — Osteoporosis Overview
Centers for Disease Control and Prevention — Osteoporosis and Low Bone Mass in Older Adults
Mayo Clinic — Bone Density Test Overview
ARUP Consult — Osteoporosis Diagnostic Resource