Important: This page provides general information only. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have concerns about your bone health, please speak to your doctor.
Understanding Your DXA Scan Results
Receiving your DXA scan results can be confusing — especially if you're not sure what the numbers mean. This page explains T-scores, Z-scores, and the categories of bone density in plain English.
The short version: find the T-score on your report. Above −1.0 is normal, −1.0 to −2.5 is osteopenia, and −2.5 or lower is osteoporosis. If more than one site was scanned, the lowest T-score is the one used to classify you. The raw density figure in g/cm² is not meaningful on its own and cannot be compared between different scanners.
What Is a T-score?
Your T-score is the key number in your DXA report. It compares your bone density to that of a healthy young adult (around age 30) of the same sex. It is expressed as a number of standard deviations above or below that reference point. A score of 0 means your bone density is exactly average for a healthy young adult; negative numbers indicate lower bone density.
| Category | T-score Range | What It Means |
|---|---|---|
| Normal | +1 to −1.0 | Bone density is within the normal range. Maintain bone health with good nutrition and exercise. |
| Osteopenia | −1.0 to −2.5 | Bone density is below normal but not classified as osteoporosis. Lifestyle measures and monitoring are recommended. |
| Osteoporosis | −2.5 or below | Bone density is significantly reduced. Treatment is usually recommended. Your doctor will advise. |
| Severe Osteoporosis | Below −2.5 + fracture | Osteoporosis with one or more fragility fractures. Prompt treatment and secondary prevention are essential. |
Example: A T-score of −1.8 at the hip would be classified as osteopenia. A T-score of −2.7 would be classified as osteoporosis.
What Is a Z-score?
Your report may also include a Z-score. Unlike the T-score, the Z-score compares your bone density to others of your own age and sex. A Z-score of 0 means you have the bone density expected for your age group.
A Z-score below −2.0 suggests your bone loss may be greater than expected for your age. This can prompt your doctor to investigate for secondary causes of bone loss — such as coeliac disease, thyroid problems, vitamin D deficiency, or medication side effects.
For most adults over 50, the T-score is used to diagnose osteoporosis and guide treatment. The Z-score is more relevant in younger adults.
If you have not been scanned yet, see how to get a DXA scan in Ireland for cost, medical card cover and where scanning is provided.
Bone Density by Age: What Is Expected
Bone is not a fixed quantity. You build it through childhood and adolescence, reach peak bone mass somewhere around 25 to 30, and then lose it slowly for the rest of your life. In women the loss steepens sharply for several years around menopause as oestrogen falls, which is why women reach the osteoporosis threshold earlier and more often than men.
Illustrative model based on IOF & IFLS-DB data. Women experience an accelerated decline around menopause.
This is why context matters when you read a report. A T-score of −1.6 in a woman of 75 is a common finding for her age; the same score in a woman of 45 is unusual and worth investigating. The T-score does not adjust for your age at all — that is exactly what the Z-score is for, and it is why your doctor looks at both.
| Life stage | What is happening to bone |
|---|---|
| Childhood to late teens | Rapid bone building. Around half of adult bone mass is laid down during adolescence. |
| Twenties | Peak bone mass is reached, typically between 25 and 30. This is the maximum you will ever have. |
| Thirties and forties | A slow, gradual decline begins in both sexes. Usually no symptoms and no clinical concern. |
| Menopause and the following 5–10 years | The steepest loss of a woman's life. Bone can be lost rapidly during this window. |
| Sixties onward | Loss continues more slowly in women and steadily in men. Fall risk begins to matter as much as density. |
The chart shows the general shape of bone density across life. It is illustrative of the pattern, not a diagnostic reference range — your own report is scored against the manufacturer's reference population.
What Does “Normal” Actually Mean?
A “normal” T-score does not mean there is nothing to be aware of. Bone density is only one piece of the picture. Your fracture risk also depends on your age, fall history, other medical conditions, and other factors. This is why the FRAX tool is often used alongside the DXA scan to give a more complete picture of your 10-year fracture risk.
What Should I Do After My Results?
If Your Result Is Normal
Continue to maintain good bone health through adequate calcium and Vitamin D, regular weight-bearing exercise, and a healthy lifestyle. Your doctor may recommend a repeat DXA scan in 2–5 years depending on your risk factors.
If Your Result Shows Osteopenia
- Discuss your lifestyle and diet with your doctor
- Ensure adequate calcium (from food, and supplementation if needed) and Vitamin D
- Increase weight-bearing and resistance exercise
- Address any modifiable risk factors (smoking, alcohol, low body weight)
- Ask about a repeat DXA scan — typically recommended every 1–2 years
- Your doctor may calculate your FRAX score to assess whether medication is appropriate
If Your Result Shows Osteoporosis
- Your doctor will discuss treatment options, which will likely include medication
- Ensure adequate calcium and Vitamin D intake (your doctor may recommend supplements)
- Review your falls risk and home safety
- Start or continue appropriate exercise
- Read our Treatment Options page for an overview of what may be offered
Important: Your results should always be interpreted by your doctor in the context of your full medical history. A number on a report only tells part of the story. Never change medication or start new supplements without speaking to your doctor or pharmacist first.
DXA Results: Common Questions
What is a normal bone density score?
A T-score between +1 and −1.0 is classed as normal. Between −1.0 and −2.5 is osteopenia, meaning bone density is below normal but not yet osteoporosis. A T-score of −2.5 or lower is osteoporosis. These cut-offs come from the World Health Organization and are used the same way in Ireland as elsewhere.
How do I read my DXA scan results?
Find the T-score first, and look at which site it refers to — usually the hip, the femoral neck or the lumbar spine. The lowest T-score across the measured sites is the one used to classify you. Ignore the raw density figure in grams per square centimetre; it means nothing on its own and cannot be compared between machines. If a Z-score is reported, that compares you with people your own age rather than with a young adult.
Is a T-score of −2.5 bad?
A T-score of −2.5 or lower meets the definition of osteoporosis and treatment is usually discussed at that point. It is not an emergency and it is not irreversible. What matters as much as the number is your overall fracture risk, which also takes in your age, any previous fracture, family history and medications — which is what the FRAX tool is for.
What is the difference between a T-score and a Z-score?
A T-score compares your bone density with a healthy adult at peak bone mass, around age 30. A Z-score compares it with other people of your own age and sex. T-score is what diagnoses osteoporosis. Z-score matters most in younger adults and children, where a low value suggests something other than normal ageing is causing bone loss and is worth investigating.
Does bone density naturally fall with age?
Yes. Bone mass peaks in the late twenties and declines slowly afterwards in everyone. In women the decline steepens sharply for several years around menopause as oestrogen falls, which is why women reach the osteoporosis threshold earlier and more often than men. A declining density is normal; the question is whether yours has fallen further than expected for your age.
How much change between two DXA scans is meaningful?
Less than you would think. Real biological change over a year is often smaller than the scanner's own margin of error, which is why scans are usually repeated no sooner than about two years apart and ideally on the same machine. Small differences between two reports are frequently measurement noise rather than real bone loss or gain.
Talk to Your Doctor
Always discuss your DXA results with your doctor. They will consider your full clinical picture — including your age, risk factors, and fracture history — to decide whether treatment or lifestyle changes are needed.
You can say: “I'd like to discuss my bone health and whether I should have a DXA scan.”
Questions to Ask Your DoctorLast reviewed: February 2026 — FragilityFracture.ie Editorial Team