Osteoporosis is a condition in which bones become progressively less dense and more fragile, increasing the risk of fracture — particularly of the hip, spine and wrist. It develops silently over years and is often only discovered after a fracture occurs.
Osteoporosis is far more common than most people realise — affecting an estimated 1 in 3 women and 1 in 5 men over the age of 50 globally. Fortunately, it is preventable, detectable and treatable. The key is knowing which tests to ask for and when.
Blood tests for bone health
Blood tests don't diagnose osteoporosis directly — bone density scanning does. But they are essential for identifying the underlying causes of bone loss and for monitoring treatment.
- Calcium — low calcium can drive parathyroid hormone to leach calcium from bone
- Vitamin D (25-OH vitamin D) — deficiency is a major, correctable risk factor for bone loss and fracture
- Parathyroid hormone (PTH) — elevated PTH causes bone resorption; primary hyperparathyroidism is a common cause of osteoporosis
- Full blood count — myeloma can cause osteoporosis and shows up as anaemia
- Thyroid function (TSH) — hyperthyroidism accelerates bone turnover
- Testosterone (men) — hypogonadism is a leading cause of osteoporosis in men
- Bone-specific alkaline phosphatase and CTX (C-terminal telopeptide) — bone turnover markers used to monitor treatment response
The DEXA scan: the gold-standard test
A DEXA (dual-energy X-ray absorptiometry) scan measures bone mineral density (BMD) at the hip and lumbar spine. The result is reported as a T-score — the number of standard deviations your density falls above or below the average for a young adult at peak bone mass. For a detailed walkthrough of what to expect from a DEXA appointment, our DEXA bone density scan guide covers the procedure end to end.
| T-score | Classification |
|---|---|
| Above −1.0 | Normal bone density |
| −1.0 to −2.5 | Osteopenia (low bone density) |
| −2.5 or below | Osteoporosis |
| −2.5 or below + fragility fracture | Severe osteoporosis |
Who should be screened?
- All women aged 65 and over
- Postmenopausal women under 65 with risk factors
- Men aged 70 and over
- Adults who have suffered a low-impact (fragility) fracture
- Anyone on long-term corticosteroids (prednisolone 7.5 mg/day or more for 3+ months)
- Adults with a condition associated with secondary osteoporosis: rheumatoid arthritis, coeliac disease, hyperparathyroidism, hypogonadism
Prevention and treatment
For prevention, the fundamentals are adequate calcium intake (1000–1200 mg/day from food where possible), vitamin D supplementation if deficient, weight-bearing exercise, not smoking and limiting alcohol. Our vitamin D test guide explains what your vitamin D number means, and our calcium blood test guide covers both high and low calcium in depth.
For established osteoporosis or high fracture risk, medication is usually added: bisphosphonates (alendronic acid, zoledronic acid) are the most commonly prescribed first-line agents. Anti-RANKL therapy (denosumab) and anabolic treatments (teriparatide, romosozumab) are used in severe or treatment-resistant cases.