Osteoporosis Tests & Diagnosis — What to Expect and What Your Results Mean
Osteoporosis is diagnosed by measuring bone mineral density — but diagnosing it accurately, understanding its underlying causes, and determining the most appropriate clinical response requires considerably more than a single scan. A DXA result tells you the density of the bone. It does not tell you why density is low, how fast it is changing, whether the internal architecture of the bone is compromised beyond what density alone indicates, or what the absolute fracture risk is when other clinical factors are taken into account.
At the London Osteoporosis Clinic, a bone health assessment integrates DXA scanning with fracture risk stratification, trabecular bone architecture analysis, lateral vertebral assessment where indicated, a comprehensive blood panel to identify underlying secondary causes, and a detailed clinical history. Together, these give a complete picture that supports both accurate diagnosis and a personalised clinical pathway.
The sections below explain each component of the assessment in plain clinical terms — what it measures, why it matters, and what the results mean.
The LOC Assessment Pathway
| Step | Assessment Component | What It Establishes |
|---|---|---|
| 1 | Clinical History | Risk factors, medication history, fracture history, family history, secondary cause identification. Frames everything that follows. |
| 2 | DXA Scan (Hip & Spine) | Bone mineral density at the two most clinically important fracture sites. Produces T-score and Z-score. Baseline for all future monitoring. |
| 3 | Trabecular Bone Score (TBS) | Bone microarchitecture quality — independent of density. Identifies structural compromise not visible in the T-score alone. |
| 4 | FRAX Fracture Risk Calculation | 10-year probability of major osteoporotic fracture and hip fracture specifically, incorporating clinical risk factors alongside DXA result. |
| 5 | Lateral Vertebral Assessment (LVA) | Identifies vertebral fractures that may be clinically silent (no pain, not previously diagnosed). Changes management in a significant proportion of patients. |
| 6 | Blood Panel | Secondary causes of bone loss: Vitamin D, PTH, calcium, renal and liver function, inflammatory markers, thyroid function, sex hormones where indicated. |
| 7 | Personalised Bone Health Plan | Synthesis of all findings into a written clinical plan: diagnosis, fracture risk category, treatment recommendation, monitoring schedule. |
DXA Scan — Dual-energy X-ray Absorptiometry
What it measures: Bone mineral density (BMD) at the lumbar spine (L1–L4) and proximal femur (hip). Results expressed as g/cm² and converted to standardised T-scores and Z-scores. Radiation exposure is extremely low — approximately 1/10th of a standard chest X-ray.
Clinical value: DXA is the internationally accepted gold-standard investigation for diagnosing osteoporosis and osteopenia, stratifying fracture risk, and monitoring treatment response over time. It is the single most important objective measurement in bone health assessment.
Further reading: Who needs a bone density scan? | Is a DEXA scan safe? | How DEXA scans support diagnosis and monitoring
Important: DXA measures density but not structural quality. Two patients can have identical T-scores with very different fracture risks depending on bone microarchitecture — which is why Trabecular Bone Score adds clinical value beyond DXA alone.
Understanding Your T-Score
| T-Score | WHO Classification | Relative Fracture Risk | Clinical Implication |
|---|---|---|---|
| 0 to −1.0 | Normal | Baseline | Lifestyle optimisation. Consider monitoring if risk factors present. |
| −1.0 to −2.5 | Osteopenia | 1.5–2× baseline | Increased risk. Consider treatment in presence of additional risk factors. Monitoring recommended. |
| Below −2.5 | Osteoporosis | 2–3×+ baseline | Clinical threshold for pharmacological treatment consideration. Full FRAX calculation and clinical assessment required. |
| Below −2.5 + fracture | Severe Osteoporosis | Highest risk category | Urgent treatment. Anabolic-first therapy strongly considered. Secondary fracture prevention priority. |
Understanding Your Z-Score
The Z-score compares your bone density to people of the same age and sex (rather than to the young adult reference population used for the T-score). A Z-score below −2.0 suggests that bone loss is greater than expected for age and should prompt investigation for secondary causes — underlying medical conditions, medications, or nutritional deficiencies that are accelerating bone loss beyond the expected age-related rate. This is one of the primary drivers for the blood panel component of the LOC assessment.
Additional Diagnostic Tests
Trabecular Bone Score (TBS)
What it measures: The microarchitectural texture of trabecular (spongy) bone in the lumbar spine, derived from the existing DXA scan image using software analysis. No additional scan or radiation exposure required.
Clinical value: TBS provides a measure of bone quality independent of bone density. Patients with identical T-scores can have very different fracture risks depending on their TBS. Particularly valuable in patients with diabetes or on glucocorticoid therapy, where T-score systematically underestimates fracture risk.
FRAX® Fracture Risk Assessment Tool
What it measures: The 10-year probability of a major osteoporotic fracture (spine, hip, wrist, or shoulder) and hip fracture specifically. Calculated using a combination of clinical risk factors with or without DXA result.
Clinical value: FRAX integrates DXA results with clinical risk factors — age, sex, BMI, prior fracture, family history, smoking, alcohol, glucocorticoid use, rheumatoid arthritis, and secondary osteoporosis — to produce an absolute fracture probability. This is the primary tool used to determine treatment thresholds under NOGG guidance.
Lateral Vertebral Assessment (LVA)
What it measures: A low-radiation lateral spine image acquired on the DXA table, identifying vertebral fractures — deformities, height loss, or wedging of individual vertebrae.
Clinical value: Vertebral fractures are frequently clinically silent: up to two-thirds occur without acute pain and are therefore undiagnosed. LVA identifies these pre-existing fractures — which are themselves the strongest predictor of future fracture risk — without requiring a separate X-ray.
Blood Tests — What Is Tested and Why
| Blood Marker | Normal Range* | What Abnormality Indicates | Clinical Implication |
|---|---|---|---|
| 25-hydroxyvitamin D | 50–125 nmol/L | Deficiency is the most common reversible secondary cause of bone loss | Supplementation dose guided by severity; recheck after 3–6 months |
| Calcium (adjusted) | 2.20–2.60 mmol/L | Hypercalcaemia may indicate hyperparathyroidism; hypocalcaemia may indicate malabsorption | PTH and further investigation if outside range |
| PTH (Parathyroid Hormone) | 1.6–7.2 pmol/L | Elevated PTH drives osteoclast activity and accelerates bone resorption | Primary hyperparathyroidism workup if elevated with hypercalcaemia |
| Bone-specific Alkaline Phosphatase (BSAP) | Laboratory-dependent | Elevated levels indicate high bone turnover — useful monitoring marker during treatment | High turnover may respond better to antiresorptive agents |
| Renal function (eGFR, creatinine) | eGFR >60 mL/min | Reduced renal function affects drug choice (bisphosphonates contraindicated with eGFR <35) | Guides safe pharmacological prescribing |
| Liver function (ALT, ALP, GGT) | Laboratory-dependent | Liver disease affects Vitamin D metabolism; ALP elevation may indicate bone disease | Rules out hepatic contribution to bone loss |
| Thyroid function (TSH, free T4) | TSH 0.4–4.0 mIU/L | Hyperthyroidism and over-treatment of hypothyroidism both accelerate bone resorption | Thyroid optimisation may independently improve bone density |
| Full blood count (FBC) | Standard ranges | Anaemia or haematological abnormalities may indicate inflammatory or malignant secondary cause | Excludes haematological disease as contributing factor |
| Inflammatory markers (CRP, ESR) | CRP <5 mg/L | Elevated markers suggest inflammatory secondary cause (RA, AS, PMR, IBD) | Guides investigation for inflammatory secondary osteoporosis |
| Sex hormones (FSH, LH, oestradiol; testosterone in men) | Age/sex-dependent | Early menopause, hypogonadism, or androgen deficiency all accelerate bone loss | Hormonal therapy considered as part of treatment plan |
*Reference ranges are indicative and laboratory-dependent. All results are interpreted by the consulting clinician in the context of the full clinical picture.
Related: Understanding Vitamin D and bone health | Secondary osteoporosis: when bone loss is a side effect | 8 conditions linked to osteoporosis
Urine Tests
Urine tests are used selectively, primarily to measure bone resorption markers — in particular urinary NTX (N-telopeptide) or CTX (C-terminal telopeptide), which reflect the rate at which bone is being broken down. These markers are useful for monitoring treatment response between DXA scans, as changes in resorption markers appear within weeks of starting treatment, whereas DXA changes take 12–24 months to become measurable. Urine calcium may also be measured to assess calcium balance and absorption.
What Happens After Your Assessment?
At the end of your initial assessment appointment, you will receive a written summary of your findings including your T-score and Z-score, your 10-year FRAX fracture probability, TBS result where applicable, a note of any significant blood test findings, a clear diagnosis or risk stratification, and a personalised bone health plan with specific recommendations.
| Result | Typical Next Steps |
|---|---|
| Normal bone density (T-score above −1.0) | Personalised lifestyle, nutrition, and exercise guidance to preserve bone health. Monitoring at 2–3 year intervals or sooner if new risk factors emerge. |
| Osteopenia (T-score −1.0 to −2.5) | Fracture risk stratification using FRAX. Lifestyle and nutritional intervention. Pharmacological treatment considered for high-risk subgroups. 12–18 month monitoring. |
| Osteoporosis (T-score below −2.5) | Full personalised treatment plan. Pharmacological therapy in most cases. Structured therapeutic exercise through the BoneRevive® Programme. 12-month DXA monitoring. Patients on the BoneRevive® Programme achieve an average 8–12% annual BMD improvement. |
| Severe Osteoporosis (T-score below −2.5 + fracture) | Urgent treatment initiation. Anabolic-first pharmacological strategy strongly considered. Maximum monitoring frequency. Secondary fracture prevention is the immediate clinical priority. |
| Secondary cause identified (e.g. Vitamin D deficiency, elevated PTH) | Treatment of underlying cause alongside bone-specific intervention. Recheck bloods after 3–6 months to confirm response. Bone density re-measured at 12–24 months. |
Frequently Asked Questions
How is osteoporosis diagnosed?
Osteoporosis is diagnosed primarily through DXA (Dual-energy X-ray Absorptiometry) scanning, which measures bone mineral density at the hip and spine and produces a T-score. A T-score at or below −2.5 meets the WHO diagnostic criteria for osteoporosis. A comprehensive assessment also includes a FRAX fracture risk calculation, blood tests to identify secondary causes, and clinical history review.
What is a T-score and what does it mean?
A T-score compares your bone density to the average peak bone density of a healthy young adult of the same sex. A T-score of 0 is exactly average. A score of −1.0 to −2.5 indicates osteopenia (below average density). A score at or below −2.5 indicates osteoporosis. Each unit decrease in T-score approximately doubles fracture risk at the hip.
What is a DXA scan and does it hurt?
A DXA scan is a low-radiation imaging technique that measures bone mineral density at the hip and spine. It is completely painless — you lie on a padded table while a scanning arm passes over your body. The radiation exposure is extremely low, approximately one-tenth of a standard chest X-ray. A DXA scan typically takes 10–15 minutes.
What is FRAX and how is fracture risk calculated?
FRAX is a validated clinical tool developed by the World Health Organisation that calculates your 10-year probability of a major osteoporotic fracture (spine, hip, wrist, or shoulder) and hip fracture specifically. It incorporates your DXA T-score alongside clinical risk factors including age, sex, BMI, prior fracture history, family history, smoking, alcohol intake, and whether you use corticosteroids or have certain medical conditions.
Do I need a GP referral for an osteoporosis assessment?
No. The London Osteoporosis Clinic operates on a self-referral basis — you can book a bone health assessment directly without a GP letter. Appointments are available at HCA Healthcare at The Shard in London and The Nuffield Hospital in Tunbridge Wells. Most private health insurance policies are accepted.
What blood tests are done as part of a bone health assessment?
A standard bone health blood panel typically includes Vitamin D, calcium, PTH (parathyroid hormone), bone turnover markers, renal and liver function, thyroid function, inflammatory markers, and sex hormones where clinically indicated. These tests identify secondary causes of bone loss — underlying conditions or deficiencies that may be driving bone loss beyond normal age-related change — and inform the most appropriate treatment strategy.
Related Reading
Understanding DEXA Scans
Fracture Risk & Secondary Causes
Ready to Understand Your Bone Health?
A consultant-led bone health assessment at the London Osteoporosis Clinic provides your DXA result, T-score, FRAX fracture probability, trabecular bone score, and a complete written clinical plan — all within a single appointment. No GP referral required. Results discussed with you on the day.
Book a Bone Health Assessment
+44 (0)20 7193 7867 | Mon–Fri, 9am–5pm | The Shard, London | Tunbridge Wells
