Lumbar DEXA T-Score of -2.0: Osteopenia, Not Osteoporosis
A lumbar DEXA T-score of -2.0 indicates osteopenia (low bone mass), not osteoporosis, as the WHO diagnostic threshold for osteoporosis requires a T-score of -2.5 or lower. 1
WHO Diagnostic Classification
The World Health Organization defines bone mineral density categories based on T-scores as follows:
- Normal bone mass: T-score greater than -1.0 1
- Osteopenia (low bone mass): T-score between -1.0 and -2.4 1
- Osteoporosis: T-score equal to or less than -2.5 1, 2
Your T-score of -2.0 falls squarely in the osteopenia range, representing bone density that is 2 standard deviations below the mean of a healthy young adult reference population of the same gender. 1
Important Diagnostic Considerations
The diagnosis is based on the lowest T-score at any recommended skeletal site (lumbar spine, femoral neck, or total hip), not just the lumbar spine alone. 1 If you have DEXA measurements at other sites showing T-scores ≤ -2.5, the diagnosis would be osteoporosis regardless of the lumbar spine reading.
Once a diagnosis of osteoporosis is established (either by T-score ≤ -2.5 or by fragility fracture), it remains durable even if subsequent T-scores improve above -2.5. 1
Exceptions: When Osteopenia Becomes Osteoporosis
Even with a T-score of -2.0, you would be diagnosed with osteoporosis if any of the following apply:
- Vertebral fracture: Any vertebral compression fracture automatically establishes osteoporosis diagnosis regardless of T-score 3, 4, 5
- Hip fracture: A hip fracture in an older adult is diagnostic of osteoporosis without requiring BMD testing 5
- Other fragility fractures with osteopenia: Fractures of the proximal humerus, pelvis, or certain wrist fractures occurring with minimal trauma in the setting of osteopenia warrant an osteoporosis diagnosis 5
Risk Assessment and Treatment Decisions
For postmenopausal women and men over age 50 with osteopenia (T-score -1.0 to -2.4), treatment decisions should be guided by the FRAX fracture risk assessment tool. 1
The National Osteoporosis Foundation recommends pharmacologic treatment when FRAX calculations show:
- 10-year probability of hip fracture ≥ 3%, OR
- 10-year probability of major osteoporotic fracture ≥ 20% 1
FRAX incorporates multiple risk factors beyond BMD including age, gender, body mass index, prior fracture history, parental hip fracture, current smoking, glucocorticoid use, rheumatoid arthritis, secondary osteoporosis causes, and alcohol consumption. 1
Special Population Considerations
For premenopausal women and men under age 50, the WHO T-score classification system does not apply. 6 In these populations, Z-scores (comparison to age-matched controls) should be used instead, with a Z-score ≤ -2.0 indicating bone density "below expected range for age." 6
Common Pitfall to Avoid
Do not confuse osteopenia with osteoporosis in documentation or treatment planning. 6 These represent distinct diagnostic categories with different treatment thresholds and reimbursement implications. A T-score of -2.0 should be coded as M85.80 (other specified disorders of bone density and structure), not M81.0 (osteoporosis). 6