BMD Measurement Information

Age Category Criteria
< 50 years Below expected range for age Z-score ≤ -2.0
Within expected range for age Z-score > -2.0
> 50 years Severe (established osteoporosis) T-score ≤ -2.5 with fragility fracture
Osteoporosis T-score ≤ -2.5
Low bone mass T-score -1.0 to -2.5
Normal T-score ≥ -1.0

T-score: number of standard deviations above (+) or below (-) the mean peak density;
Z-score: number of standard deviations above (+) or below (-) the mean density for an individual of that age and sex.

Fracture Risk: (10-year absolute): low (<10%) moderate (10% to 20%), or high (>20%).

Fracture risk predicted for an individual by this system applies only for a finite period of time, and that risk will change with advancing age or with the development of new clinical risk factors. Based on 2010 CAROC system. Papaioannou, A et al. 2010 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada: summary. CMAJ 2010;182:1864-73.

For the purpose of second and subsequent testing (MOHLTC Schedule of Benefits, 2010)

“high risk patient” means a patient:

1. at risk for accelerated bone loss (in the absence of other risk factors, patient age is deemed not to place a patient at high risk for accelerated bone loss); or

2. with osteopenia or osteoporosis on any previous BMD testing, or

3. with bone loss in excess of 1% per year as demonstrated by previous BMD testing.

High risk patient is limited to a maximum of one test every 12 months unless the ordering physician obtains written prior authorization from a medical consultant.

“low risk patient” means a patient who is not a high risk patient. Limited to a maximum of one second test not earlier than 36 months following baseline; subsequent test not earlier than 60 months following the second or any subsequent test.

Recommended Timing of Follow-Up BMD Tests

Expected Rate of BMD Change Clinical Example Timing of Follow-Up
Very High Moderate to high dose glucocorticoids, anabolic agent 6-12 months
High Osteoporosis drug therapy initiated or changed, low to moderate dose glucocorticoids 1-3 years
Moderate Therapy with nutritional supplements or lifestyle improvements 1-3 years
Low Stability documented on nutritional supplements or lifestyle improvements and with no change in clinical status; drug therapy shows to be effective 3-5 years
Very Low Normal results or low fracture risk, and no clinical risks 5-10 years

In some jurisdictions, the timing of follow-up may be restricted by provincial health insurance plans. In these circumstances, follow-up recommendations need to be applied in the context of local restrictions.

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Suggested Timelines for Reassessment of BMD and Fracture Risk.

Expected Rate of BMD Change Clinical Example Timing of Follow-Up
Very High Moderate to high dose glucocorticoids, anabolic agent 6-12 months
High Osteoporosis drug therapy initiated or changed, low to moderate dose glucocorticoids 1-3 years
Moderate Therapy with nutritional supplements or lifestyle improvements 1-3 years
Low Stability documented on nutritional supplements or lifestyle improvements and with no change in clinical status; drug therapy shows to be effective 3-5 years
Very Low Normal results or low fracture risk, and no clinical risks 5-10 years
Centres using FRAX2 Centres using CAROC*
If initiated pharmacotherapy: 3y If initiated pharmacotherapy 3y
If not a candidate for or chose not to take pharmacotherapy: If not a candidate for or chose not to take pharmacotherapy
If 10-y fracture risk <10% 5–10y If 10-y fracture risk <10% (low risk) 5–10y
If 10-y fracture risk 10%–15% 5y If 10-y fracture risk 10%–20% (moderate risk) 3–5y
If 10-y fracture risk >15% 3y If 10-y fracture risk >20% (high risk) 3y

*CAROC-based recommendations are a best fit of the FRAX-based recommendations.

CAR Practice Guideline on Bone Mineral Densitometry Reporting

Parameter Population Normative database Comments
T-score Postmenopausal women, Men aged 50 y or older White female NHANES III for femoral neck and total hip This T-score is used for both diagnostic category and fracture risk assessment
White female vendor database for other sites Though fracture risk is then established (FRAX, CAROC) using sex-specific fracture
Z-score Used clinically only in premenopausal women and men aged less than 50y Population specific vendor database for all sites Z-scores should be population specific where adequate reference data exist3
This should include sex-specific data
However, vendor BMD output typically includes the Z-score for all patients This should include sex-specific data
It may include ethnicity-specific, using the patient's self-reported ethnicity, if adequate reference data exists³

As per the CAR Practice Guideline on Bone Mineral Densitometry Reporting: 2024 Update, it is now recommended that the T-score used in establishing both the diagnostic category and the fracture risk is based on the female normative database.1,2

  1. Burrell S, et al. CAR Practice Guideline on Bone Mineral Densitometry Reporting: 2024 Update. Canadian Association of Radiologists Journal. 2025;76(3):417–426.

  2. The International Society for Clinical Densitometry. 2023 ISCD Official Positions Adult. 2023.