Skip to content

    Osteoporosis Health Center

    Font Size
    A
    A
    A

    Bone Scans and Bone Health Screenings

    When should you get a bone density scan, and why?

    Interpreting Your DEXA Bone Scan Results: T-Scores and Z-Scores

    DEXA scores are reported as "T-scores" and "Z-scores."

    • The T-score is a comparison of a person's bone density with that of a healthy 30-year-old of the same sex.
    • The Z-score is a comparison of a person's bone density with that of an average person of the same age and sex.

    Lower scores (more negative) mean lower bone density:

    • A T-score of -2.5 or lower qualifies as osteoporosis.
    • A T-score of -1.0 to -2.5 signifies osteopenia, meaning below-normal bone density without full osteoporosis.

    Multiplying the T-score by 10% gives a rough estimate of how much bone density has been lost.

    Z-scores are not used to formally diagnose osteoporosis. Low Z-scores can sometimes be a clue to look for a cause of osteoporosis.

    DEXA Bone Scans: What Your T-Score Means

    Being told your bones are thin is cause for concern, but not alarm. If your T-score is low, what can you expect?

    First of all, unless you're a woman past menopause or a man older than 50, your risk of fracture is very low. In these groups, even with a T-score less than -2.5, bones are usually strong and treatment isn't recommended.

    On the other hand, if you've been told you have osteoporosis, take it seriously. Feeling fine is no protection at all: fractures of the spine can be silent and painless. "Anyone with osteoporosis should be on some kind of treatment," according to Baker.

    For those with osteopenia (T-score between -1.0 and -2.5), the picture gets confusing. It's harder to predict fracture risk in this group of people. Focusing too closely on the T-score can be a mistake. "The DEXA T-score is not a perfect predictor for bone health or fracture risk," says Rhee.

    Actually, bone density (measured by T-score) is only one aspect of fracture risk. Your risk factors (see above) can be just as important. Using both the T-score and risk factors for fracture leads to better predictions.

    The World Health Organization is developing a formula using risk factors in combination with the T-score to determine 10-year fracture risk. "We'll probably see this coming into use in the next few years," says Rhee.

    Today on WebMD

    Women working out and walking with weights
    Reduce bone loss and build stronger muscles.
    Chinese cabbage
    Calcium-rich foods to add to your diet.
     
    woman stretching
    Get the facts on osteoporosis.
    Porous bone
    Causes, symptoms, risk factors, and treatment.
     
    senior woman
    Article
    Woman holding plate of brocolli
    Article
     
    wrist xray
    Quiz
    Superfood for Bones
    Slideshow
     
    mature woman
    Article
    sunlight in hands
    Article
     
    man and woman in front of xray
    Quiz
    woman with dumbbells
    Article