What are normal z-scores for bone density?
What are normal z-scores for bone density?
Bone density Z-score chart
| Z-score | Meaning |
|---|---|
| 0 | Bone density is the same as in others of the same age, sex, and body size. |
| -1 | Bone density is lower than in others of the same age, sex, and body size. |
| -2 | Doctors consider scores higher than this to be normal. |
| -2.5 | This score or lower indicates secondary osteoporosis. |
What does Z-score mean on a bone density scan?
A Z-score compares your bone density to the average values for a person of your same age and gender. A low Z-score (below -2.0) is a warning sign that you have less bone mass (and/or may be losing bone more rapidly) than expected for someone your age.
What is the standard deviation for bone age?
The standard deviation of bone age at a given age is approx 1 year.
What are the T-score and Z-score on a bone density scan?
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.
What is a good Z-score?
According to the Percentile to Z-Score Calculator, the z-score that corresponds to the 90th percentile is 1.2816. Thus, any student who receives a z-score greater than or equal to 1.2816 would be considered a “good” z-score.
What is a low Z-score?
Probability for this is 0.47% , which is less than half-percent. Note that if z -score rises further, area under the curve fall and probability reduces further. A low z -score means a very low probability of data below this z -score. The figure below shows the probability of z -score below −2.5 .
Is bone age height predictor accurate?
The bone age used is the revised version of the Tanner-Whitehouse standards, omitting the score for carpal bones (RUS age, TW 2 system). Boys aged 4 to 12 are predicted in 95% of instances to within plus or minus 7 cm of true height, and at ages 13 and 14 to within plus or minus 6 cm.
Is bone age accurate?
In a number of conditions involving atypical growth, bone age height predictions are less accurate. For example, in children born small for gestational age who remain short after birth, the bone age is a poor predictor of adult height.
How do I read my bone scan results?
The lower your score, the weaker your bones are:
- T-score of -1.0 or above = normal bone density.
- T-score between -1.0 and -2.5 = low bone density, or osteopenia.
- T-score of -2.5 or lower = osteoporosis.
What z-score tells us?
Z-score indicates how much a given value differs from the standard deviation. The Z-score, or standard score, is the number of standard deviations a given data point lies above or below mean. Standard deviation is essentially a reflection of the amount of variability within a given data set.
