Bone age is a measure of how mature a person’s bones are based on their appearance on an x-ray. It is not the same as chronological age, which is the amount of time that has elapsed since birth. Bone age can be used to assess a person’s growth and development, as well as to diagnose certain medical conditions that affect bone growth.

How is bone age determined?

The most common way to estimate bone age is to take an x-ray of the left hand and wrist and compare it to a reference atlas that contains x-ray images of the left hands of children of different ages and sexes. A radiologist or a trained professional will look at various features of the bones, such as their size, shape, mineralization, and fusion, and assign a bone age that matches the image in the atlas that most closely resembles the patient’s x-ray.

What are the uses of bone age?

Bone age can be used for several purposes, such as:

• To predict adult height: A child’s current height and bone age can be used to estimate how tall they will be when they stop growing.
• To diagnose growth disorders: A discrepancy between bone age and chronological age can indicate a problem with growth. For example, a bone age that is much younger than chronological age can suggest delayed puberty, growth hormone deficiency, or other causes of short stature. A bone age that is much older than chronological age can suggest precocious puberty, congenital adrenal hyperplasia, or other causes of tall stature.
• To monitor treatment: Bone age can be used to evaluate the effectiveness of treatment for growth disorders, such as growth hormone therapy or puberty blockers.
• To assess legal or non-clinical issues: Bone age can be used to estimate the biological age of a person for legal purposes, such as immigration or sports eligibility. However, this practice is not recommended as it is not very accurate and may have ethical implications.

What are the limitations of bone age?

Bone age is not a perfect measure of biological maturity, as it can be influenced by various factors, such as genetics, nutrition, environment, ethnicity, and diseases. Bone age also has a margin of error and may vary depending on the method and the observer used to estimate it. Therefore, bone age should be interpreted with caution and in conjunction with other clinical and laboratory data.

How is a bone age test done?

A bone age test is a simple and painless procedure that involves taking an x-ray of the left hand and wrist. The x-ray is usually done in a radiology department, imaging center, or doctor’s office. The child will sit on a stool and place their left hand on a table with the fingers spread. They will need to stay still for a few seconds while the x-ray machine takes a picture of their bones. The x-ray image will then be sent to a radiologist or an endocrinologist who will compare it to a reference atlas and assign a bone age to the child.

What are the risks of a bone age test?

A bone age test is a very safe procedure that uses a small amount of radiation to make an image of the bones. The amount of radiation exposure from a single x-ray is much lower than the amount of radiation we are exposed to from natural sources, such as the sun and the soil, every day. The benefits of getting an accurate bone age assessment usually outweigh the potential risks of radiation exposure. However, some precautions should be taken to minimize the radiation exposure, such as wearing a lead apron to protect other parts of the body and avoiding unnecessary or repeated x-rays. Pregnant women and children who have had previous radiation therapy should inform their doctor before having an x-ray.