From the Research
Normal cortisol levels for a 9-year-old female typically range from 81.9-645.5 nmol/L in the morning. Cortisol follows a diurnal pattern, with highest levels in the early morning and lowest levels at night, which is why the time of collection is crucial for proper interpretation. For accurate assessment, morning samples are preferred and should be collected between 8-10 AM. Stress, illness, medications (particularly steroids), and even the stress of blood collection itself can affect cortisol levels. If abnormal values are found, repeat testing or more comprehensive evaluation such as a 24-hour urinary cortisol or ACTH stimulation test may be needed. Some key points to consider when evaluating cortisol levels include:
- The impact of age and pubertal maturation on cortisol levels, as shown in a study published in 2015 1
- The importance of considering the diurnal pattern of cortisol secretion when interpreting test results
- The potential effects of various factors, such as stress and medications, on cortisol levels Normal cortisol production is essential for proper glucose metabolism, immune function, and stress response in children. Values outside these ranges should be interpreted in the clinical context by a pediatric endocrinologist, as both abnormally high cortisol (Cushing syndrome) and low cortisol (adrenal insufficiency) can have significant health implications. It is also worth noting that the reference values for cortisol may vary depending on the laboratory and the specific assay used, as discussed in a study published in 2012 2. However, the study by 1 provides the most relevant and recent guidance on normal cortisol levels in children.