What labs are used for monitoring Congenital Adrenal Hyperplasia (CAH)?

From the Guidelines

Laboratory monitoring for congenital adrenal hyperplasia (CAH) should include measuring 17-hydroxyprogesterone (17-OHP), androstenedione, testosterone, plasma renin activity, and electrolytes, with the goal of maintaining 17-OHP levels between 400-1200 ng/dL and androstenedione/testosterone in the mid-normal range for age and sex, as recommended by recent guidelines 1. When monitoring for adrenal hyperplasia, it is essential to consider the following key laboratory tests:

• 17-hydroxyprogesterone (17-OHP)
• Androstenedione
• Testosterone
• Plasma renin activity
• Electrolytes (sodium, potassium) These tests should be checked regularly, with the frequency depending on the patient's age, disease severity, and treatment regimen. For example, patients with classic CAH may require laboratory monitoring every 3-4 months, with more frequent monitoring during infancy, periods of poor control, or after medication adjustments 1. In terms of specific laboratory targets, the goal is to maintain:
• 17-OHP levels between 400-1200 ng/dL
• Androstenedione/testosterone in the mid-normal range for age and sex
• Plasma renin activity in the upper normal range, indicating adequate mineralocorticoid replacement
• Electrolytes (sodium, potassium) within normal ranges to detect mineralocorticoid deficiency, especially in salt-wasting CAH 1. Annual bone age assessments are also recommended for children to monitor growth and development. By regularly monitoring these laboratory values, clinicians can adjust medication doses appropriately, balancing adequate hormone replacement while avoiding overtreatment, which can lead to cushingoid features, growth suppression, and metabolic complications 1.

From the Research

Labs for Adrenal Hyperplasia Monitoring

• The management of patients with congenital adrenal hyperplasia (CAH) involves monitoring of serum cortisol and 17-hydroxyprogesterone levels to assess the adequacy of glucocorticoid replacement therapy 2.
• Blood investigations should include androstenedione and 17-hydroxyprogesterone concentrations determined in the morning before the administration of hydrocortisone 2.
• A 4-hour profile of serum 17-hydroxyprogesterone may not be useful in predicting hyperandrogenemia, and suppressed levels of 17-hydroxyprogesterone do not always indicate overtreatment 3.
• Reference intervals of 17-hydroxyprogesterone for different time periods might be of importance, and low hydrocortisone doses should be avoided 3.
• Sex hormone-binding globulin (SHBG) could be used in pubertal children as an indicator of hyperandrogenemia 3.

Biomarkers for Monitoring

• 17-hydroxyprogesterone (17-OHP) is a key biomarker for monitoring CAH, and its levels can be measured in serum or saliva 2, 3, 4.
• Androstenedione is another biomarker that can be used to monitor CAH, and its levels correlate with 17-OHP levels 2, 5, 4.
• Cortisol levels can also be measured to assess the adequacy of glucocorticoid replacement therapy 2, 5.

Timing of Lab Tests

• Lab tests should be performed in the morning before the administration of hydrocortisone to assess the baseline levels of 17-OHP and androstenedione 2.
• Serial monitoring of 17-OHP levels may not be necessary, and a single measurement may be sufficient to assess the adequacy of treatment 3.