Diagnosis

CAH may be diagnosed before a baby is born, during childhood or later in life.

Prenatal testing

Tests used to diagnose CAH in fetuses include:

• Amniocentesis. This procedure involves using a needle to withdraw a sample of amniotic fluid from the womb and then examining the cells.
• Chorionic villus sampling. This test involves withdrawing cells from the placenta for examination.

Newborns, infants and children

Doctors recommend that all newborns in the United States be screened for genetic 21-hydroxylase deficiency during the first few days of life. This test identifies the classic form of CAH but doesn't identify the nonclassic form.

Diagnosis of CAH in older children and young adults includes:

• Physical exam. If the doctor suspects CAH based on a physical exam and symptoms, the next step is to confirm the diagnosis with blood and urine tests.
• Blood and urine tests. These tests look for abnormal levels of hormones produced by the adrenal glands.
• Gene testing. In older children and young adults, genetic testing may be needed to diagnose CAH.
• Testing to determine a child's sex. In female infants who have severe ambiguous genitalia, tests can be done to analyze chromosomes to identify genetic sex. Also, pelvic ultrasound can be used to identify the presence of female reproductive structures such as the uterus and ovaries.