Testing & Diagnosis for Congenital Adrenal Hyperplasia (CAH) in Children

The first step in treating a child with congenital adrenal hyperplasia (CAH) is forming an accurate diagnosis. A baby can be diagnosed with CAH during pregnancy and the sex of the after birth, when a through physical examination and a series of tests are performed.

How is CAH diagnosed?

CAH can sometimes be detected and diagnosed during pregnancy through various prenatal tests. In some cases where there is a family history of CAH, treatment can be started when the baby is still in the womb to prevent the maculinizing effects on the female

Why are prenatal tests used?

Prenatal tests are various tests that are performed during pregnancy that identify a baby’s sex, age, size and placement in the uterus. Prenatal tests also detect some chromosomal abnormalities, congenital heart defects and other genetic problems.

Before any parent decides whether or not to get prenatal testing, it’s important to know all the options and the advantages and disadvantages of each one. The two types of prenatal tests used to detect and diagnosis CAH are called screening tests and diagnostic tests.

Screening Tests

Screening tests determine what the chances are that a baby will be born with CAH or other birth defects.

The different types of screening tests for CAH include:

  • Chorionic villus sampling (CVS), a prenatal diagnosis method in which a small biopsy of the placenta is taken for specific genetic testing. CVS is used to detect any condition that involves specific chromosomal abnormalities, like Down syndrome. This test is usually performed during the first trimester.
  • ultrasound, which is a non-invasive imagining technique that uses sound waves to generate an image of the fetus. An ultrasound can identify structural abnormalities that may indicate a diagnosis of CAH.

Diagnostic tests

Diagnostic tests are used after a baby is born. These tests can confirm a diagnosis of CAH and help determine the baby’s sex.

Tests to diagnose CAH:

  • physical exams are used to evaluate a baby’s symptoms. If a doctor suspects CAH based on findings such as ambiguous genitalia, next step is to confirm the diagnosis with a blood test and ultrasound.
  • blood tests measure levels of the hormones produced by the adrenal gland—cortisol, aldosterone and androgen. A diagnosis can be made based on abnormal levels of these hormones.
  • karyotypingis a specific type of blood analysis that allows doctors to determine the genetic sex of the baby by measuring sex hormones in the blood.