Phoenix Children’s operates the only full-service clinical laboratory in Arizona dedicated exclusively to pediatric care. We offer comprehensive testing for a wide range of conditions and issues. Our team of board-certified pediatric pathologists performs more than 1.3 million tests annually.

Our services include:

  • Blood tests: Assess components like glucose, electrolytes, and blood counts
  • Microbiology: Identify infections through cultures, microbial nucleic acids, and mass spectrometry
  • Genetic testing: Detect inherited conditions or chromosomal abnormalities
  • Surgical pathology: Analyze tissue samples removed during surgery to diagnose disease and guide treatment
  • Histology: Examine thin slices of tissue under a microscope to study cell structure and detect abnormalities
  • Transfusion services: Provide and manage blood products for patients in need
  • Specialized tests: Includes sweat chloride tests for cystic fibrosis (CF) and hydrogen breath tests for gastrointestinal issues

Sweat Chloride Tests

Sweat tests are the standard tests used to diagnose cystic fibrosis. They measure the amount of chloride in your child’s sweat. Chloride is an electrolyte that helps maintain the normal function of your child’s airway and digestive tract. Phoenix Children’s is accredited by the Cystic Fibrosis Foundation to provide state-of-the-art diagnostic and treatment regimens for children with cystic fibrosis.

We use sweat tests to assess sweat chloride for cystic fibrosis if:

  • Your baby shows signs of cystic fibrosis during their newborn screenings.
  • Your child is exhibiting symptoms of cystic fibrosis
  • Your family has a history of cystic fibrosis.

A sweat test typically takes about an hour to complete. It does not require special preparation, but your child should be well hydrated and well fed. Application of lotions and creams to your baby’s skin within 24 hours of the test should be avoided.

During the sweat test, one of our healthcare professionals will collect a sweat sample from your child. They may feel a tickling sensation or mild tingling, but your child should not experience any pain during the test.

The test typically includes the following steps:

  • Your child’s provider will wash and dry a small area of your child’s leg or forearm.
  • The provider will then apply a chemical called pilocarpine and tape an electrode to the cleaned area.
  • Pilocarpine is delivered into the skin by a weak electrical current to promote sweat production.
  • We remove the electrode after five minutes, then collect sweat for 30 minutes using a plastic coil. 
  • The Phoenix Children’s laboratory analyzes the sweat sample and shares the results with your child’s doctor.

Hydrogen Breath Tests

We use hydrogen breath tests to diagnose abnormalities in sugar absorption and metabolism such as lactose intolerance. They measure the amount of hydrogen gas in your child’s breath before and after they drink a liquid containing sugar. High hydrogen levels often indicate an abnormality.

Hydrogen breath tests may help in the diagnosis of:

  • Sugar Malabsorption including lactose, fructose, sucrose, or sorbitol.
  • Celiac disease: An autoimmune condition that causes a reaction to gluten, causing damage to the small intestine.
  • Crohn’s disease: A chronic inflammatory bowel disease (IBD) that affects the gastrointestinal tract.
  • Irritable bowel syndrome (IBS): A common condition that affects the stomach and intestines.
  • Small intestinal bacterial overgrowth (SIBO): Causes excess bacteria to form in your child’s intestine.
  • Ulcerative colitis: An inflammatory bowel disease (IBD) that causes inflammation in the inner lining of the large intestine and rectum.

The test is noninvasive and does not hurt. Your child may experience mild cramps or bloating after drinking the sugar-containing liquid, but these symptoms are temporary and usually go away quickly.

Certain medications, foods, and activities can affect the results of a hydrogen breath test. Your child’s provider will ask you to follow specific guidelines during the weeks, days, and hours before your child’s appointment.

During the test, your child will:

  • Breathe into a balloon-type container that measures the amount of hydrogen in their breath.
  • Drink a flavored liquid containing sugar.
  • Breathe into the container again after 30 minutes and every 30 minutes for several hours.

We measure your child’s hydrogen levels at each interval and report the results to your child’s doctor.