Sweat It Out! The Infant Test For Cystic Fibrosis

Cystic Fibrosis is a genetic condition that affects protein in the body, which causes thickened mucus to form in the lungs, lung infections, and can lead to malnutrition. This condition will eventually limit the ability to breathe. Thickened mucus also forms in the pancreas, and other organs. Most people were diagnosed with Cystic Fibrosis by the age of 2. But thanks to newborn screenings, a person can be diagnosed when they are born, providing faster treatment. If a newborn tested positive in the screening for Cystic Fibrosis, then a chloride sweat test will be ordered

Caucasian baby's legs on hospital bed with diaper on, and pink band around left ankle.
When a baby is born , bloodwork is done, and if the baby has cystic fibrosis, then the doctor will order a sweat test.

by a doctor. This sweat test is considered the “gold standard” for diagnosing Cystic Fibrosis. Conducting this test will diagnose the condition, resulting in a treatment plan to manage it, and improve the quality of life.

What Is The Sweat Test?

The sweat test can be used for all ages, but it is usually done on babies and infants. When a baby is born, routine blood work is done, and if the bloodwork comes back positive for Cystic Fibrosis, then a sweat test is conducted. If an older child experiences trouble breathing, frequent coughing, not being able to gain weight, or salty-tasting skin, then their testing is needed. If both parents have the Cystic Fibrosis gene, then the child will have the condition, but if only one parent has it, then the child will most likely not have it.

The chloride sweat test measures the amount of chloride in sweat. If a kid has Cystic Fibrosis, then their sweat will contain 2-5 times the normal chloride amount. Once the sample is collected by a trained technician, it is tested in a laboratory.

What To Expect During The Test

A suitable sample is needed to perform the chloride sweat test, but a newborn may not produce the desired amount t. In this case, the test will be done again. There is no prepping for it, and no needles are involved. There are no known risks, but what does the test entail?

  1. First, an area of skin on the arm will be washed and dried.
  2. Next, a health provider puts a colorless, odorless chemical called
    Test tubes of all different sizes lined up next to each other.
    After the baby’s sweat is collected in a tube, it is sent out to the lab to be tested for cystyic fibrosis.

    pilocarpine on the area. This medicine induces sweat.

  3. Then, two electrodes are attached with straps holding them in place.
  4. A weak current will be sent through the electrodes, making the medicine seep into the skin. The baby/kid will feel a slight tingling or tickling sensation.
  5. The electrodes are removed and the skin is cleaned.
  6. Finally, a special sweat collection device is taped to the skin, collecting sweat for 30 minutes.
  7. The collected sweat is then placed in an analyzer and sent to the lab.
  8. The arm is then cleaned again, and it is over!

The Results

The results are usually available within a day or two. If the sweat’s chloride level is less than or equal to 20 mmol/L (millimoles per litre), then the condition is unlikely. If the chloride level is between 30-59 mmol/L, then Cystic Fibrosis is possible, and further testing may be necessary. If the chloride levels are greater than or equal to 60 mmol/L, then it is indicative of Cystic Fibrosis.

Some doctors will require further testing to confirm or rule out a diagnosis of Cystic Fibrosis. If the baby/kid does have high chloride levels, then they will be diagnosed with Cystic Fibrosis, and a treatment plan will be created. This can include medication, nutritional therapies, and airway clearance. People with Cystic Fibrosis are living longer, higher quality lives because of the range of treatment options.