Sweat Test for Cystic Fibrosis

Sweat Test for Cystic Fibrosis

The sweat test for cystic fibrosis (CF) is a simple, painless and noninvasive diagnostic test used to help diagnose and monitor CF. It measures the amount of salt in the patient's sweat and is used to evaluate the body's production of the chloride ion, which is associated with CF.

The sweat test is a simple procedure and is a useful tool in diagnosing and monitoring CF in young patients. The test involves collecting a sample of sweat and then measuring the chloride content. This value is then compared to a reference range to determine if a person has CF or an alternative diagnosis.

Preparation for Sweat Test

Prior to the sweat test, the patient should avoid drinking alcohol, caffeine, or other stimulants. Additionally, ointments or creams must not be used on the area of skin were the test will be performed in order to ensure accurate results.

Procedure of Sweat Test

The sweat test itself typically takes less than an hour. A technician will apply a mild electrical current to a small area of skin, usually on the arm or leg, in order to stimulate sweat production. After about 20 minutes, the area is wiped with a gauze cloth that collects the sweat. The sample is then sent to a laboratory for testing.

Types of Sweat Test

There are two main types of sweat tests used to diagnose CF. The first is the “quick test”, which measures the chloride content in the sample collected and can provide a fast diagnosis. The second is the “quantitative sweat test”, which uses high-precision instruments to measure the exact amount of chloride in the sample.

Risks of Sweat Test

The sweat test is safe and almost painless, with very few risks. The most common risks associated with the test include minor skin irritation and a temporary redness or rash at the site of the sample collection. Additionally, there is a minor risk of an electric shock if a metal object touches the electrodes during the sweat collection.

When and Why is a Sweat Test Used?

The sweat test is generally considered to be the standard method for diagnosing CF in infants and young children and is used to diagnose approximately 90% of all cases. The test is also used to monitor the effects of CF treatments, as well as to diagnose other diseases that may cause similar symptoms.