Cystic Fibrosis Diagnosis
Exam and Test
All newborns in Virginia are screened for cystic fibrosis. This preliminary blood test measures the level of immunoreactive trypsinogen (IRT) present in the blood.
Definition of IRT
Trypsinogen is one of the secretory products of the pancreas making its level in the blood a specific marker of pancreatic function. Elevated levels of IRT indicate that a newborn may be at risk for CF.
Why is this test performed?
After many years of following patients with cystic fibrosis who had newborn
screening, it was determined that growth and nutrition improved, survival improved and need for hospitalization decreased. Therefore, the Morbidity and Mortality Weekly Report in 10/15/04 stated
the health benefits from screening "outweigh the risk of harm and justify
newborn screening for cystic fibrosis”. Newborn screening in the Commonwealth of
Virginia begin in March 2006.
How is this test performed?
This test is included with all other tests done for newborn screening and noted on the newborn screening card that
your childre receives before discharge from the hospital or by your primary care physician.
What is done if your child has an abnormal test result?
If the first newborn screen test is abnormal, your primary care physician will order a repeat newborn screen test. If that second test is also abnormal, diagnostic testing is required. This test is usually a
sweat chloride test.