IRT
Pronunciation: I-R-T
Also written as: IRT — immunoreactive trypsinogen
Immunoreactive trypsinogen, a pancreatic enzyme measured in newborn screening to detect cystic fibrosis.
Full Definition
Immunoreactive trypsinogen is a pancreatic enzyme that becomes elevated in the blood of newborns with cystic fibrosis due to pancreatic duct obstruction and inflammation. IRT measurement is the primary first-tier screening test for cystic fibrosis in most newborn screening programs. Elevated IRT levels trigger second-tier testing, which may include DNA analysis for CFTR mutations or repeat IRT measurement. The test has high sensitivity but moderate specificity, requiring careful follow-up protocols to minimize false positives.
Usage
Usage note: Always capitalize all letters. Define the full term on first use in patient communications.
In Context
- "An elevated IRT level on newborn screening prompted immediate genetic testing for cystic fibrosis mutations." — Laboratory report interpretation
- "The IRT cutoff values must be regularly calibrated to maintain optimal sensitivity and specificity for cystic fibrosis detection." — Quality assurance protocol