What does immunoreactive trypsinogen measure?
Immunoreactive trypsinogen (IRT) is used as part of some newborn screening programs to screen for cystic fibrosis (CF). It may be used in conjunction with a sweat chloride test and/or a cystic fibrosis gene mutation panel to help identify CF. IRT may also sometimes be used to help detect acute pancreatitis.
What is elevated immunoreactive trypsinogen?
If an IRT level is elevated, a newborn may have cystic fibrosis (CF). If the IRT is elevated, a child or adult may have abnormal pancreatic enzyme production, pancreatitis, or pancreatic cancer.
Why is immunoreactive trypsinogen elevated in CF?
The concentration of IRT is elevated in babies with CF since pancreatic ducts are partially blocked leading to abnormal enzyme drainage. Heterozygous carriers of cystic fibrosis can cause a raised IRT and it is therefore not diagnostic in isolation.
What is a normal IRT level?
The mean IRT level was 79.16 ng/mL (range, 60–367). Table 2 presents the mean levels of IRT in each subgroup of patients, with a mean of 75.66 ng/mL in healthy infants, 78.19 ng/mL in healthy carriers, 93.53 ng/mL in CFSPID cases and 175.82 ng/mL in CF cases.
How do you test for cystic fibrosis?
How is cystic fibrosis diagnosed?
- Blood tests. These may include pancreatic function tests.
- Chest X-rays. This test uses invisible electromagnetic energy beams to makes images of internal tissues, bones, and organs onto film.
- Pulmonary function tests.
- Sputum cultures.
- Stool evaluations.
What is the newborn screening test for cystic fibrosis?
Every state’s CF newborn screening program begins with a blood test from the baby to check the levels of a chemical made by the pancreas called immunoreactive trypsinogen (IRT). IRT is normally found in small levels in the body.
What can cause high IRT levels in newborn?
IRT, which is produced by the pancreas, is a chemical in the blood that is normally found in small levels in the body. If the IRT level is high, this may indicate that the baby has CF, however, levels can also be high if a baby is premature, has had a stressful delivery or for other reasons.
What does borderline CF mean?
A borderline sweat test result—when the chloride level is between 30 and 60—means your child may have a metabolic syndrome related to an abnormal cystic fibrosis transmembrane conductance (CFTR) gene.
At what age is CF diagnosed?
Although most people are diagnosed with CF by the age of 2, some are diagnosed as adults. A CF specialist can order a sweat test. Measures the salt (sodium and chloride) in sweat. and recommend additional testing to confirm a CF diagnosis.
What is considered elevated IRT?
ELEVATED IRT (between 66 and 149) – NO MUTATION DETECTED When IRT is elevated, DNA testing will be performed using a panel of 46 mutations.
How accurate is the IRT test?
Interpreting test results If the initial IRT test is positive, a second IRT test at two weeks after birth, or a DNA test, is carried out to confirm the results. The choice differs by state in the U.S., but both options allow a diagnosis with a success rate of at least 90%.
How do you read cystic fibrosis test results?
To understand what the sweat test results mean, a chloride level of:
- Less than or equal to 29 mmol/L = CF is unlikely regardless of age*.
- Between 30 – 59 mmol/L = CF is possible and additional testing is needed.
- Greater than or equal to 60 mmol/L = CF is likely.