Measurement of<unk>  <unk>  in blood of newborn babies is an assay in rapidly increasing use as a screening test for cystic fibrosis (CF). In CF, there is poor release from pancreatic ducts.<unk>  is a pancreatic enzyme precursor found in the blood that is elevated in most of those with CF at birth, regardless of whether their mutation is pancreatic sufficient or insufficient. The concentration of<unk>  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<unk>  and it is therefore not diagnostic in isolation.<unk>  is measured in routine heel-prick blood taken for biochemical screening of all newborn infants born in the UK. This test is one of a number of completed in newborn screening (the "Guthrie Test"). In Australia it is known 94% of those with eventual diagnosis of CF have a positive<unk>  on newborn screen. Samples with a raised<unk>  (defined as highest 1% of values) are then screened for common CF gene mutations. Each centre has a slightly different gene panel; currently 40-50 of the most common genes are sequenced. However, there are more than 2000 known mutations, so gene panel testing does miss occasional CF patients. If gene testing finds one mutation they will then have a sweat test to help confirm the diagnosis. Sweat testing is more likely to be equivocal in infants and typically not attempted in those under 5 kg. If sweat test is positive more expansive gene testing is considered. If two mutations are found they are diagnosed with CF. __TOC__
Immunoreactive trypsinogen
Cross-reactive carbohydrate determinants
Anti-gliadin antibodies
Fluorescein-labeled proaerolysin
Cysteine-rich secretory protein
Mutated citrullinated vimentin
Microbiota-accessible carbohydrates
Neurotoxin