Dried Blood Spot Screening for Cystic Fibrosis

Applegarth, D. A.; George, A.; Davidson, F.; Kirby, L T; Bridges, Michael A.; Sorensen, Poul H.; Wong, LawrenceT.-K.; Hardwick, David F.

doi:10.1016/s0140-6736(79)92350-x

Cited by 11 publications

(7 citation statements)

References 4 publications

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“…While results from retrospective assay and Newborn Screening suggest that most or all CF newborn infants have elevated blood IRT, this is not the pattern in the older CF individual. Crossley, Elliott and Smith [8] in their original study found that after the age of 1 year, most CF children have normal or decreased circulating IRT levels and similar results have been reported by others [9,10,14,17,18,19,22,24,40,41]. In two of these patients (patients A & B), it appeared that the peak in IRT levels was not achieved until some time after the first week of life.…”

Section: Evolution Of Irt Levels With Age In Cystic Fibrosissupporting

confidence: 68%

See 1 more Smart Citation

Immunoreactive Trypsin in Cystic Fibrosis

Davidson,

Wong,

Kirby

et al. 1984

J. pediatr. gastroenterol. nutr.

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Section: Evolution Of Irt Levels With Age In Cystic Fibrosissupporting

confidence: 68%

“…Except for the results quoted in our initial report [9], all our dried blood dot and serum IRT assays have been based upon the SORIN materials.…”

Section: S79mentioning

confidence: 99%

Immunoreactive Trypsin in Cystic Fibrosis

Davidson,

Wong,

Kirby

et al. 1984

J. pediatr. gastroenterol. nutr.

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“…Patients with cystic fibrosis (CF) have been found to have elevated immunoreactive trypsin in serum or dried blood spots obtained in the newborn period and during early infancy (2,8,19). In C F children 2 years of age or older, however, Crossley et al (8) found serum immunoreactive trypsin levels to be similar to or slightly below those in other children without CF.…”

Section: Speculationmentioning

confidence: 99%

“…We hav;used a radi;mmunoassay technique developed in this laboratory which can detect circulating cationic trypsinogen as well as trypsin bound to a,-protease inhibitor (al-antitrypsin) (12). In contrast to methods described in other reports (2,8,19), this procedure involves chemical blocking of the active site of the radioiodinated trypsin tracer used in the assay to prevent it from binding to plasma protease inhibitors while maintaining full immunoreactivity.…”

Section: Speculationmentioning

confidence: 99%

Plasma Immunoreactive Pancreatic Cationic Trypsinogen in Cystic Fibrosis: a Sensitive Indicator of Exocrine Pancreatic Dysfunction

et al. 1981

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SummaryPlasma immunoreactive cationic trypsin(ogen) levels were determined in 32 control subjects and 43 patients with varying degrees of pancreatic insufficiency including 35 with cystic fibrosis (CF) and eight with Shwachman's syndrome. In six CF infants less than 2 years of age, plasma trypsin(ogen) levels were significantly elevated (97.3 + 62.2 ng/ml) above the normal range for nine controls (7.0 + 5.9 ng/ml, P < 0.025). Four of these infants had steatorrhea, three of whom had undetectable duodenal trypsin activity after stimulation with secretin-cholecystokinin. In two CF infants, molecular size fractionation by gel filtration of plasma followed by radioimmunoassay of the column fractions demonstrated that trypsinogen was the only immunoreactive species in the circulation.In contrast, in older CF patients with steatorrhea (mean age, 15.3 + 4.6 years), plasma cationic trypsin(ogen) levels were undetectable or low (1.1 2 1.7 ng/ml). This finding clearly distinguished them from older CF patients without steatorrhea (mean age, 14.3 f 3.9 years) in whom cationic trypsin(ogen) levels were significantly higher (23.3 + 17.6 ng/ml; P < 0.01). The mean trypsin(ogen) concentration in the older CF patients without steatorrhea did not differ from the mean value for 23 normal subjects of similar age. Plasma cationic trypsin(ogen) levels in two Shwachman's patients with steatorrhea (0.19 and 0.86 ng/ml) were significantly lower than the values found in six Shwachman's patients without steatorrhea (5.9 + 2.3 ng/ml; P < 0.025). Furthermore, in nine older CF patients and eight Shwachman's patients, circulating trypsin(ogen) levels were highly correlated with duodenal trypsin output after secretin-cholecystokinin stimulation (r = 0.946, P < 0.01; r = 0.899, P < 0.01, respectively). These results suggest that in CF infants high levels of circulating trypsin(ogen) persist even in those with complete pancreatic insufficiency. In older CF patients and those with Shwachman's syndrome, however, circulating trypsin(ogen) accurately reflects residual pancreatic function.

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“…In addition, the level of serum immunoreactive trypsin()gen was found to be high at an early age in CF patients (Crossley et al 1979). This formed the basis of radioimmunoassays to measure IRT in dried blood spots (Applegarth et al 1979;King et al 19791. Different protocols have been developed and found to be suitable for mass screening; for example, a first IRT assay at 3 to 5 days of age followed by a second assay in the case of elevated IRT levels (a two-step IRT protocol).…”

Section: Introductionmentioning

confidence: 99%

Neonatal screening for cystic fibrosis: result of a pilot study using both immunoreactive trypsinogen and cystic fibrosis gene mutation analyses

et al. 1995

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We have evaluated a two-tier neonatal cystic fibrosis (CF) screening of immunoreactive trypsinogen (IRT) followed by CFTR gene mutation analysis using a systematic scanning of exons 7, 10, and 11, and, if necessary, by direct DNA sequencing. Over an 18-month period we screened 32,300 neonates born in the western part of Britanny. The first tier, involving IRT screening at 3 days of age, utilizes a low elevation of the trypsinogen level (600 ng/ml), which is highly sensitive. The second tier, which corresponds to the exhaustive screening for mutations in three exons of the gene, is highly specific for this population (Britanny). The false positive rate is very low, and no false negatives have been reported to date. This strategy has allowed the identification of five novel alleles (V322A, V317A, 1806 del A, R553G, G544S).

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Dried Blood Spot Screening for Cystic Fibrosis

Cited by 11 publications

References 4 publications

Immunoreactive Trypsin in Cystic Fibrosis

Immunoreactive Trypsin in Cystic Fibrosis

Plasma Immunoreactive Pancreatic Cationic Trypsinogen in Cystic Fibrosis: a Sensitive Indicator of Exocrine Pancreatic Dysfunction

Neonatal screening for cystic fibrosis: result of a pilot study using both immunoreactive trypsinogen and cystic fibrosis gene mutation analyses

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