Abstract | BACKGROUND: Availability of the galactose-1-phosphate uridyltransferase (GALT) assay for newborn (NB) screening has improved identification of classic galactosemia. Previously defined critical cutoffs for total galactose (Gal), typically 1.110 mmol/L (20 mg/dL), are still in use in laboratories measuring total Gal for the diagnosis of nonclassic galactosemias. Urgent notification/referral to a treatment center follows, although few of the NBs will need treatment. METHODS: We reviewed all NB galactosemia-screening results and their corresponding clinical outcomes over a 5-year period (first phase, 1.32 x 10(6) NBs) and then over a 2-year period (second phase, 274 960 NBs). Each NB was screened for Gal and GALT. When Gal was increased and/or GALT was deficient, testing for percentage galactose-1-phosphate and/or DNA testing for common GALT mutations were performed. RESULTS: Of 209 reported positive results, 89% did not indicate GALT deficiency. These non-GALT-deficient results represented mostly clinically benign cases with a Gal threshold of > or = 1.110 mmol/L (> or = 20 mg/dL). The positive predictive value of a GALT cutoff of < or = 40 micromol/L was 83%. After a protocol change that redefined a critical result as a GALT value < or = 40 micromol/L and/or a Gal value > or = 1.665 mmol/L (> or = 30 mg/dL), results were monitored for an additional 2 years. The new protocol dramatically reduced the number of urgent calls/referrals and reduced the total number of referrals by nearly half. CONCLUSIONS: Use of a GALT cutoff of < or = 40 micromol/L/L and a Gal cutoff of > or = 1.665 mmol/L (> or = 30 mg/dL) for urgent notification/referral dramatically reduces false positives and unnecessary follow-up, thereby reducing the stress on healthcare resources.
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Authors | Dennis E Freer, Can Ficicioglu, David Finegold |
Journal | Clinical chemistry
(Clin Chem)
Vol. 56
Issue 3
Pg. 437-44
(Mar 2010)
ISSN: 1530-8561 [Electronic] England |
PMID | 20075179
(Publication Type: Journal Article)
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Chemical References |
- DNA
- UTP-Hexose-1-Phosphate Uridylyltransferase
- Galactose
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Topics |
- DNA
(genetics)
- Galactose
(blood)
- Galactosemias
(diagnosis, genetics)
- Humans
- Infant, Newborn
- Mutation
- Neonatal Screening
(methods)
- UTP-Hexose-1-Phosphate Uridylyltransferase
(blood, genetics)
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