21-hydroxylase deficiency screening
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Congenital adrenal hyperplasia due to 21-hydroxylase deficiency Microchapters |
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Differentiating Congenital adrenal hyperplasia due to 21-hydroxylase deficiency from other Diseases |
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Diagnosis |
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Treatment |
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Case Studies |
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21-hydroxylase deficiency screening On the Web |
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American Roentgen Ray Society Images of 21-hydroxylase deficiency screening |
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Directions to Hospitals Treating Congenital adrenal hyperplasia due to 21-hydroxylase deficiency |
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Risk calculators and risk factors for 21-hydroxylase deficiency screening |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Ahmad Al Maradni, M.D. [2]
Overview
While the 17OHP level is easy to measure and sensitive, it has poorer specificity for congenital adrenal hyperplasia.
Screening
Newborn screening
Conditions justifying newborn screening for any disorder include (1) a simple test with an acceptable sensitivity and specificity, (2) a dire consequence if not diagnosed early, (3) an effective treatment if diagnosed, and (4) a frequency in the population high enough to justify the expense. In the last decade more states and countries are adopting newborn screening for salt-wasting congenital adrenal hyperplasia due to 21-hydroxylase deficiency, which leads to death in the first month of life if not recognized.
The screening test itself is less than perfect. While the 17OHP level is easy to measure and sensitive (rarely missing real cases), the test has a poorer specificity. Screening programs in the United States have reported that 99% of positive screens turn out to be false positives upon investigation of the infant. This is a higher rate of false positives than the screening tests for many other congenital metabolic diseases. While each screen costs less than US$2, the program costs well over US$100,000 for each case detected.
When a positive result is detected, the infant's family and doctor must be notified, and the infant must be referred to a pediatric endocrinologist to confirm or disprove the diagnosis. Since most infants with salt-wasting congenital adrenal hyperplasia become critically ill by 2 weeks of age, the evaluation must be done rapidly despite the high false positive rate.