J Korean Soc Pediatr Endocrinol.  2006 Dec;11(2):192-198.

Revaluation of Neonatal Screening Test for Congenital Adrenal Hyperplasia

• Oh KI
• Kim SJ
• Kim DH
• Kim JK
• Jun YH
• Choi JW
• Lee JE

Abstract

PURPOSE: Newborn screening based on measurement of 17alpha-hydroxyprogesterone (17-OHP) in a dried blood spot on filter paper is an effective tool for early diagnosis of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. High levels of 17-OHP are frequently observed in premature infants without CAH. The purpose of this study is to evaluate cut-off limits of 17-OHP on the basis of gestational age and birth weight.
METHODS
A total of 1,218 newborn were screened for CAH by measuring blood spot 17-OHP concentration. An enzyme linked immunosorbent assay (ELISA) method (Bayer(TM), Neonate 17-OHP Kit, Tokyo, Japan) was used. The values were analyzed on the basis of birth weight and gestational age at birth to decide the appropriate cut-off limits in neonatal mass screening for 21-hydroxylase deficiencies.
RESULTS
In the neonatal mass screening for CAH, the median value of 17-OHP in the subject population was 3.13 ng/mL (0-62.3 ng/mL). Median values of 17-OHP of full term infants and premature infants were 2.44 ng/mL (0.03-27.1 ng/mL) and 4.85 ng/mL (0.06-62.3 ng/mL). 17-OHP levels are higher in preterm infants, and decrease in relation to gestational age (P<0.01). When we applied 99.5 percentile, the cutoff levels were 14.05 ng/mL in full term infants and 44.99 ng/mL in preterm infants. Median values of 17-OHP of normal birth weight [birth weight (BW) > or =2,500 g] infants and low birth weight (BW<2,500 g) infants were 2.57 ng/mL (0-32.40 ng/mL) and 5.02 ng/mL (0.06-62.30 ng/mL). 17-OHP levels increased with decreasing birth weight (P<0.01). When we applied 99.5 percentile, the cutoff levels were 18.33 ng/mL in normal birth weight infants and 56.46 ng/mL in low birth weight infants. Recall rates were markedly decreased when these cutoff levels were applied; 30.2-fold decrease in gestational age <30 wks and 8.2-fold decrease in birth weight <1,000 g.
CONCLUSION
The screening for CAH using 17-OHP should be considered on the basis of gestational age and birth weight. Recall rate and false positive rate markedly decrease in preterm infants and low birth weight infants when new cutoff levels of 17-OHP are applied.

Keyword

Congenital adrenal hyperplasia; 17-OHP; Gestational age; Birth weight

MeSH Terms

Adrenal Hyperplasia, Congenital*
Birth Weight
Early Diagnosis
Enzyme-Linked Immunosorbent Assay
Gestational Age
Humans
Infant
Infant, Low Birth Weight
Infant, Newborn
Infant, Premature
Mass Screening
Neonatal Screening*
Parturition
Steroid 21-Hydroxylase
Steroid 21-Hydroxylase