Re-Evaluation of Neonatal Screening Tests for Inborn Errors of
Metabolism with Dried Filter Paper Blood Spots

Shim, Kye Shik; Hwang, Jin Soon; Lim, Jung Sub; Kim, Se Young; Shin, Choong Ho; Yang, Sei Won; Choi, Jung Hwan; Yun, Chong Ku; Song, Jung-Han

Original Article

Journal of the Korean Pediatric Society 1999;42(12):1639-1644.
Published online December 15, 1999.

Re-Evaluation of Neonatal Screening Tests for Inborn Errors of Metabolism with Dried Filter Paper Blood Spots

Kye Shik Shim¹, Jin Soon Hwang¹, Jung Sub Lim¹, Se Young Kim¹, Choong Ho Shin¹, Sei Won Yang¹, Jung Hwan Choi¹, Chong Ku Yun¹, Jung-Han Song²

¹Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Korea
²Department of Clinical Pathology, College of M edicine, Seoul National University, Seoul, Korea

여과지 검체에 의한 신생아 선천성 대사이상 선별검사의 재평가

심계식^¹^, 황진순^¹^, 임중섭^¹^, 김세영^¹^, 신충호^¹^, 양세원^¹^, 최중환^¹^, 윤종구^¹^, 송정한^²

^¹서울대학교 의과대학 소아과학교실
^²서울대학교 의과대학 임상병리과학교실

Correspondence:
Kye Shik Shim, Email: 1

Abstract

Purpose
: There have been high rates of false positive and recall in neonatal screening test using the cut-off points set by the manufacturing company. So, it is necessary to re-evaluate the cut off values to minimize the false positive rates.
Methods
: We collected capillary blood in dry filter paper from 996 healthy neonates on the third day in cases of normal vaginal delivery or the fifth day in cases of Cesarean section. The levels of phenylalanine, galactose, 17-hydroxyprogesterone and branched-chain amino acids were measured using enzyme immunoassay. The results were compared with the original cut-off points set by the manufacturing company.
Results
: The original cut-off points of four substances were 4.0mg/dL, 7.5mg/dL, 35ng/mL, and 8.0mg/dL, respectively, so that false-positive rates were 0.4, 1.6, 3.93, and 0.001%, respectively. When we set the cut-off point at 99.7 percentile using the data from healthy neonates, they should be 4.0mg/dL, 9.2mg/dL, 54.3ng/mL, and 8.0mg/dL, respectively. Conclusion : The false-positive and recall rates were higher in galactosemia and congenital adrenal hyperplasia when using the original cut-off points, suggesting that it would be reasonable to modify the cut-off point at 99.7 percentile after measuring those substances from enough of healthy neonates.

Key Words: Neonatal screening test, Cut-off point