title: Determination of optimal cutoff value to accurately identify glucose-6-phosphate dehydrogenase-deficient heterozygous female neonates.
abstract: BACKGROUND
  Conventional screening tests to assess G6PD deficiency use a low cutoff value of 2.10 U/gHb which may not be adequate for detecting females with heterozygous deficiency. The aim of present study was to determine an appropriate cutoff value with increased sensitivity in identifying G6PD-deficient heterozygous females.
  
  
  METHODS
  G6PD activity analysis was performed on 51,747 neonates using semi-quantitative fluorescent spot test. Neonates suspected with G6PD deficiency were further analyzed using quantitatively enzymatic assay and for common G6PD mutations. The cutoff values of G6PD activity were estimated using the receiver operating characteristic curve.
  
  
  RESULTS
  Our results demonstrated that using 2.10 U/g Hb as a cutoff, the sensitivity of the assay to detect female neonates with G6PD heterozygous deficiency was 83.3%, as compared with 97.6% using 2.55 U/g Hb as a cutoff. The high cutoff identified 21% (8/38) of the female neonates with partial G6PD deficiency which were not detected with 2.10 U/g Hb. Our study found that high cutoffs, 2.35 and 2.55 U/g Hb, would increase assay's sensitivity to identify male and female G6PD deficiency neonates, respectively.
  
  
  CONCLUSIONS
  We established a reliable cutoff value of G6PD activity with increased sensitivity in identifying female newborns with partial G6PD deficiency.
authors.affiliation: Center for Clinical Molecular Medicine, Children's Hospital of Chongqing Medical University, Chongqing, China; Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.
authors.forename: Jing-Kun
authors.initials: JK
authors.lastname: Miao
authors.forename: Qi-Xiong
authors.initials: QX
authors.lastname: Chen
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Bao
authors.forename: Yi
authors.initials: Y
authors.lastname: Huang
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Ke-Xing
authors.initials: KX
authors.lastname: Wan
authors.forename: Jing
authors.initials: J
authors.lastname: Yi
authors.forename: Shi-Yi
authors.initials: SY
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Zou
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Li
mesh_terms: D002681:China / Q000453:epidemiology; D059788:Dried Blood Spot Testing; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000097:blood* / Q000235:genetics; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D015997:Neonatal Screening; D015995:Prevalence; D012372:ROC Curve
chemical_list: D005954:Glucosephosphate Dehydrogenase
keywords: ARMS; Cut-off value; Female; G6PD; G6PD deficiency; Heterozygotes; Newborn screening; ROC; amplification refractory mutation system; glucose-6-phosphate-dehydrogenase; receiver operating characteristic