title: Determination of glucose-6-phosphate dehydrogenase cut-off values in a Tunisian population.
abstract: BACKGROUND
  Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the commonest enzymopathy worldwide. The incidence depends essentially on the methods used for the assessment. In this respect, we attempted in this study to set cut-off values of G6PD activity to discriminate among normal, heterozygous, and deficient individuals using the World Health Organization (WHO) classification and the receiver operating characteristics (ROC) curve analysis.
  
  
  METHODS
  Blood samples from 250 female and 302 male subjects were enrolled in this study. The G6PD activity was determined using a quantitative assay. The common G6PD mutations in Tunisia were determined using the amplification refractory mutation system (ARMS-PCR) method. The ROC curve was used to choice the best cut-off.
  
  
  RESULTS
  Normal G6PD values were 7.69±2.37, 7.86±2.39, and 7.51±2.35 U/g Hb for the entire, male, and female groups, respectively. Cut-off values for the total, male, and female were determined using the WHO classification and ROC curves analysis. In the male population, both cut-offs established using ROC curve analysis (4.00 U/g Hb) and the 60% level (3.82 U/g Hb), respectively are sensitive and specific resulting in a good efficiency of discrimination between deficient and normal males. For the female group the ROC cut-off (5.84 U/g Hb) seems better than the 60% level cut-off (3.88 U/g Hb) to discriminate between normal and heterozygote or homozygote women with higher Youden Index.
  
  
  CONCLUSIONS
  The establishment of the normal values for a population is important for a better evaluation of the assay result. The ROC curve analysis is an alternative method to determine the status of patients since it correlates DNA analysis and G6PD activity.
authors.affiliation: .
authors.forename: Naouel
authors.initials: N
authors.lastname: Laouini
authors.affiliation: .
authors.forename: Chaima Abdelhafidh
authors.initials: CA
authors.lastname: Sahli
authors.affiliation: .
authors.forename: Latifa
authors.initials: L
authors.lastname: Jouini
authors.affiliation: .
authors.forename: Sabrine
authors.initials: S
authors.lastname: Haloui
authors.affiliation: .
authors.forename: Sondes Hadj
authors.initials: SH
authors.lastname: Fredj
authors.affiliation: .
authors.forename: Rym
authors.initials: R
authors.lastname: Daboubi
authors.affiliation: .
authors.forename: Hajer
authors.initials: H
authors.lastname: Siala
authors.affiliation: .
authors.forename: Faida
authors.initials: F
authors.lastname: Ouali
authors.affiliation: .
authors.forename: Meriam
authors.initials: M
authors.lastname: Becher
authors.affiliation: .
authors.forename: Nourelhouda
authors.initials: N
authors.lastname: Toumi
authors.affiliation: .
authors.forename: Amina
authors.initials: A
authors.lastname: Bibi
authors.affiliation: .
authors.forename: Taieb
authors.initials: T
authors.lastname: Messsaoud
mesh_terms: D000293:Adolescent; D000328:Adult; D001774:Blood Chemical Analysis / Q000592:standards*; D002648:Child; D005260:Female; D005838:Genotype; D005954:Glucosephosphate Dehydrogenase / Q000097:blood* / Q000235:genetics; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000097:blood / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D008297:Male; D012016:Reference Values; D014416:Tunisia; D055815:Young Adult
chemical_list: D005954:Glucosephosphate Dehydrogenase
keywords: G6PD; cut-off values; glucose-6-phosphate dehydrogenase; molecular diagnosis