title: Prevalence and long-term course of macro-aspartate aminotransferase in children.
abstract: OBJECTIVE
  To investigate the prevalence, association with clinical conditions, and long-term course of macro-aspartate aminotransferase (macro-AST).
  
  
  METHODS
  Forty-four children with an isolated elevation of serum AST were screened for macro-AST with electrophoresis and % polyethylene glycol (PEG) precipitable activity (PPA).
  
  
  RESULTS
  All children were healthy, except they had elevated AST values. Seventeen children (38.6%) were macro-AST-positive. They had higher AST values than the 27 children who were macro-AST-negative (P = .001). Values <67.1% PPA and >82.2% PPA were associated with a very low probability of being macro-AST-positive and macro-AST-negative, respectively. Thirty-eight children underwent clinical and laboratory follow-up (mean, 4.7 +/- 3.8; range, 1-16 years). All remained symptom-free. AST levels decreased significantly only in children who were macro-AST-negative (P = .006). Macroenzyme persisted in 6 of the 9 children who were macro-AST-positive after 6.0 +/- 4.1 years.
  
  
  CONCLUSIONS
  Macro-AST was present in more than one-third of children with an isolated increase of AST levels. The lack of pathological correlates in a long period argues for the benign nature of this phenomenon in childhood. We suggest that our %PPA thresholds can be used as a screening test and that electrophoresis be reserved for confirming positive screen test results and cases in which %PPA levels are of intermediate discriminant accuracy.
authors.affiliation: Department of Pediatrics, University of Naples Federico II, Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Caropreso
authors.forename: Giuliana
authors.initials: G
authors.lastname: Fortunato
authors.forename: Selvaggia
authors.initials: S
authors.lastname: Lenta
authors.forename: Daniela
authors.initials: D
authors.lastname: Palmieri
authors.forename: Marianna
authors.initials: M
authors.lastname: Esposito
authors.forename: Dino Franco
authors.initials: DF
authors.lastname: Vitale
authors.forename: Raffaele
authors.initials: R
authors.lastname: Iorio
authors.forename: Pietro
authors.initials: P
authors.lastname: Vajro
mesh_terms: D000293:Adolescent; D001219:Aspartate Aminotransferases / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004586:Electrophoresis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D011092:Polyethylene Glycols / Q000737:chemistry; D015995:Prevalence; D012680:Sensitivity and Specificity
chemical_list: D011092:Polyethylene Glycols; D001219:Aspartate Aminotransferases