title: Interpretation of alpha-fetoprotein concentrations in cerebrospinal fluid of infants.
abstract: BACKGROUND
  There are no published reference intervals for concentrations of alpha-fetoprotein (AFP) in the cerebrospinal fluid (CSF) of normal infants. The presence of abnormal concentrations of AFP in plasma or CSF may indicate the presence of a teratoma or a germ cell tumour with yolk sac elements. We measured CSF AFP in infants who did not have malignancy in order to determine its reference intervals.
  
  
  METHODS
  AFP was measured in the CSF and/or plasma in 128 infants. Of these, 91 infants had CSF AFP measurements, 94 infants had plasma AFP measurements and in 60 infants AFP concentrations were determined in paired CSF and plasma samples. The patients ranged in age from 1 to 110 days. Both CSF and plasma AFP concentrations were measured by a microparticle enzyme immunoassay using an AxSYM analyser.
  
  
  RESULTS
  Using ages corrected for prematurity, the median CSF AFP concentration for babies -69 to 31 days old was 61 kIU/L (5th-95th centile: 2-889 kIU/L), while the median CSF AFP concentration for infants 32 to 110 days was 1.2 kIU/L (5th-95th centile: 0.1-12.5 kIU/L). By age 6 weeks, the concentrations were close to those found in adult plasma and all CSF AFP concentrations from infants with a corrected age over 2 months were <3 kIU/L.
  
  
  CONCLUSIONS
  We have defined reference intervals for CSF AFP concentrations in infants. These results may assist in the diagnosis of CNS tumours, particularly congenital CNS tumours containing yolk sac elements.
authors.affiliation: Department of Clinical Biochemistry, The Children's Hospital at Westmead, Sydney, Australia. johnc2@chw.edu.au
authors.forename: J
authors.initials: J
authors.lastname: Coakley
authors.forename: S J
authors.initials: SJ
authors.lastname: Kellie
authors.forename: C
authors.initials: C
authors.lastname: Nath
authors.forename: A
authors.initials: A
authors.lastname: Munas
authors.forename: C
authors.initials: C
authors.lastname: Cooke-Yarborough
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D012016:Reference Values; D000509:alpha-Fetoproteins / Q000134:cerebrospinal fluid* / Q000378:metabolism
chemical_list: D000509:alpha-Fetoproteins