title: Luteinizing hormone and follicle-stimulating hormone levels in extreme prematurity: development of reference intervals.
abstract: OBJECTIVE
  Establishing pediatric reference intervals has always been challenging, with most ranges used in pediatric laboratories developed over many years. The clinical interpretation of gonadotropins is important in the context of ambiguous genitalia. The aim of this study was to develop reference intervals for luteinizing hormone and follicle-stimulating hormone in infants born between 24 and 29 weeks' gestation.
  
  
  METHODS
  Samples were collected at 0 to 43 days after birth from 82 premature infants born <30 weeks' gestation for analysis of luteinizing hormone and follicle-stimulating hormone by automated immunochemiluminometric immunoassays.
  
  
  RESULTS
  The 43 male infants demonstrated a range of luteinizing hormone levels from 0.1 to 13.4 IU/L and of follicle-stimulating hormone levels from 0.3 to 4.6 IU/L. The 39 female infants demonstrated a range of luteinizing hormone levels from 0.2 to 54.4 IU/L and of follicle-stimulating hormone levels from 1.2 to 167.0 IU/L. The ratio of luteinizing hormone/follicle-stimulating hormone levels differed with males, ranging from 0.3 to 9.4, and females, at <0.5.
  
  
  CONCLUSIONS
  These data provide guidance for the interpretation of luteinizing hormone and follicle-stimulating hormone levels for the first 6 weeks of life in extremely premature infants born between 24 and 29 weeks' gestation. The availability of age-appropriate reference intervals is essential for correct and timely interpretation of biochemical results to the clinician.
authors.affiliation: Royal Children's Hospital, Complex Biochemistry Department, Parkville, Victoria 3052, Australia. ronda.greaves@rch.org.au
authors.forename: Ronda F
authors.initials: RF
authors.lastname: Greaves
authors.forename: Rodney W
authors.initials: RW
authors.lastname: Hunt
authors.forename: Angela S
authors.initials: AS
authors.lastname: Chiriano
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Zacharin
mesh_terms: D015415:Biomarkers / Q000097:blood; D002657:Child Development / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005640:Follicle Stimulating Hormone / Q000097:blood* / Q000378:metabolism; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D052577:Infant, Extremely Low Birth Weight / Q000097:blood*; D007231:Infant, Newborn; D007234:Infant, Premature; D007986:Luteinizing Hormone / Q000097:blood* / Q000378:metabolism; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D012016:Reference Values; D018570:Risk Assessment; D012494:Sampling Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone