title: Limited usefulness of the test of spontaneous growth hormone (GH) nocturnal secretion as a screening procedure in diagnosing GH deficiency in children with short stature.
abstract: OBJECTIVE
  In Poland, the assessment of nocturnal GH secretion has gained the status of screening test; however, this procedure is not included in international recommendations. The aim of the study was to assess the accuracy and predictive value of the test of nocturnal GH secretion as a screening procedure in diagnosing GHD, and to check the adequacy of the cut-off value for GH peak in this test on the level of 10 ng/ml.
  
  
  METHODS
  The analysis comprised the data of 1,000 children with short stature. In all the patients, GH secretion was assessed in a screening test (after falling asleep) and in 2 stimulating tests (reference tests), with simultaneous assessment of IGF-I secretion before stimulating tests. The indices of screening test accuracy, likelihood ratios and predictive values were assessed. The cut-off level of GH peak after falling asleep, ensuring its 95% sensitivity, was calculated in ROC curve analysis.
  
  
  RESULTS
  Sensitivity of the screening test was 70.4%, while the specificity--61.2%, positive likelihood ratio--1.842, negative likelihood ratio--0.482, positive predictive value--0.462, negative predictive value--0.812. The sensitivity of the test of GH secretion after falling asleep is too low with respect to the requirements for screening test. The ROC curve analysis showed 95% sensitivity for the screening test on the level of 19.0 ng/ml; however, with a very low specificity--below 25%, thus making this test completely useless as a screening procedure.
  
  
  CONCLUSIONS
  The obtained results strongly contradict the opinion that the assessment of GH secretion after falling asleep should be a screening test in diagnosing GHD in children with short stature.
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Smyczyńska
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Stawerska
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland; Department of Endocrinology and Metabolic Diseases, Medical University of Lodz, Lodz, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Lewiński
authors.affiliation: Department of Endocrinology and Metabolic Diseases, Polish Mother's Memorial Hospital - Research Institute, Lodz, Poland; Department of Pediatric Endocrinology, Medical University of Lodz, Lodz, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Hilczer
mesh_terms: D000293:Adolescent; D002648:Child; D002940:Circadian Rhythm; D004393:Dwarfism, Pituitary / Q000175:diagnosis; D005260:Female; D019382:Human Growth Hormone / Q000172:deficiency* / Q000378:metabolism; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012890:Sleep
chemical_list: D019382:Human Growth Hormone