title: [Reference ranges of insulin, insulin like growth factor-1 and adrenocorticotropic hormone in ponies].
abstract: OBJECTIVE
  The aim of this study was to validate a chemiluminescence immunometric assay using the IMMULITE 2000® for the determination of adrenocorticotropic hormone (ACTH), insulin and insulin-like growth factor-1 (IGF-1) from which reference ranges were calculated for ponies.
  
  
  METHODS
  Blood samples of 130 ponies aged 3-32 years were collected in the afternoon. The reference ranges were calculated according to the Guideline EP28-A3C of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) from 2010.
  
  
  RESULTS
  The determined intraday precision for insulin was 3.28%, for ACTH 3.35% and for IGF-1 1.84%. The interday precision (insulin: 3.45%; IGF-1: 2.89%; ACTH: 9.77%) was determined on three consecutive days, where the samples were stored at 4   °C. There was no significant loss of insulin activity nor of ACTH or IGF-1 concentration during this time. The reference ranges of insulin and IGF-1 (2.0-21.2 mU/l and 50.2-357.2 mU/l, respectively) were age independent, whereas for ACTH, an age-dependent reference range was established. Ponies aged 3-12 years had a significantly lower reference range (4.2-19.8 pg/ml) than ponies aged 13-32 years (5.0-22.6 pg/ml).
  
  
  CONCLUSIONS
  The method used is suitable for the determination of ACTH, IGF-1 and insulin in serum of ponies, but the lowest detection limit for insulin is 2.0 mU/l.
  
  
  CONCLUSIONS
  The calculated reference ranges of insulin and ACTH are helpful for the diagnosis and clinical monitoring of equine metabolic syndrome and pituitary pars intermedia dysfunction (PPID).
authors.forename: G
authors.initials: G
authors.lastname: Köller
authors.forename: K
authors.initials: K
authors.lastname: Bassewitz
authors.affiliation: Gerald F. Schusser, Medizinische Tierklinik, Veterinärmedizinische Fakultät der Universität Leipzig, An den Tierkliniken 11, 04103 Leipzig, E-Mail: schusser@vetmed.uni-leipzig.de.
authors.forename: G F
authors.initials: GF
authors.lastname: Schusser
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D006736:Horses / Q000097:blood*; D007118:Immunoassay / Q000592:standards*; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D008163:Luminescent Measurements / Q000592:standards / Q000662:veterinary*; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D007328:Insulin; D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone
keywords: ACTH; IGF-1; Insulin units; PPID; equine metabolic syndrome