title: A multicenter nationwide reference intervals study for common biochemical analytes in Turkey using Abbott analyzers.
abstract: BACKGROUND
  A nationwide multicenter study was organized to establish reference intervals (RIs) in the Turkish population for 25 commonly tested biochemical analytes and to explore sources of variation in reference values, including regionality.
  
  
  METHODS
  Blood samples were collected nationwide in 28 laboratories from the seven regions (≥400 samples/region, 3066 in all). The sera were collectively analyzed in Uludag University in Bursa using Abbott reagents and analyzer. Reference materials were used for standardization of test results. After secondary exclusion using the latent abnormal values exclusion method, RIs were derived by a parametric method employing the modified Box-Cox formula and compared with the RIs by the non-parametric method. Three-level nested ANOVA was used to evaluate variations among sexes, ages and regions. Associations between test results and age, body mass index (BMI) and region were determined by multiple regression analysis (MRA).
  
  
  RESULTS
  By ANOVA, differences of reference values among seven regions were significant in none of the 25 analytes. Significant sex-related and age-related differences were observed for 10 and seven analytes, respectively. MRA revealed BMI-related changes in results for uric acid, glucose, triglycerides, high-density lipoprotein (HDL)-cholesterol, alanine aminotransferase, and γ-glutamyltransferase. Their RIs were thus derived by applying stricter criteria excluding individuals with BMI >28 kg/m2. Ranges of RIs by non-parametric method were wider than those by parametric method especially for those analytes affected by BMI.
  
  
  CONCLUSIONS
  With the lack of regional differences and the well-standardized status of test results, the RIs derived from this nationwide study can be used for the entire Turkish population.
authors.forename: Yesim
authors.initials: Y
authors.lastname: Ozarda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ichihara
authors.forename: Diler
authors.initials: D
authors.lastname: Aslan
authors.forename: Hulya
authors.initials: H
authors.lastname: Aybek
authors.forename: Zeki
authors.initials: Z
authors.lastname: Ari
authors.forename: Fatma
authors.initials: F
authors.lastname: Taneli
authors.forename: Canan
authors.initials: C
authors.lastname: Coker
authors.forename: Pinar
authors.initials: P
authors.lastname: Akan
authors.forename: Ali Riza
authors.initials: AR
authors.lastname: Sisman
authors.forename: Onur
authors.initials: O
authors.lastname: Bahceci
authors.forename: Nurzen
authors.initials: N
authors.lastname: Sezgin
authors.forename: Meltem
authors.initials: M
authors.lastname: Demir
authors.forename: Gultekin
authors.initials: G
authors.lastname: Yucel
authors.forename: Halide
authors.initials: H
authors.lastname: Akbas
authors.forename: Sebahat
authors.initials: S
authors.lastname: Ozdem
authors.forename: Gurbuz
authors.initials: G
authors.lastname: Polat
authors.forename: Ayse Binnur
authors.initials: AB
authors.lastname: Erbagci
authors.forename: Mustafa
authors.initials: M
authors.lastname: Orkmez
authors.forename: Nuriye
authors.initials: N
authors.lastname: Mete
authors.forename: Osman
authors.initials: O
authors.lastname: Evliyaoglu
authors.forename: Aysel
authors.initials: A
authors.lastname: Kiyici
authors.forename: Husamettin
authors.initials: H
authors.lastname: Vatansev
authors.forename: Bahadir
authors.initials: B
authors.lastname: Ozturk
authors.forename: Dogan
authors.initials: D
authors.lastname: Yucel
authors.forename: Damla
authors.initials: D
authors.lastname: Kayaalp
authors.forename: Kubra
authors.initials: K
authors.lastname: Dogan
authors.forename: Asli
authors.initials: A
authors.lastname: Pinar
authors.forename: Mehmet
authors.initials: M
authors.lastname: Gurbilek
authors.forename: Cigdem Damla
authors.initials: CD
authors.lastname: Cetinkaya
authors.forename: Okhan
authors.initials: O
authors.lastname: Akin
authors.forename: Muhittin
authors.initials: M
authors.lastname: Serdar
authors.forename: Ismail
authors.initials: I
authors.lastname: Kurt
authors.forename: Selda
authors.initials: S
authors.lastname: Erdinc
authors.forename: Ozgur
authors.initials: O
authors.lastname: Kadicesme
authors.forename: Necip
authors.initials: N
authors.lastname: Ilhan
authors.forename: Dilek Sadak
authors.initials: DS
authors.lastname: Atali
authors.forename: Ebubekir
authors.initials: E
authors.lastname: Bakan
authors.forename: Harun
authors.initials: H
authors.lastname: Polat
authors.forename: Tevfik
authors.initials: T
authors.lastname: Noyan
authors.forename: Murat
authors.initials: M
authors.lastname: Can
authors.forename: Abdulkerim
authors.initials: A
authors.lastname: Bedir
authors.forename: Ali
authors.initials: A
authors.lastname: Okuyucu
authors.forename: Orhan
authors.initials: O
authors.lastname: Deger
authors.forename: Suret
authors.initials: S
authors.lastname: Agac
authors.forename: Evin
authors.initials: E
authors.lastname: Ademoglu
authors.forename: Ayşem
authors.initials: A
authors.lastname: Kaya
authors.forename: Turkan
authors.initials: T
authors.lastname: Nogay
authors.forename: Nezaket
authors.initials: N
authors.lastname: Eren
authors.forename: Melahat
authors.initials: M
authors.lastname: Dirican
authors.forename: GulOzlem
authors.initials: G
authors.lastname: Tuncer
authors.forename: Mehmet
authors.initials: M
authors.lastname: Aykus
authors.forename: Yeliz
authors.initials: Y
authors.lastname: Gunes
authors.forename: Sevda Unalli
authors.initials: SU
authors.lastname: Ozmen
authors.forename: Reo
authors.initials: R
authors.lastname: Kawano
authors.forename: Sehavet
authors.initials: S
authors.lastname: Tezcan
authors.forename: Ozlem
authors.initials: O
authors.lastname: Demirpence
authors.forename: Elif
authors.initials: E
authors.lastname: Degirmen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001798:Blood Proteins / Q000032:analysis* / Q000592:standards; D015992:Body Mass Index; D019963:Clinical Chemistry Tests / Q000592:standards; D005260:Female; D006801:Humans; D007287:Inorganic Chemicals / Q000097:blood* / Q000592:standards; D008055:Lipids / Q000097:blood* / Q000592:standards; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009930:Organic Chemicals / Q000097:blood* / Q000592:standards; D012016:Reference Values; D014421:Turkey
chemical_list: D001798:Blood Proteins; D007287:Inorganic Chemicals; D008055:Lipids; D009930:Organic Chemicals