title: [Survey and analysis on sources of reference intervals and distribution of medical decision levels in NT-proBNP, BNP and homocysteine].
abstract: OBJECTIVE
  To analyze the sources of reference intervals and distribution of medical decision levels in NT-proBNP, BNP and homocysteine (Hcy) based on the feedback of laboratories which participated in the 2014 External Quality Assessment (EQA) program in China.
  
  
  METHODS
  Information of reference intervals and medical decision levels was collected from the 2014 EQA programs in NT-proBNP, BNP and Hcy.All the abnormal values and errors were eliminated.Data were analyzed by SPSS 13.0 and Microsoft Excel 2007 in terms of referring to sources of reference intervals and distribution of medical decision levels.Values were further grouped based on instrument system for NT-proBNP and BNP, reagent manufacturers for Hcy.
  
  
  RESULTS
  There were 330, 119 and 339 laboratories submitting the data on the reference intervals of NT-proBNP, BNP and Hcy. Only 133, 54 and 102 laboratories provided information about medical decision levels.Most reference sources were derived from reagent manufactures (NT-proBNP 76.97%(254/330), BNP 89.08%(106/119), Hcy 83.19%(282/339)). Approximately, 36.53%(122/334), 45.38%(54/119) and 47.95%(164/342) of the laboratories validated the reference intervals of NT-proBNP, BNP and Hcy.According to the surveys, the mean and median values were not close to each other (NT-proBNP 507.99 ng/L and 300.00 ng/L, BNP 342.72 ng/L and 100.00 ng/L, Hcy 17.34 µmol/L and 15.00 µmol/L). Variation of P2.5 and P97.5 was as follows: (NT-proBNP 125.00-1 800.00 ng/L, BNP 87.50-4562.50 ng/L, Hcy 4.15-50.00 µmol/L). The ranges were NT-proBNP 60.00-7 000.00 ng/L, and BNP 80.00-7 000.00 ng/L, and Hcy 1.5-52.00 µmol/L.P values of rank sum test for NT-proBNP, BNP and Hcy were 0.449, 0.208 and 0.754.
  
  
  CONCLUSIONS
  Medical decision levels of NT-proBNP, Hcy and BNP showed large variation among laboratories and the sources of reference interval were not unified.Thus, urgent efforts should be made to establish appropriate reference intervals for Chinese people and promote harmonization and standardization of reference intervals and medical decision levels on BNP, NT-proBNP and Hcy.
authors.affiliation: National Center for Clinical Laboratory, Beijing Hospital, Beijing 100730, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
authors.affiliation: National Center for Clinical Laboratory, Beijing Hospital, Beijing 100730, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: National Center for Clinical Laboratory, Beijing Hospital, Beijing 100730, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhong
authors.affiliation: National Center for Clinical Laboratory, Beijing Hospital, Beijing 100730, China.
authors.forename: Falin
authors.initials: F
authors.lastname: He
authors.affiliation: National Center for Clinical Laboratory, Beijing Hospital, Beijing 100730, China; Email: zgwang@nccl.org.cn.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Wang
mesh_terms: D044466:Asian People; D002681:China; D000066491:Clinical Decision-Making; D006710:Homocysteine; D006801:Humans; D020097:Natriuretic Peptide, Brain; D010446:Peptide Fragments; D012016:Reference Values; D011795:Surveys and Questionnaires
chemical_list: D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D006710:Homocysteine; D020097:Natriuretic Peptide, Brain