title: Establishing Reference Intervals of Aspartate Aminotransferase-to-Platelet Ratio Index for Apparently Healthy Elderly.
abstract: BACKGROUND
  Aspartate aminotransferase (AST) to platelet ratio index (APRI) serves as a parameter in evaluating liver fibrosis in current clinical practice. However, reference standard (reference intervals, RIs) or baseline levels of APRI have not been previously reported. The purpose of this paper is to establish the reference intervals of APRI in apparently healthy elderly people from the region of Shuyang, China.
  
  
  METHODS
  Blood specimens were collected from local elderly residents (selected 51,263 elderly Han Shuyang Chinese from 65 to 97 years old, 32.97% males and 67.03% females) by standard procedures. Complete blood counts were determined by Sysmex XE-2100 analyzer and the AST values were measured by a TBA2000FR automatic biochemical analyzer (Toshiba Co., Ltd., Japan). The 95% reference intervals were calculated by using the non-parametric method according to the document: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline-Third Edition (C28-A3) of CLSI.
  
  
  RESULTS
  RIs established for healthy elderly include: 0.1398-0.6266 for males and 0.1282-0.5798 for females (0.1284-0.5086 for 65-74 years old; 0.1209-0.5704 for > or = 75 years old). Ris of APRI for elderly males were higher than those of females, and values of APRI increased with increasing age for females.
  
  
  CONCLUSIONS
  We established scientific and reasonable RIs of APRI for the healthy elderly in our region.
authors.forename: Guo-Ming
authors.initials: GM
authors.lastname: Zhang
authors.forename: Xu-Xiao
authors.initials: XX
authors.lastname: Guo
authors.forename: Bao-Lin
authors.initials: BL
authors.lastname: Zhu
authors.forename: Gao-Ming
authors.initials: GM
authors.lastname: Zhang
authors.forename: Shu-Mei
authors.initials: SM
authors.lastname: Bai
authors.forename: Hong-Jian
authors.initials: HJ
authors.lastname: Wang
authors.forename: Xia-Bo
authors.initials: XB
authors.lastname: Ma
authors.forename: Ye-Ting
authors.initials: YT
authors.lastname: Zhou
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002681:China; D004796:Clinical Enzyme Tests / Q000592:standards*; D005260:Female; D015577:Geriatric Assessment; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D010976:Platelet Count / Q000592:standards*; D011237:Predictive Value of Tests; D012016:Reference Values; D012737:Sex Factors
chemical_list: D015415:Biomarkers; D001219:Aspartate Aminotransferases