title: Normative reference values for lung transfer factor in Isfahan, Iran.
abstract: OBJECTIVE
  Transfer factor or carbon monoxide diffusing capacity (DL(CO)) is a particularly valuable test of the appropriateness of gas exchange across the alveolocapillary membrane. The purpose of this study is to derive predictive equations for DL(CO) and its derivative volume-corrected DL(CO) (DL(CO)/VA) measured by single-breath method in a large non-smoking population sample in Isfahan.
  
  
  METHODS
  We evaluated 1429 randomly selected subjects (732 men, aged 5-85 years). Gender-specific linear prediction equations were developed by multiple regression analysis; with measured DL(CO), and DL(CO)/VA values (mmol/min/kPa), as dependent variables regressed against age (A), height (H) and body surface area (BSA).
  
  
  RESULTS
  For both genders, age had negative effects on DL(CO), while height had a positive effect on DL(CO) and DL(CO)/VA (P < 0.01). The prediction equations for DL(CO) and DL(CO)/VA are: '0.152 x height - 0.056 x age - 11.595' and '-0.12 x age + 2.467', for men and: '-0.035 x age - 0.133 x height - 10.707' and '-0.012 x age - 0.02 x height + 2.755', for women, respectively.
  
  
  CONCLUSIONS
  Our results therefore provide an original frame of reference for either DL(CO) or DL(CO)/VA in Iranian population, obtained from a standardized single-breath technique.
authors.affiliation: Isfahan University of Medical Sciences, Isfahan, Iran. amra@med.mui.ac.ir
authors.forename: Babak
authors.initials: B
authors.lastname: Amra
authors.forename: Mehrnaz
authors.initials: M
authors.lastname: Asadi
authors.forename: Hassan
authors.initials: H
authors.lastname: Salehi
authors.forename: Ahmad R
authors.initials: AR
authors.lastname: Zamani
authors.forename: Mohammad
authors.initials: M
authors.lastname: Golshan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D002248:Carbon Monoxide / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007492:Iran; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011653:Pulmonary Diffusing Capacity; D012016:Reference Values; D012044:Regression Analysis; D012129:Respiratory Function Tests
chemical_list: D002248:Carbon Monoxide