Normative reference values for lung transfer factor in Isfahan, Iran

Respirology. 2006 Jul;11(4):477-81. doi: 10.1111/j.1440-1843.2006.00876.x.


Objectives and background: 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.

Methodology: 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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Body Height
  • Carbon Monoxide / physiology*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Iran
  • Male
  • Middle Aged
  • Oxygen Consumption
  • Pulmonary Diffusing Capacity*
  • Reference Values
  • Regression Analysis
  • Respiratory Function Tests


  • Carbon Monoxide