Journal of Research in Medical Sciences1735-199511620061228Mathematical model for determination of colloid osmotic pressure: The role of albumin-globulin ratio364369ENMehdiNematbakhshPhysiology Research Center, Isfahan University of Medical Sciences. nematbakhsh@mui.ac.irAliMoradiMajidKhazaeiSomaiehJafari2007012320070123BACKGROUND: Colloid Osmotic Pressure (COP) is an important factor in the fluid balance of body compartments. COP is related to Total Protein (TP) concentration and Albumin: Globulin Ratio (A/G). The A/G was not included in pervious empirical models, and therefore the main objective of this study was to develop a mathematical model to determine the COP in terms of TP concentration and A/G. METHODS: Sera with different A/G were prepared in-vitro, and COP was measured directly using colloid osmometer. The relationship between COP, TP concentration and A/G were determined mathematically. The validity of developed empirical models was confirmed by statistical comparison between measured and calculated COP in 122 serum samples obtained from hospitalized patients and healthy individuals. RESULTS: By non-linear regression, the following relationships were found between COP, TP concentration and A/G. All coefficients were statistically significant (p