Table 3 Estimated equilibrium concentrations of main small ions (in mOsm/L H2O) in human interstitial fluid (assumed protein equivalent: − 4.3 mEq/L)
Ion | Estimated equilibrium concentrations: interstitial fluid | Estimated equilibrium concentrations: protein-free fluid | Estimated Gibbs–Donnan factor |
|---|---|---|---|
Na+ | 138.3 | 136.3 | 0.99 |
K+ | 4.1 | 4.0 | 0.99 |
Ca2+ | 1.2 | 1.2 | 0.97 |
Mg2+ | 0.8 | 0.7 | 0.97 |
Cl− | 110.9 | 112.5 | 1.02 |
HCO3− | 24.7 | 25.0 | 1.02 |
Lactate− | 1.2 | 1.3 | 1.02 |
SO42− | 0.5 | 0.5 | 1.03 |
HPO42− | 2.1 | 2.2 | 1.03 |
