Gabel J C, Scott R L, Adair T H, Drake R E, Traber D L
Am J Physiol. 1980 Dec;239(6):H810-2. doi: 10.1152/ajpheart.1980.239.6.H810.
Several equations to calculate plasma oncotic pressure (pi) from the total protein concentration (C) have been previously described. These equations were derived empirically from samples with a wide range of C obtained by diluting or concentrating normal plasma samples. To test these equations over a range of naturally occurring C, we measured C and pi of plasma samples from 40 dogs. C ranged from 5.3 to 8.7 g/dl and averaged 6.5 +/- 0.1 (mean +/- SE) and pi averaged 17.9 +/- 0.3 mmHg. The regression equation was pi = 78.14 + 1.67 C (r = 0.74). pi increased with C much less than predicted with the commonly used equations. The albumin-to-globulin concentration ratios (A/G), determined in 27 of the dogs, decreased with increasing C (A/G = 1.56-0.128 C, r = 0.62). The lower A/G at the higher C's could cause the lower than predicted increase in pi with C, because the equations were developed from data in which A/G was constant.
此前已描述了几个根据总蛋白浓度（C）计算血浆胶体渗透压（π）的公式。这些公式是通过对正常血浆样本进行稀释或浓缩后，从一系列测得的C值的样本中凭经验推导出来的。为了在自然存在的C值范围内检验这些公式，我们测定了40只犬血浆样本的C值和π值。C值范围为5.3至8.7g/dl，平均为6.5±0.1（均值±标准误），π值平均为17.9±0.3mmHg。回归方程为π = 78.14 + 1.67C（r = 0.74）。π随C值的增加幅度远小于常用公式的预测值。在27只犬中测定的白蛋白与球蛋白浓度比（A/G）随C值增加而降低（A/G = 1.56 - 0.128C，r = 0.62）。在较高C值时较低的A/G可能导致π随C值增加的幅度低于预测值，因为这些公式是根据A/G恒定的数据推导出来的。
