[Effects of erythrocytes on electrometric pH measurements (author's transl)].

Erythrocyte interference in electrometric readings has been demonstrated and quantified in pH measurements. The presence of erythrocytes introduces a negative component into the final result of the electrometric reading, proportional to the hematocrit. There is indirect evidence that this does not correspond to a true proton concentration change, but to the presence of the erythrocytes per se. The authors suggest the use of a correcting factor (0.01 pH unit per tens of hematocrit units) to obtain the real pH from a pH value measured on whole blood: however the use of this correcting factor should be restricted to the type of equipment described.