Originally published in Acta Med. Scand., 116, 561 (1944). 



57. THE RED CORPUSCLE CONTENT OF THE 



CIRCULATING BLOOD DETERMINED BY LABELLING 



THE ERYTHROCYTES WITH RADIO-PHOSPHORUS 



G. Hevesy, K. H. Koster, G. Sorensen, E. Warburg and K. Zerahn 



From the Institute of Theoretical Physics, University, Copenhagen, and the 

 University Clinic of the Rigshospital, Medical Department B, Copenhagen 



The red corpuscle content of the circulating blood is usually calculated 

 from the plasma volume determined by the dye method and the hemato- 

 crit figure. Some time ago (Hahn and Hevesy, 1940; Hevesy and 

 Zerahn, 1942), the red corpuscle content of the rabbit was determined 

 by making use of corpuscles labelled with radiophosphorus. This method 

 was used by us to determine the erythrocyte content of the circulating 

 blood of human subjects. Simultaneously, the corpuscle content was 

 determined by the CO method and, furthermore, in some experiments 

 the plasma volume was determined by the dye method. 



EXPERIMENTAL 



About 25 cm^ blood is taken by venous puncture. After adding heparin 

 and about 1 cm^ plasma^^) of the same subject which contains a minute 

 amount of labelled sodium phosphate showing an activity of about 1 /^ 

 Curie, the blood is placed in a glass bottle with paraffine coated Malls 

 and is gently rotated in a thermostat at 37° for 2 hours. After the lapse 

 of this time, the radio-phosphorus added to the blood is found to be 

 about equally distributed between the corpuscles and the plasma. 

 A minor part of the labelled blood is kept as a standard preparation, 

 while the rest is reintroduced into the human subject. The labelled 

 corpuscles introdued into the circulation get soon mixed with all the 

 circulating corpuscles and, as a result of this mixing, the activity of 

 1 gm corpuscles secured will be much lower than the activity of 1 gm 

 corpuscles introduced. If we reintroduce 1 gm labelled corpuscles 

 containing 1000 activity units while the circulation contains 1000 gm 

 corpuscles, 1 gm corpuscles secured after the mixing, i. e. after the lapse 

 of few minutes, will show an activity of 1 unit. 



^1^ The plasma is obtained by centrifuging blood containing labelled phosphate. 

 36 Hevesy 



