Clinical significance of optimal red cell mass and plasma volume estimation methods.
BACKGROUND
The aim of this study was to present and compare the results of proposed methods for optimal red cell mass and plasma volume (RCM&PV) estimation, and their influence on the interpretation of obtained results.


METHODS
In 120/280 patients with polycythaemia rubra vera, subjected to RCM&PV determination with autologous erythrocytes in vitro labelled with 51Cr-sodium chromate, optimal volumes were determined using: 1. traditional ml/kg of: --the real body weight method (ml/kg RBW); --the optimal body weight method (ml/kg OBW). 2. the body weight, height, and sex based method (Retzlaff's tables), 3. the method recommended by the International Council for Standardization in Haematology (ICSH), based on body surface area.


RESULTS
Different interpretation of the same results of 120 RCM&PV measurements was registered in 48/120 patients (40%). The greatest disagreement existed between ml/kg RBW and ml/kg OBW methods (in 39/120 subjects, 32.5%). In underweight patients the ml/kg RBW method, and in overweight patients the ml/kg OBW method, offered better agreement with ICSH&Retzlaff's methods. The ml/kg RBW method disagreed with ICSH&Retzlaff's methods and ml/kg OBW in 25% and 19.2% of patients respectively. ICSH and Retzlaff's methods disagreed in 10/120 patients (8.3%). The ICSH method yielded significantly lower optimal volumes than Retzlaff's.


CONCLUSIONS
Three methods for optimal RCM&PV estimation lead to different interpretations of the same results of RCM&PV measurements with 51Cr-erythrocytes in 40% of patients. Two ml/kg body weight methods show greater disagreement in comparison with ICSH and Retzlaff's methods, which differ significantly. The ICSH method yields lower optimal values compared to Retzlaff's.
Nuclear Medicine Institute, Clinical Centre of Serbia, Belgrade, Serbia and Montenegro. t.t.mila@sezamro.yu
Mila V
MV
Todorović-Tirnanić
Smiljana V
SV
Pavlović
Vladimir B
VB
Obradović
Ivo V
IV
Elezović
Dragomir Z
DZ
Marisavljević
Peda S
PS
Miljić
Rajko A
RA
Milosević
Andrija D
AD
Bogdanović
Vladimir B
VB
Bosnjaković
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001811:Blood Volume Determination / Q000379:methods* / Q000592:standards; D001823:Body Composition; D002840:Chromates / Q000097:blood; D004912:Erythrocytes / Q000000981:diagnostic imaging*; D017408:Guidelines as Topic; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods* / Q000592:standards; D007553:Isotope Labeling / Q000379:methods; D008875:Middle Aged; D010949:Plasma / Q000000981:diagnostic imaging*; D010953:Plasma Volume; D011087:Polycythemia Vera / Q000097:blood* / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000097:blood; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017670:Sodium Compounds / Q000097:blood
D002840:Chromates; D019275:Radiopharmaceuticals; D017670:Sodium Compounds; C028982:sodium chromate(VI)