Multicentre physiological reference values for the concentration of creatininium in plasma and diagnostic specificity of glomerular filtration rate estimated with the MDRD equation.
BACKGROUND
The National Kidney Disease Education Program recommends that clinical laboratories, when asked for an estimation of glomerular filtration rate in a patient by means of the "four-variable" Modification of Diet in Renal Disease (MDRD) Study equation, also provide the measurement result for creatininium concentration in plasma and the appropriate reference interval. On the other hand, clinical laboratories seeking accreditation for compliance with ISO 15189:2003 need to demonstrate that the physiological reference intervals communicated to all users of laboratory services are appropriate for the patient population served, and for their measurement systems.


METHODS
Ten clinical laboratories in different regions of Spain collaborated in identifying reference individuals and producing reference values for the concentration of creatininium in plasma using RD/Hitachi Modular Analytics analysers, and for the volume rate of glomerular filtrate in kidneys (glomerular filtration rate), estimated with the "four-variable" MDRD Study equation. All the logistic work was carried out in co-operation with the supplier of the reagents and analysers (Roche Diagnostics España, S.L., Sant Cugat del Vallès, Catalonia, Spain). Using all the reference values obtained by each laboratory, multicentre reference limits were estimated non-parametrically.


CONCLUSIONS
Reference intervals estimated in this study for concentrations of plasma creatininium are 52-85 micromol/L for women and 64-106 micromol/L for men. The diagnostic specificity of the estimated glomerular filtration rate is 99.2% when applied to healthy persons to screen for chronic kidney disease.
Fuentes-Arderiu
Xavier
X
Laboratori Clínic, IDIBELL-Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Catalonia, Spain. xfa@csub.scs.es
Alvarez-Funes
Virtudes
V
Coca-Fábregas
Lluís
L
Cruz-Placer
Marta
M
Díaz-Fernández
Julián
J
Herrero-Bernal
Pilar
P
García-Caballero
Francisca
F
del Mar Larrea-Ortiz-Quintán
María
M
La-Torre-Marcellán
Pedro
P
Mar-Medina
Carmen
C
Victoria Rodríguez-Hernández
María
M
Juvé-Cuxart
Santiago
S
D002908:Chronic Disease; D003404:Creatinine / Q000097:blood* / Q000592:standards; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis*; D012016:Reference Values; D012680:Sensitivity and Specificity
D003404:Creatinine