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INULIN, 57 Co‐LABELLED VITAMIN B 12 AND ENDOGENOUS CREATININE CLEARANCES IN THE MEASUREMENT OF GLOMERULAR FILTRATION RATE IN MAN
Author(s) -
JEREMY D.,
MCIVER M.
Publication year - 1966
Publication title -
australasian annals of medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 0571-9283
DOI - 10.1111/imj.1966.15.4.346
Subject(s) - inulin , renal function , chemistry , clearance , filtration fraction , creatinine , plasma clearance , endocrinology , vitamin , medicine , clearance rate , endogeny , chromatography , urology , biochemistry , pharmacokinetics , renal blood flow
SUMMARY In 14 cases, simultaneous clearances of inulin (range 39 to 160 ml. per minute) and endogenous creatinine were measured, and in 11 of these cases, the results were compared with the simultaneous clearance of radioactive ( 57 Co) vitamin B 12 . The clearance of free (dialysable) 57 Co vitamin B 12 correlates closely with inulin clearance (ρ=0·985), and can be used as a measure of glomerular filtration rate. [Clearance of vitamin B 12 (free)=1·07 clearance of inulin—10·9±5·48 (2 S.D.). ] The protein bound (non‐dialysable) fraction of the plasma 57 Co vitamin B 12 varied from patient to patient, and in the same patient at different times (range, 9·6% to 35·7%; mean, 17·7% of total), in spite of presaturation with stable vitamin B 12 . Because of this, the clearance of vitamin B 12 is a valid measure of glomerular filtration rate only when correction is made for plasma protein binding as measured in the individual subject. The correlation between inulin and endogenous creatinine clearance was less precise. [Ratio of clearance of creatinine to clearance inulin=1·20±0·38 (2 S.D.).]