Dear David Newman,
We have run serum Cystatin C as a routine analysis since 1995. Currenly we
run it on a Hitachi instrument. Evidence indicates that serum cystatin C is
a better marker for GFR than serum creatinine, particularly for the
identification of an initial small decrease in GFR. The most efficient use
of this knowledge in clinical practice requires that quantitative methods
of good precision and undisturbed by sample turbidity are used. At least
some of the presently available particle-enhanced immunoturbidimetric
methods seem to fulfil the first criterion of acceptable precision but
non-turbid fasting samples should preferably be used until new methods
undisturbed by turbidity are developed. In situations when the GFR has been
determined by accurate invasive clearance methods, either serum cystatin C
or creatinine might be used to follow changes in GFR. However, as long as
the precision of the methods for creatinine determination are higher than
that of the methods for cystatin C determination, there is presently no
valid reasons to use serum cystatin C for this purpose, particularly since
creatinine determinations generally are cheaper than cystatin C
determinations.
If you would like to discuss the method further, please contact Prof.
Anders Grubb (E-mail: [log in to unmask]) who has most experience
of the method in our laboratory.
with best regards,
Ulf Ekström
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Ulf Ekström, MD, Ph. D.
Institute of Laboratory Medicine
Dept. of Clinical Chemistry
Lund University Hospital
S-221 85 Lund, Sweden
Phone:+46-46-173460, Fax: +46-46-13 00 64
E-mail: [log in to unmask]
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