Tests for Kidney Disease
Several tests can be done to assess a
patient for kidney disease.
Glomerular Filtration Rate
The glomerular filtration rate is a
measure of the efficiency of kidneys
in filtering blood to excrete metabolic
Typically this is done by
collecting a 24-hour urine sample for
measurement of creatinine clearance.
Impairment of renal function by lupus
nephritis results in reduced levels of
The 24-hour urine
sample can also quantify protein loss.
Performed on a one-time voided
specimen, rather than from a 24
hour collection, this test is useful as
a measure of protein loss and is more
convenient for patients.
Urinalysis can indicate the presence or
extent of renal disease. For example,
proteinuria can be a reliable indicator
of renal disease.
The presence of RBCs,
WBCs, and cellular casts, particularly
red cell casts, in the urine also indicates
Measurement of Serum
Creatinine is a waste product of muscle
metabolism that is excreted by the
Loss of renal function as a
consequence of lupus nephritis causes
increases in serum levels of creatinine.
The concentration of creatinine in the
serum can be used to assess the degree
of renal impairment.
Kidney biopsy can be used to determine
the presence of immune complexes
and the presence, extent, and type
of inflammation in the glomeruli.
Diagnosing the extent and type of
inflammation may help to determine a
treatment program for lupus.
Source: National Institutes of Health, U.S.Dept of Health and Human Services