Clinical Info
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Aids in the assessment of glomerular filtration rate in patients for whom serum creatinine may be misleading, such as the very obese, elderly, or malnourished patients.
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Result Interpretation
CYSTATIN C
Males:
0 days-22 years: no reference values established
23-29 years: 0.60-1.03 mg/L
30-39 years: 0.64-1.12 mg/L
40-49 years: 0.68-1.22 mg/L
50-59 years: 0.72-1.32 mg/L
60-69 years: 0.77-1.42 mg/L
70-79 years: 0.82-1.52 mg/L
>79 years: no reference values established
Females:
0 days-22 years: no reference values established
23-29 years: 0.57-0.90 mg/L
30-39 years: 0.59-0.98 mg/L
40-49 years: 0.62-1.07 mg/L
50-59 years: 0.64-1.17 mg/L
60-69 years: 0.66-1.26 mg/L
70-80 years: 0.68-1.36 mg/L
81-86 years: 0.70-1.45 mg/L
>86 years: no reference values established
eGFR
>60 mL/min/BSA
eGFR will not be calculated for patients under 18 years.
Interpretation:
Cystatin C:
Cystatin C inversely correlates with the glomerular filtration
rate (GFR), that is elevated levels of cystatin C indicate
decreased GFR. Cystatin C may provide more accurate assessment of
GFR for very obese, elderly, or malnourished patients than
creatinine. Cystatin C equation does not require patient ethnic
data, and can be used for those patients with this information
unavailable.
Due to immaturity of renal function, cystatin C levels are
higher in neonates <3 months of age.(2)
Estimated Glomerular Filtration Rate (eGFR):
Chronic kidney disease (CKD) is defined as the presence of:
persistent and usually progressive reduction in GFR (GFR <60
mL/min/1.73 m[2]) and/or albuminuria (>30 mg of urinary albumin
per gram of urinary creatinine), regardless of GFR.
According to the National Kidney Foundation Kidney Disease
Outcome Quality Initiative (K/DOQI) classification, among patients
with CKD, irrespective of diagnosis, the stage of disease should be
assigned based on the level of kidney function:
Stage
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Description
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GFR mL/min/BSA
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1
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Kidney damage with normal or increased GFR
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90
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2
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Kidney damage with mild decrease in GFR
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60-89
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3
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Moderate decrease in GFR
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30-59
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4
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Severe decrease in GFR
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15-29
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5
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Kidney failure
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<15 (or dialysis)
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