N Latex Cystatin C AssayAssay for Early Detection of Decline in Renal Function

N Latex Cystatin C Assay
The IFCC-standardized assay enables earlier detection of renal function decline.

Renal disease often progresses undetected, because kidney impairment does not cause pain. This is why chronic kidney disease is not diagnosed until patients show symptoms of an advanced stage of the disease. In the early stages of disease, laboratory testing is the most efficient and sensitive way to detect reduction in renal function.¹

Cystatin C shows increased sensitivity to renal dysfunction compared to serum creatinine, especially in the early stage of kidney disease characterized by a mild reduction in glomerular filtration rate.

The N Latex Cystatin C Assay:

Is suitable for both serum and plasma specimens
Has low imprecision (total CV <5%)
Runs on the BN™ II System and BN ProSpec® System

Features & Benefits

Cystatin C is a nonglycated, low-molecular-weight (13 kDa) protein that is synthesized by all nucleated cells. It is produced at a constant rate regulated by a housekeeping gene.² Cystatin C is freely filtered by the glomerulus, and there is no tubular secretion or any extrarenal elimination. In addition, cystatin C is not affected by muscle mass, diet, gender, or inflammation.

The relevance of determining cystatin C for diagnosis in CKD is included in the international KDIGO (Kidney Disease Improving Global Outcomes) guidelines.³

No tubular secretion; sensitive in the creatinine-blind range²

Higher sensitivity in early disease

Independent of age, sex, and muscle mass²

Constant relationship between cystatin C and glomerular filtration rate (GFR) at 1 year of age and older
Single reference range: 0.49 – 1.19 mg/L in children and adults
Sensitive detection of declining GFR with aging
Reliable in patients with spina bifida, paralysis, amputations, etc.

High correlation to GFR reference methods²; high correlation to GFR decline

High reliability and accuracy

No analytical interferences known

If you are interested in adding the N Latex Cystatin C Assay to your BN II or BN ProSpec system menu, please contact the Inside Sales Department at (800) 242-3233, option 3.

Technical Details

Assay characteristics

Assay principle	Latex-enhanced immunonephelometry
Sample type	Serum, lithium-heparinized plasma
Sample Volume	30 uL
Time to First Result	6 minutes
Initial Sample Dilution	1:100 (auto-dilution)
Standard Dilutions	1:20 to 1:640 (auto-dilution)
Initial measuring range	0.27 – 9.4 mg/L
Reference range	0.49 – 1.19 mg/L
Antigen Excess Security	No hook effect up to 42.91 mg/L
Reagent Onboard Stability	5 days at 8 hours each (BN II System) 4 weeks (BN ProSpec System)
Standardization	ERM-DA471/IFCC

If you are interested in adding the N Latex Cystatin C Assay to your BN II or BN ProSpec system menu, please contact the Inside Sales Department at (800) 242-3233, option 3.

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1. Levey AS, Coresh J, Balk E, et al. National Kidney Foundation Practice Guidelines for Chronic Kidney Disease: Evaluation, classification, and stratification. Ann Intern Med. 2003;139:137-47.

Newman DJ. Cystatin C. Ann Clin Biochem. 2002;39:89-104.

Woitas RP, Stoffel-Wagner B, Flommersfeld S, et al. Correlation of serum concentrations of cystatin C and creatinine to inulin clearance in liver cirrhosis. Clin Chem. 2000;46:712–15