Creatinine Assay Reagents (CRE-CL)
Enzymatic creatinine assay for precise kidney function evaluation.
Ideal for renal diagnostics, dialysis monitoring, and high-throughput clinical workflows.
High-Precision Assay for Reliable Renal Diagnostics and Dialysis Monitoring
Creatinine is a key metabolic waste product used to assess renal function, particularly glomerular filtration efficiency. Measuring creatinine levels in serum is essential for diagnosing kidney disease, evaluating the effectiveness of dialysis, and guiding nephrological treatment decisions.
The CRE-CL creatinine assay from NAGASE uses an enzymatic SOX-POD method that ensures high linearity (0.1–120 mg/dL) and reproducibility. It minimizes interference from coexisting substances and enables accurate, cost-effective quantification of creatinine concentrations in serum.
NAGASE supplies creatinine assay reagents in bulk for diagnostic laboratories and OEM manufacturers.
Applications
CRE-CL is used for evaluating renal function in various diagnostic and monitoring contexts.
- Assessment of glomerular filtration rate (GFR) via serum creatinine levels
- Monitoring renal dialysis effectiveness in chronic kidney disease (CKD)
- Diagnosis of acute and chronic renal disorders
- Detection of urinary tract obstruction or prostatic hypertrophy
- Routine kidney health screening in clinical laboratories
Features
CRE-CL offers high repeatability, broad detection range, and minimal interference for cost-effective creatinine analysis.
- Wide measuring range – High linearity from 0.1 to 120 mg/dL
- Enzymatic SOX-POD method – Reliable performance with precise endpoint detection
- Minimal interference – Low cross-reactivity with coexisting substances
- High repeatability – Consistent results for dependable monitoring
Principle of the Method
In this enzymatic method, the creatinine present in the sample undergoes hydrolysis, catalyzed by creatininase, resulting in the formation of creatine.
Subsequently, the creatine is converted into sarcosine through the action of creatinase.
The sarcosine is then enzymatically decomposed by sarcosine oxidase, leading to the generation of glycine, formaldehyde, and hydrogen peroxide (H2O2).
The produced H2O2 reacts with EHSPT in the presence of peroxidase (POD), giving rise to a chromophore that is measured at 546 nm. The observed increase in absorbance at 546 nm directly correlates with the creatinine content present in the sample, allowing for quantitative determination.
Assay Procedure
Individual instrument applications are available on request.
Assay Reagents, Storage and Stability
Reagent 1: Good’s buffer, Creatinase, Sarcosine oxidase, Ascorbatre oxidase, Catalase, EHSPT
Reagent 2: Good’s buffer, Peroxidase, Creatininase, 4-Aminoantipyrine
Both reagents are liquid, ready to use
Storage: 2-10 °C
Shelf Life: 18 months (before use)
Stability after Opening: at least 2 months at 2-10 °C
Performance Data
The following performance data were obtained on a Hitachi 7170 clinical analyzer.
Method Comparison
Comparison studies were carried out using another similar commercially available method. The following results were obtained.
Sensitivity
The sensitivity was evaluated by reading the change in absorbance for purified water sample and serum samples with known concentrations. The results indicated that CRE-CL showed little or no reagent drift on a zero sample.
Under the reaction condition described, 5.0 mg/dL standard solution gives an ABS of 0.063-0.100.
Linearity
Precision (within-run)
Interfering Substances
Comparison Data – Enzymatic Method vs Jaffe Method
We performed an comparative accuracy test between the enzymatic method and the Jaffe method by analyzing serum samples treated with creatinine deiminase to deactivate creatinine (serum non-specific reactive test).
The enzymatic method showed an average measurement value of 0.032 mg/dL, while the Jaffe method demonstrated an average measurement value of 0.150 mg/dL. These findings indicate that the enzymatic method displays greater specificity in detecting creatinine.
The enzymatic method is a highly specific method for creatinine.
Furthermore, when testing the correlation between the enzymatic method and the Jaffe method, a strong correlation coefficient was observed. However, the results obtained from measuring the same sample showed an average of 1.12 mg/dL, with the enzymatic method, whereas the Jaffe method yielded an average of 1.22 mg/dL, indicating that the Jaffe method produced results approximately 0.1 mg/dL, higher than the enzymatic method. This result aligns with the non-specific reactive test obtained from the “serum non-specific reative test”.
