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Axis-Shield Liquid Stable 2-Part Homocysteine Reagent
Over the past few years, routine laboratory Homocysteine (HCY) testing has begun to move away from the mainframe immunoassay analysers onto clinical chemistry platforms.
Axis-Shield has been at the forefront of this change with the Liquid Stable 2-Part Homocysteine Reagent.
The Axis-Shield Liquid Stable 2-Part Homocysteine Reagent offers performance equivalent to immunoassay and also allows:
- Instrument consolidation
- Lower turn-around time
- Improved reagent stability
- Ease of use
The Axis-Shield Liquid Stable 2-Part Homocysteine Assay is a next-generation 2-Reagent assay offering superior performance and stability.
The key features and performance characteristics of the assay are described below:
Intended Use
The Liquid Stable (LS) 2-Part Enzymatic Homocysteine assay is intended for in vitro quantitative determination of total homocysteine in human serum and plasma.
Assay Principle
In the Axis-Shield Liquid Stable 2-Part Homocysteine assay, bound or dimerised homocysteine (oxidised form) is reduced to free homocysteine, which then reacts with serine catalysed by cystathionine beta-synthase (CBS) to form L-cystathionine. Cystathionine in turn is broken down by cystathionine beta-lyase (CBL) to form homocysteine, pyruvate and ammonia. Pyruvate is then converted by lactate dehydrogenase (LDH) to lactate with NADH as coenzyme. The rate of NADH conversion to NAD is directly proportional to the concentration of homocysteine.
Key Features
Method: Enzymatic assay
Sample type: Serum or Serum Separator Tubes and EDTA or heparinized plasma
Sample volume: from 16µL
Lower limit of detection: 0.4 µmol/L
Assay Range: 1-46 µmol/L
Calibrators: 0 & 28 µmol/L (included in kit)
Tests used for calibration: 4 per month (older 3-reagent systems can use up to 50 tests per month for calibrations)
Calibration Curve Stability: up to 30 days
On-board Reagent Stability: up to 30 days
Standardised: To NIST SRM 1955 (Homocysteine Standard Reference Material)
Time to first result: 12 minutes (calibrated Instrument)
Throughput: 36 test per hour (calibrated Instrument)
Reagents: Ready to use with calibrators included
Pack sizes to suit your usage: available in 100, 200 & 1000 test formats.
Assay Performance
Precision:
| Low Control | Medium Control | High Control | |
| Mean µmol/L | 6.3 | 12.3 | 25.5 |
| Within-run CV% | 2.6 | 1.5 | 1.5 |
| Between-run CV% | 1.7 | 1.2 | 1.4 |
| Total CV% | 4.4 | 3.0 | 2.5 |
Correlation to immunoassay:
n = 104
| Bias | 95% CI | |
| Constant | -1.06 | -1.64 to -0.46 |
| Proportional | 1.00 | 0.98 to 1.03 |
Linearity of diluted plasma samples:
If the Homocysteine concentration of a sample exceeds the range of the calibration curve, the sample should be diluted one part specimen with two parts Cal 0µmol/L (provided in the kit) and be reanalysed.
Interferences:
The Axis-Shield Homocysteine Control kit (tri-level, 1.5mL each) is also available for use with this product- FHCY200
Please visit www.axis-shield.com for information.
Homocysteine Testing
To find out more about the different Homocysteine assays available from Axis-Shield, visit www.axis-shield.com
Latest Publications
Homocysteine and Reclassification of Cardiovascular Disease Risk
Associations Between Elevated Homocysteine, Cognitive Impairment, and Reduced White Matter Volume in Healthy Old Adults.
For full details visit the Publications page.
