Axis-Shield are the global patent holders for Homocysteine immunoassays. First launched in 1995, the Axis-Shield assay is still the only EIA method available for labs without access to automated instruments.
Each kit comes complete with all required reagents and calibrators. A control pack is also available from Axis-Shield.
Axis Homocysteine EIA Reagent kit (96 Well) - FHCY100
Axis-Shield Homocysteine Control Kit (3 x 1.5mL) - FHCY200
Intended Use:
The Axis® Homocysteine Enzyme Immunoassay (EIA) is intended for the quantitative determination of total L-homocysteine in human serum or plasma. The device can assist in the diagnosis and treatment of patients suspected of having hyperhomocysteinemia and homocystinuria.
Assay Principle:
The Axis-Shield Homocysteine Enzyme Immunoassay (EIA) is an enzyme immunoassay for the determination of homocysteine (Hcy) in serum or plasma. Protein-bound Hcy is reduced to free Hcy and enzymatically converted to S-adenosyl-L-homocysteine (SAH) in a separate procedure prior to the immunoassay.
Measuring Range:
The calibrator range is from 2 to 50 µmol/L.
Assay Precision:
Precision of the Homocysteine EIA assay was evaluated according to CLSI Protocol EP5. Three levels of controls were assayed for 20 days with 4 replicates per run at each level. Precision data are summarised in Table 1.
Table 1: Precision
| Samples | Average µmol/L | Within Run Precision | Total Precision | ||
| Control Low | 6.1 | 8% | 10% | ||
| Control Medium | 10.5 | 7% | 9% | ||
| Control High | 20.6 | 8% | 10% |
Limit of Quantification:
The quantification limit (CV < 20%) is 1.0 µmol/L.
Linearity of diluted plasma samples:
If the homocysteine concentration of a sample exceeds the range of the calibration curve, the sample should be diluted with Reagent A and reanalysed.
The linearity was evaluated by diluting four high patient samples with varying amounts of Reagent A as diluent.
Linear regression analysis gave:
Slope: 0.98
Intercept: -0.4µmol/L
Correlation coefficient: r2: 0.99
Method Comparison:
The Axis® Homocysteine Enzyme Immunoassay (EIA) was compared to the University of Bergen HPLC method. A comparison of 164 patient samples ranging from 3-37µmol/L homocysteine gave the linear regression shown below.
Slope: 0.94
Intercept: -0.09 µmol/L
Correlation coefficient: (r2): 0.94
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A pioneering organisation focused on the development and manufacturing of important and innovative in vitro diagnostic tests for use in clinical laboratories and at the point of care.
Axis-Shield's award winning point-of-care test system is designed for maximum simplicity coupled with laboratory accuracy and reliability for a number of key markers important for improved patient management.