Testing Principle
The Biomedia Hcy test kit is based on enzyme cycling method, and the signal amplification by this method enables a much more higher detection sensitivity of the test.
Oxidized Hcy is fist converted into dissociative Hcy. In the forward reaction, Hcy reacts with serine in the presence of cystathionine-β-synthetase (CBS), generating L-Cystathionine. While in the reverse reaction, L-Cystathionine is catalyzed  by cystathionine-β-lyase (CBL), converted back to Hcy, NH3 and pyruvic acid , and are ready for the next round of oxidation reaction. With pyruvic acids and lactic dehydrogenase (LDH), NADH is transformed into NAD+, and the reaction rate is proportional to the concentration of Hcy.

Product Features
1. Linear range
a. Linear correlation coefficient ∣r∣≥0.990
b. Linear range of Hcy level: [3.00, 70.00] mg/L

2. Absorbance of blank ≤ 1.20
3. Sensitivity
The difference of absorbance changing rate(ΔA/min) ≤ 0.02 while testing the specific Cys-C sample of concentration of 12.00 μmol/L.
4. Accuracy
Check the accuracy using the following methods:
(a) Relative deviation is within ±15%.
(b) In contrast experiment, the absolute deviation is within ±20%, and the Linear correlation coefficient is no less than 0.975.
5. Precision
Intra CV% ≤ 5.0%; inter CV% ≤ 10.0%.

Technical Parameters

Packaging Specification
R1: 1×37 ml, R2: 1×10 ml
R1: 1×74 ml, R2: 1×20 ml
R1: 2×37 ml, R2: 2×10 ml
R1: 4×37 ml, R2: 4×10 ml
R1: 2×74 ml, R2: 2×20 ml
R1: 6×37 ml, R2: 6×10 ml

Storage and Period of Validity
Unopened: Store test kits at 2 - 8℃ protected from light. Stable to expiration date printed on individual vials (for 12 months).
Opened: Store test kits at 2 - 8℃ protected from light. Stable for 1 months if kept capped from original container and free from contamination.