The Lipid Test Devices work with the Lipid Meter to measure the lipid concentration in whole blood, plasma and serum during professional testing.

The 3-in-1 Lipid Test Device is used to measure the concentrations of Total Cholesterol (TC), High Density Lipoprotein (HDL) and Triglycerides (TG) simultaneously. It is also used to calculate LDL and TC/HDL.

Note: Three separate test devices are also available, which can measure the concentrations of TC, HDL, and TG individually. Lipid measurements are used in the diagnosis and treatment of atherosclerotic coronary artery disease and in the diagnosis of metabolic disorders involving lipids and lipoproteins.

PRINCIPLE

Lipid Test Devices use a timed-endpoint method to measure the Total Cholesterol (TC)/High Density Lipoprotein (HDL)/Triglycerides (TG) concentrations in whole blood, serum or plasma. The concentration of Low Density Lipoprotein (LDL) is calculated by the values of TC, TG and HDL.

The system monitors the change in absorbance at 635 nm at a fixed-time interval. The change in absorbance is directly proportional to the concentration of lipid in the specimen.

TC: In the reaction, cholesterol esterase hydrolyzes cholesterol esters to free cholesterol and fatty acids The free cholesterol is oxidized to cholesten-3-one and hydrogen peroxide by cholesterol oxidase. Peroxidase catalyzes the reaction of hydrogen peroxide with 4-aminoantipyrine and phenol to produce a colored quinoneimine product.

HDL: The dextran sulphate/Mg2+ on the test device precipitates the chylomicrons, VLDL and LDL, leaving HDL in the specimen. The cholesterol concentration of this HDL is then determined enzymatically, the same as TC.

TG: Triglycerides in the specimen are hydrolyzed to glycerol and free fatty acids by the action of lipase. A sequence of three coupled enzymatic steps using glycerol kinase (GK), glycerophosphate oxidase (GPO), and horseradish peroxidase (POD) causes the oxidative coupling of 4-aminoantipyrine to form a blue dye.

LDL: When the concentration of TG in the specimen is equal to or lower than 400mg/dL, LDL concentration can be calculated by the meter with the following equation:

LDL = TC – HDL – TG/2.2 (mmol/L);LDL = TC- HDL -TG/5 (mg/dL)

Calculated LDL is an estimation of LDL.