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Test ID: HDL
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HDL
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Useful For
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To help determine the risk of developing heart disease and to monitor lipid-lowering lifestyle changes and drug therapies.
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Method name and description
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| Homogeneous enzymatic colorimetric assay |
Homogeneous enzymatic colorimetric assay performed on the Roche cobas c-systems. In the presence of magnesium ions, dextran sulfate selectively forms water‑soluble complexes with LDL, VLDL and chylomicrons which are resistant to PEG‑modified enzymes. The cholesterol concentration of HDL‑cholesterol is determined enzymatically by cholesterol esterase and cholesterol oxidase coupled with PEG to the amino groups (approx. 40 %). Cholesterol esters are broken down quantitatively into free cholesterol and fatty acids by cholesterol esterase. In the presence of oxygen, cholesterol is oxidized by cholesterol oxidase to Δ4‑cholestenone and hydrogen peroxide. In the presence of peroxidase, the hydrogen peroxide generated reacts with 4‑amino‑antipyrine and HSDA to form a purple‑blue dye. The color intensity of this dye is directly proportional to the cholesterol concentration and is measured photometrically.
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Clinical information
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High density lipoproteins (HDL) are responsible for the reverse transport of cholesterol from the peripheral cells to the liver. Monitoring of HDL‑cholesterol in serum is of clinical importance since an inverse correlation exists between serum HDL‑cholesterol concentrations and the risk of atherosclerotic disease. Elevated HDL‑cholesterol concentrations are protective against coronary heart disease, while reduced HDL‑cholesterol concentrations, particularly in conjunction with elevated triglycerides, increase the cardiovascular risk.Strategies have emerged to increase the level of HDL-cholesterol to treat cardiovascular disease.
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Aliases
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| High Density Lipoproteins-Cholesterol, HDL |
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum, Plasma
Minimum volume of sample: 1 mL
Serum: Plain tube (red or yellow top)
Plasma: Li‑heparin tube
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Collection instructions / Special Precautions / Timing of collection
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| Fasting and non‑fasting samples can be used |
Collect blood by standard venipuncture techniques as per specimen requirements. When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
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Storage and transport instructions
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Storage: 7 days at 2 – 8°C
72 hours at 15 – 25°C
12 months at ‑20 °C (Serum)
3 months at ‑15 to - 25°C (Plasma)
Transport: 2-25°C
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Specimen Rejection Criteria
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| Grossly hemolyzed, icteric and lipemic samples/ wrong collection container / |
| insufficient sample |
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Biological reference intervals and clinical decision values
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Interpretative data for HDL cholesterol as per NCEP guidelines:
< 1.04 mmol/L: Low HDL-cholesterol (major risk factor for CHD)
≥ 1.55 mmol/L: High HDL-cholesterol (negative risk factor for CHD)
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Turnaround time / Days and times test performed / Specimen retention time
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Daily (24/7)
Turn-around time:
Routine: One working day
Specimen Retention: 4 days
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