A high-density lipoprotein (HDL) test measures the level of good cholesterol in your blood. Cholesterol is a waxy substance that’s found in all of the cells in your body. … HDL is known as the good cholesterol because it carries LDL, triglycerides, and harmful fats and returns them to your liver for processing.
Why Get Tested:
- Advised to evaluate the coronary artery disease risk.
- This can be advised as the part of a lipid profile.
When to Get Tested:
- Screening: as part of a regular health exam with a lipid profile.
- when no risk factors for heart disease are present.
- once every four to six years in adults.
- children should have a lipid profile screening at least once between the ages of 9 and 11 and then again between the ages of 17 and 21.
- This test is done on the serum.
- Fasting sample is preferred. Advised the patient to fast for 12 to 14 hours.
- This test can be done on plasma as well.
- Can store serum or plasma at 4 °C for 4 days (can keep for 5 to 7 days).
- Male = 40 – 60 mg/dL
- Female = 40 – 60 mg/dL
Abnormal values of HDL:
- <25 mg/dl = Coronary heart disease risk is 2 times and this is a dangerous level.
- 26 to 35 mg/dl = The risk is 1.5 times. This is a high-risk group.
- 36 to 44 mg/dl = The risk is 1.2 times. This is a moderate risk group.
- 45 to 59 mg/dl = This is average risk group.
- Above 60 mg/dl = Below average risk group.
- Critical values:
- Male = less than 35 mg/dl.
- Female = less than 40 mg/dl.
Increased HDL-C value seen in:
- A chronic liver disease like cirrhosis, hepatitis, and alcoholism.
- Long-term vigorous exercises.
- Familial hyper- alpha-lipoproteinemia.
- The increased level may be due to some drugs.
- Estrogen therapy.
- Moderate intake of alcohol.
- Insulin therapy.
Decreased HDL-C values seen in:
- Poorly controlled diabetes
- Chronic renal failure, uremia, and nephrotic syndrome.
- Familial hypo-alpha-lipoproteinemia.
- alpha and beta – lipoproteinemia.
- The decreased level may also be seen in some of the drugs.
- Antihypertensive drugs.
Table showing the summary of characteristics of the lipoproteins
|PLasma appearance||Creamy layer, slightly turbid||Clear||Clear, or yellow-orange tint||Turbid to opaque|
|Size (diameter nm)||>70.0||4 to 10||19.6 to 22.7||25 to 70|
|Electrophoretic mobility||Origin||α – region||β – region||Pre – β region|
|Molecular weight||0.4 to 30 x 109||3.6 x 109||2.75 x 109||5 to 10 x 109|
|Synthesized in (Tissue of origin)||Intestine||Intestine and liver||Intravascular||Liver and intestine|
|Composition by weight in %|
|Cholesterol esterified||5||38||49||11 to 14|
|Cholesterol unesterified||2||10||13||5 to 8|
|Triglycerides||84||9||11||44 to 60|
|Phospholipids||7||22||27||20 to 23|
|Proteins||2||21||23||4 to 11|
|Triglycerides||Markedly raised||Normal||Normal/ Raised||Moderately to Markedly raised|
|Clinical significance of||Pancreatitis and acute abdomen||Decreased risk of CAD||Increased risk of CAD||Increased risk of CAD|
|Functions||Transport dietary lipids to tissue||Carry cholesterol from tissue to liver||Carries cholesterol to tissue||Transport endogenous TG from liver to adipose tissue|
Possible References Used