clinical definition of hdl cholesterol (high-density lipoprotein cholesterol)
High-density lipoprotein (HDL) commonly known as "good" cholesterol is one of five major groups of lipoproteins which allow lipids like cholesterol, triglycerides and other fats to be carried within the bloodstream. They are categorized in order of their sizes i.e. from the smallest to the largest as follows:
- Very low-density lipoprotein (VLDL)
- low-density lipoprotein (LDL)
- Intermediate density lipoprotein (IDL)
- high-density lipoprotein (HDL)
HDL helps absorb the excess of cholesterol from the walls of blood vessels and tissues of the body. It is then transported to the liver where it first clumps and then eventually removed or excreted in the form of bile. HDL cholesterol is therefore considered the "good" cholesterol. Any individual who has high levels of HDL is at a lower risk of a heart attack, stroke, or other cardiovascular problem.
what is hdl test?
The High-Density Lipoprotein Test or the HDL Test measures the amount of good cholesterol in the body of the patient. Cholesterol, as we know, is found in all the cells of the body. It is important in helping the body carry out a lot of functions, like building cells and the likes. The lipoproteins in the blood are responsible for carrying the cholesterol through the body.
Cholesterol can be broadly divided into two types- High-Density Lipoprotein and Low-Density Lipoprotein. The former is known as the ‘good’ cholesterol, while the latter the ‘bad’. HDL helps bodily functions like transfer of LDL, triglycerides, and other fats back to the liver for processing, from where it is broken down and removed from the body. LDL, however, is the cholesterol which is more common in the body.
It is considered to be unhealthy since it can cause blockages in the arteries and makes the body susceptible to cardiac conditions. Since the HDL is what helps carry off the LDL to the liver, the HDL levels of the body are important. It has been shown that HDL levels in the normal range mean that the person is at a lower risk of heart conditions.
why do i need hdl test?
If the patient is at a higher risk of heart disease, the doctors will be sure to recommend this test to check the HDL cholesterol levels. This includes people who are affected by diabetes or have a history of heart disease in their families.
Men over the age of 45 and women over 55 are also naturally at an increased risk, along with people who have been diagnosed with high blood pressure. Tobacco-users will also be checked for the onset of cardiac conditions.
when do you expect results?
The test results of the HDL blood test can be expected within 36 hours after the blood sample has been given.
why get tested?
An HDL is ordered as part of an overall lipid profile along with other lipid tests like cholesterol, LDL-"bad" cholesterol, and triglycerides. The combined information gathered from all of these tests may help assess the risk of heart diseases. It could be done as part of a lipid profile during a health check-up which is advised periodically in adults depending on their lifestyle.
The results of the test give the doctor a comprehensive idea about the condition of the body, and the onset of any heart conditions if any. The HDL cholesterol test looks specifically at the HDL levels in your bloodstream, and the doctor may order a follow-up if you have high results in the cholesterol-screening test. Adults over the age of 20 would do well to check the condition of the cholesterol at least once every 4 to 6 years.
reason to take hdl cholesterol (high-density lipoprotein cholesterol) test
Some of the symptoms that point towards an HDL test are:
- Shortness of breath
- Headaches Pain, fullness, and/or squeezing sensation of the chest, Jaw pain, toothache, headache
- Nausea, vomiting, and/or general epigastric (upper middle abdomen) discomfort
- Heartburn and/or indigestion
- Arm pain (more commonly the left arm, but may be either arm)
- Upper back pain
- General malaise (vague feeling of illness)
preparations needed for hdl cholesterol (high-density lipoprotein cholesterol) test
Preparatory instructions during specimen collection*:
- Fasting Required.
Fasting samples have to be collected after a minimum 12-14 hour overnight fasting status.
Clear fluids like water are allowed during this period. Refrain from consumption of early morning beverages like tea, coffee and milk until specimen collection is completed.
In case of diabetics on oral or injectable hypoglycemic agents, consult your physician about continuing with these medications prior to specimen collection.
If you have been sick recently or coming right off a stressful event like a surgery or an accident, the HDL cholesterol test is not advised at the time. This is because the cholesterol levels in the blood are temporarily lower right after these events.
In this case, you might have to wait at least 6 weeks after the event for the cholesterol levels to get back to normal in the body. Pregnancy also affects the amount of HDL in the body, so you should wait until six weeks post-delivery to get an accurate result.
Specimen type: Serum (Blood Sample)
Specimen collection procedure: Venipuncture - Collection of blood from a vein, usually from the arm.
does hdl test pose any risk?
The only thing required to test the HDL normal range in the body is a sample of blood, so the test is almost risk-free. However, in rare cases, the person may be affected by bleeding under the skin, excessive bleeding, infection at the wounded area or fainting after the blood has been drawn from the body.
Understanding results of HDL Cholesterol (High-density lipoprotein cholesterol)
|Less than 40 mg/dL (men)||increased risk of heart disease|
|Greater than 60mg/dL||protective against heart disease|
|Less than 50: mg/dL (women)||increased risk of heart disease|
‘*A Reference range is a set of values which helps the healthcare professional to interpret a medical test. It may vary with age, gender, and other factors. Reference ranges may also vary between labs, in value & units depending on instruments used and method of establishment of reference ranges’