LDL-Cholesterol (Low-density lipoprotein cholesterol)

Clinical definition of the LDL-Cholesterol test
Low-density lipoprotein (LDL) also called as the "bad" cholesterol is one of the five major groups of lipoproteins which enable lipids like cholesterol, triglycerides and other fats to be transported within bloodstream. They are named 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)

When too much LDL (bad) cholesterol circulates in the blood, it can slowly build up or clog the inner walls of the arteries that feed the heart and brain forming a plaque causing atherosclerosis which may lead to a heart attack or shock. The lower the LDL-C in the blood, the lower is the risk for heart disease or stroke.

Why is the LDL-Cholesterol test done?
This test is used to measure the level of LDL cholesterol in your blood which determines the patients risk for heart diseases. The LDL test is usually done as part of a lipid panel, which also checks total cholesterol, HDL, VLDL and triglyceride levels. As a part of the commonly done Lipid profile tests, medically and mathematically calculated LDL-C is generally reported. For cost as well as improved TAT (Turn-around -time) a Direct LDL measurement is done only when the calculation of LDL-C will not be accurate because the patient's triglycerides are significantly elevated, hence a higher risk for developing a heart related ailment.

What are the common signs/symptoms when the LDL-Cholesterol test is done?

  • Hypertension 
  • 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
  • Sweating
  • 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)

Who should do the LDL-Cholesterol test (Target population)?
It may be ordered more frequently for those who have may have risk factors for heart disease such as:

  • Age (men 45 years or older or women 55 years or older)
  • Overweight or obese people
  • Smokers
  • Heavy drinkers
  • People with a family history of heart disease or health problems such as diabetes, high blood pressure (hypertension),
  • People who consume excess of saturated fats - found mostly in animal products and trans-fatty acids -found in fast foods and commercially processed food products.
  • Pre-existing heart disease or those who have already had a heart attack

What should I do before the LDL-Cholesterol test?

Specimen type

Specimen collection procedure

Preparatory instructions during specimen collection*

Serum (Blood Sample)

Venipuncture - Collection of blood from a vein, usually from the arm.

Fasting Required.

Fasting samples have to be collected after a minimum 12-14 hour overnight fasting status.

Clear fluids like water is 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.

*Subjects suffering from any illness or on oral or injectable medications are advised to consult their physician prior to requesting any tests or procedures.

How do I interpret my LDL-Cholesterol test result?

Reference

Interpretation

Less than 100 mg/dL

optimal

100-129 mg/dL

near optimal/above optimal

130-159 mg/dL

borderline high

160- 189 mg/dL

high

190 mg/dL and above

very high

Inference: The lower the LDL cholesterol, the lower is the risk of developing a heart attack and stroke. A healthy LDL level is one that falls in the optimal or near-optimal range.
‘*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’

Related diseases/condition to the LDL-Cholesterol test

  • Atherosclerotic heart disease
  • Familial hyperlipoproteinemia
  • Malabsorption 
  • Malnutrition
  • Familial combined hyperlipidemia
  • Familial dysbetalipoproteinemia
  • Familial hypertriglyceridemia

Other related tests to LDL-Cholesterol

  • Cholesterol
  • HDL Cholesterol
  • Triglycerides
  • Lipid profile
  • Lp (a)
  • Apolipoprotein A-1
  • Apolipoprotein B (APO-B)
  • Cardiac risk profile
  • Lp-pla2

Book Related Tests
  • Cholesterol (Serum)
  • HDL Cholesterol
  • Lipid Profile
  • Triglycerides (Serum)

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