Lipid Profile Test for Cholesterol and Triglycerides: Why Do It?

The lipid profile or the lipid panel test comprises of a panel of tests, which include medical screening for any abnormalities that may be present in the blood values of cholesterol and triglycerides. The test requires you to be fasting for 9 to 12 hours.

The lipid profile test measures the levels of lipids in your blood. It helps in the diagnosis of dyslipidemia (lipid disorders) and includes the estimation of the blood values of the lipids, which include:

  • Total cholesterol, which is the sum total of all the cholesterol component in all the lipoprotein particles
  • High-density lipoprotein cholesterol (HDL -C) referred to as the good cholesterol because it removes any excess LDL cholesterol from the blood and carries it to the liver for removal from the body.
  • Low-density lipoprotein (LDL –C), which is referred to as the bad cholesterol because it is responsible for atherosclerosis, which increases the risk of heart disease.
  • Triglycerides most of which are present in very low-density lipoprotein (VLDL)

The analysis also enables to derive the cholesterol ratios, which help the doctor to evaluate your risks of cardiovascular problems.

The lipid profile lab report is usually available within a day or two.

An extended profile (or advanced lipid testing) may sometimes also be asked for. It measures the low-density lipoprotein particle number/concentration and is referred to as LDL-P.

The lipid profile measures the amount of cholesterol while the extended lipid profile measures the number of LDL particles. It is believed that this value more accurately reflects the risk of heart disease in some individuals. It also helps to monitor any ongoing treatment.

I have published the chart showing the normal and abnormal values of cholesterol and triglycerides for reference. You should refer to the chart to compare your lipid profile results.

Why do you need to take the lipid profile test?

As explained above, the lipid profile measures the blood levels of cholesterol and triglycerides.

High cholesterol and elevated triglycerides can cause serious life-threatening complications. But, unfortunately, these high levels do not announce themselves; meaning they do not cause any symptoms.

They are mostly detected during a routine blood checkup or when complications such as a heart attack or stroke develop.

That is why your health provider may routinely ask for the cholesterol and triglyceride testing when he deems fit. The indications for the lipid profile are explained below.

Secondly, you could do well to know the harm that these high lipids can have on you. You should read:

Preparing for the lipid profile test: Why fast, no alcohol and no smoking before the test?

The test is carried out with you fasting for 9 to 12 hours and an alcohol abstinence of a minimum of 24 hours – 48 hours is still better.

You should not eat any food or drink any fluids except water and your regular medication during the fasting period. Tea and coffee are also not recommended during the fasting period.

The reason is that triglyceride levels remain high for several hours after a meal and most reference values for serum lipids are based on fasting blood specimens.

The National Cholesterol Education Program (NCEP) and the European guidelines also recommend testing of the lipid profile of a fasting blood sample to assess cardiovascular risk of the person.

So, if you are giving your blood for testing in the morning, you should have finished your dinner 9 to 12 hours before reaching the laboratory.

Secondly, since alcohol can overnight cause an unwanted change in the lipid levels such as a rise in triglyceride and the LDL cholesterol levels, it is necessary to prevent this influence of alcohol over the lipid levels. Triglycerides and alcohol just don’t mix.

You will be asked to abstain from drinking alcohol for a period of 24 hours before giving your blood specimen for the test. Incidentally, some doctors recommend a 48-hour abstinence, which I personally feel is more idealistic because some levels of alcohol can linger on in the blood after 24 hours.

Fasting is necessary to obtain the correct values of total cholesterol, LDL cholesterol, and triglycerides.

Do not smoke, chew gum, or exercise during the fasting period. These activities alter test results.

After the blood is drawn, you can resume eating.

If your doctor has asked for only HDL values, fasting is not necessary because HDL values remain unaffected after a meal.

However, abstinence from alcohol is necessary for HDL, LDL, and triglycerides because alcohol will cause an artificial increase in their levels.

How are LDL levels calculated? The Friedewald equation

The measurement of LDL with an ultracentrifuge takes a lot of time besides being expensive and it also requires a special kind of equipment. For this reason, LDL cholesterol is most commonly estimated using the Friedewald equation.

The Friedewald equation is LDL cholesterol = total cholesterol − HDL cholesterol – triglycerides value/5. This equation uses fasting triglycerides values.

Norms for repeating lipid profile

If the test shows your levels to be normal, you can rest in peace. But, if your levels of cholesterol and/or triglycerides are elevated, it is advised that you repeat the lipid profile after two weeks in the same fasting state. This is to confirm your high levels.

The reason for this is that cholesterol or triglyceride lowering drugs once started can be a lifelong commitment.

A false picture can misguide the doctor into assessing your cardiovascular risk and prescribing of the medications and their doses. Repeating the test will help avoid this.

What other values are calculated from lipid profile report?

  • VLDL-C. Presently, there is no simple, direct way of measuring VLDL cholesterol. To estimate VLDL cholesterol (VLDL-C), divide the obtained triglyceride value by 5 if the measuring unit is in mg/dL or divide by 2.2 if the value is in mmol/L. Normal VLDL levels are from 2 to 30 mg/dL. This calculation is based on the composition of the VLDL lipoprotein.
  • Non-HDL cholesterol. This is calculated by total cholesterol minus HDL –C
  • Cholesterol ratios

When is the lipid profile asked for? Indications

The test may be ordered in adults and in children who are associated with one or more of the following risk factors.

In adults

  • Age.  A male 45 years or older or female 50-55 years or older
  • Hypertension
  • Diabetes or prediabetes
  • An existing heart disease
  • Family history of dyslipidemia (abnormal lipid levels in the blood)
  • Overweight or obese
  • Sedentary lifestyle with very little physical activity
  • Regular consumption of a diet high in saturated fats
  • Smoker
  • Heavy consumption of alcohol

Children and adolescents

The American Academy of Pediatrics (AAP) recommends that all children between the ages of 9 and 11 and again between 17 and 21 should be tested once.

However, children and adolescents with associated risk factors (same as those in adults) should be tested more often.

If you are on treatment for high cholesterol or triglycerides, you should repeat your lipid profile every 6 to 8 weeks till levels stabilize, after that, a six monthly repetition may be necessary or your doctor may ask for an annual checkup.

It depends on associated risk factors and how well you adhere to the natural means of maintaining your lipid levels (low-fat diet, regular exercise, and healthy lifestyle).

Lipid profile and diabetes

In well-controlled diabetes patients, lipid profile is often within normal limits.

During periods when blood sugar is poorly controlled in a diabetic, cholesterol and TG levels get affected. Triglycerides increase, LDL cholesterol and VLDL levels are elevated, and HDL cholesterol, the good cholesterol levels fall.

These statistics do not speak well regarding the health of the heart. The risk of developing a heart disease and stroke greatly increase with this type of picture of the lipid profile.

That is why when your blood sugar levels are not within the normal limits, your doctor may ask for the lipid profile test.

Relationship between lipid profile and hypertension

Results of studies confirm that hypertensive subjects are associated with an unfavorable lipid profile.

Hypertensive individuals exhibited significantly higher average levels of glucose, total cholesterol, LDL-C, HDL-C, triglycerides and HBAIc. However, there were no significant differences in the levels of Apo AI and Apo B.

Furthermore, the studies also indicate that high blood pressure treatment with beta-blockers is associated with lower levels of HDL cholesterol, whereas treatment with ACE inhibitors offers a small benefit on total cholesterol and LDL cholesterol. 

 

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