Triglycerides (TG)

What sample is needed for Triglycerides (TG)?

1. Ideally, this is done on the patient’s fasting serum. Venous blood is taken.
2. Fasting for 12 to 14 hours is required.
3. Plasma with EDTA can be used.
4. The sample is stable at 4 °C for 7 days and at -20 °C for 3 months.
5. If plasma is used, then multiply the result by 1.03.

What are the precautions for Triglycerides (TG)?

1. Patients must have fasted for at least 12 hours.
2. If TG in males is > 160 mg/dL and in females is > 135 mg/dL, two more samples should be taken in the next 6 to 8 weeks.
3. Intake of fatty meals may increase the TG.
4. Alcohol intake increases TG.
5. In pregnancy, the TG level is raised.
6. Take H/O drugs like oral contraceptives and estrogen to increase the TG level.
7. Take H/O ascorbic acid, clofibrate, and colestipol to decrease the TG level.
8. If TG >1000 mg/dL, it interferes with many laboratory tests. It predisposes to pancreatitis.
9. High alkaline phosphatase levels increase TG in all different methods.
10. Increased bilirubin, vitamin C, and uric acid interfere with some TG methods.
11. Serum values are about 2% to 4% less than the plasma.

What are the indications for Triglycerides (TG)?

1. This is done to evaluate the causes of atherosclerosis (Coronary artery disease).
2. This is done to evaluate turbid serum (milky).
3. Triglycerides are part of the lipid profile.
4. Triglyceride is advised in a patient with a suspected fat metabolism disorder.

How will you define Triglyceride (TG)?

• Triglycerides are the major form of fat found in nature, and their primary function is to provide energy for the cells.
• Most of the fatty acids in the body are part of Triglycerides and stored in the adipose tissue as fat.
• Triglyceride (TG) is primarily found in chylomicrons and VLDL.
• Triglyceride (TG)  provides a reasonable estimate of VLDL.
• Triglycerides are good risk factors for coronary heart disease, which is controversial.

How will you discuss the pathophysiology of Triglycerides (TG)?     

What are the sources of triglycerides?

1. Plants contain polyunsaturated fatty acids.
   1. Corn.
   2. Sunflower.
   3. Safflower.
2. Animal sources contain primarily saturated fatty acids and are solid at room temperature.
3. Glucose must be present in the cells for the formation of TG.
4. One of the sources gives the following ratio of triglycerides in various fats.

How will you describe the structure of triglycerides?

1. TG consists of three fatty acids + one molecule of glycerol by ester bonds, so-called Triglycerides.
2.  Glycerol and fatty acids are building blocks for TG.
3. Three fatty acids  + one molecule of glycerol (ester bond)  =  Triglyceride.
4. TG is present in the blood and transported by VLDL and LDL.

5. The glycolytic pathway in glucose catabolism leads to triglyceride formation.
6. This triglyceride formation may be absent in the case of:
   1. Fasting.
   2. Starvation.
   3. Uncontrolled diabetes mellitus.

How will you discuss Triglyceride catabolism?

1. TG, when catabolized, forms a small fraction of free fatty acid, which appears in plasma bound to albumin.
2. These nonesterified fatty acids, after oxidation, enter the Acetyl CoA cycle.
3. The end result is water, CO2, and ATP, the energy source.

How are the Triglycerides (TG) stored in the body?

1. Triglycerides (TG) are the fat in the bloodstream.
2. Triglycerides (TG) account for more than 90% of the food intake and are 95% of the fat stored.
3. Triglycerides (TG) are insoluble in water; this is the main glycerol ester.
4. TG is stored in adipose tissue as:
   1. Glycerol.
   2. Fatty acids.
   3. Monoglyceride.
5. The liver is the factory to convert all the above into triglycerides.

6. Triglycerides (TG) are transported and present in :
   1. 80% are in VLDL.
   2. 15% are in LDL.

7. TG is the source of energy.
8. When TG is high, it starts depositing in fatty tissue.
9. The Fredrickson-Levy classification method for hyperlipidemia: Refrigerate the plasma at 4 °C for 16 hours, and then observe the creamy layer at the top of turbidity.
   1. This can be completed by doing a lipid profile.

What are the normal Triglycerides (TG)?

Source 1

• To convert into SI unit x 0.0113 = mmol/L
• The recommended cutoff point for evaluating triglyceridemia status:
  • Normal = <250 mg/dL
  • Borderline high = 250 to 500 mg/dL
  • Hypertriglyceridemic = >500 mg/dL
  • High risk for pancreatitis = >1000 mg/dL

Source 2

• Male Adult = 40 to 160 mg/dL.
• Female Adult = 35 to 135 mg/dL.

Critical values of triglycerides are:

• Desirable = < 150 mg /dL.
• Borderline high = 150 to 199 mg /dL.
• High = 200 to 499 mg /dL.
• Very high = > 500 mg /dL.
• Critical value  >400 mg/dL

Triglycerides (TG) concentration, according to the National Cholesterol Education Program:

(Adult Treatment Panel (ATP) III).

What are the causes of increased Triglyceride values?

1. Hyperlipidemia.
2. Hyperlipoproteinemia.
3. Nephrotic syndrome.
4. Liver diseases.
5. Alcoholism (alcoholic cirrhosis).
6. Diabetes Mellitus, uncontrolled.
7. Glycogen storage disease (Von Gierke disease).
8. Familial hypertriglyceridemia.
9. Hypothyroidism.
10. Gout.
11. Anorexia nervosa.
12. Down’s syndrome.
13. Myocardial infarction.

What are the causes of decreased triglyceride levels?

1. Malnutrition.
2. Hyperthyroidism.
3. Congenital α-β- lipoproteinemia.
4. Malabsorption.

How will you manage Hypertriglyceridemia?

1. If Triglycerides (TG) are < 200 mg/dL, then the person needs diet control, and he should be advised to repeat triglycerides once a year.
2. If Triglycerides (TG) are 200 to 500 mg/dL, then evaluate the patient with risk factors like:
   1. Diabetes mellitus
   2. Alcoholism
   3. Hypothyroidism
   4. Hypertension
   5. Hyperuricemia
   6. Medications like beta-blockers, Estrogen, corticosteroids, and oral contraceptives.
   7. Diseases like kidney disease and pancreatitis.
3. No above risk factors in a person need only diet control
4. If a person has the above risk factors and a family history, these people need diet and medication.

What are the critical values of Triglycerides?

• If a person’s triglycerides is >500 mg/dL, these patients need diet control and medication.

Table showing the summary of characteristics of the lipoproteins:

Questions and answers:

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