The VLDL cholesterol concentration is expressed as

percent of total cholesterol.

Triglycerides (GPO/PAP Method)

(Courtesy: Tulip Group of Companies)

For the determination of triglycerides in serum or plasma

(for in vitro diagnostic use only).

Summary

Triglycerides are a form of fatty acid esters. They are

produced in the liver by binding glycerol and other fatty

acids. They are transported by VLDL and LDL and act as

a storage source for energy. Increased levels are found

in hyperlipidemias, diabetes, nephrotic syndrome,

hypothyroidism. Increased levels are risk factor for

arteriosclerotic coronary disease and peripheral vascular

disease. Decreased levels are found in malnutrition and

hyperthyroidism.

Principle

Lipoprotein lipase hydrolyzes triglycerides to glycerol and free

fatty acids. The glycerol formed with ATP in the presence of

glycerol kinase forms glycerol 3 phosphate which is oxidized

by the enzyme glycerol phosphate oxidase to form hydrogen

peroxide. The hydrogen peroxide further reacts with phenolic

compound and 4-aminoantipyrine by the catalytic action of

peroxidase to form a red colored quinoneimine dye complex.

Intensity of the color formed is directly proportional to the

amount of triglycerides present in the sample.

 Lipoprotein Lipase

Triglycerides Glycerol + Free fatty acids

 Glycerol Kinase

Glycerol + ATP Glycerol 3 Phosphate + ADP

 Glycerol 3 PO

Glycerol 3 Phosphate + O2 Dihydroxyacetone

phosphate + H2O2

Clinical Chemistry 489

 Peroxidase

H2O2 + 4 Aminoantipyrine Red + Phenol

Quinoneimine dye

+ H2O

Normal Reference Values

Serum/plasma (Suspicious) : 150 mg/dL and above

(Elevated) : 200 mg/dL and above

It is recommended that each laboratory establish its

own normal range representing its patient population.

Contents 25 mL 2 × 75 mL

L1: Enzyme Reagent 1 20 mL 2 × 60 mL

L2: Enzyme Reagent 2 5 mL 2 × 15 mL

S: Triglycerides Standard (200 mg/dL) 5 mL 5 mL

Storage/Stability

Contents are stable at 2–8°C till the expiry mentioned on

the labels.

Reagent Preparation

Reagents are ready to use.

Working reagent: Pour the contents of 1 bottle of L2

(Enzyme reagent 2) into 1 bottle of L1 (Enzyme reagent

1). This working reagent is stable for at least 8 weeks when

stored at 2–8°C. Upon storage the working reagent may

develop a slight pink color however, this does not affect

the performance of the reagent. Alternatively for flexibility

as much of working reagent may be made as and when

desired by mixing together 4 parts of L1 (Enzyme reagent

1) and 1 part of L2 (Enzyme reagent 2). Alternatively

0.8 mL of L1 and 0.2 mL of L2 may also be used instead

of 1 mL of the working reagent directly during the assay.