Biomarker · Lipids

Triglycerides

Also known as: TG, triacylglycerol, serum triglycerides

The main form in which fat is stored and transported: three fatty acids on a glycerol backbone, carried in blood by chylomicrons after meals and by VLDL from the liver. Raised levels add to cardiovascular risk and very high levels can trigger pancreatitis.

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Also known as
TG, triacylglycerol, serum triglycerides
Units
mmol/L (UK) or mg/dL (US); 1 mmol/L ≈ 88.5 mg/dL
Measured by
Lipid profile, Blood glucose

What it is and what it does

After a fatty meal the gut packages triglyceride into chylomicrons, which is why a non-fasting sample reads higher and why laboratories once insisted on fasting. Between meals the liver exports triglyceride in VLDL, particularly when it is over-supplied with calories, alcohol or sugar, or when insulin resistance lets fat stores release fatty acids freely. Moderately raised triglycerides usually travel with low HDL, central obesity and prediabetes; levels above about 10 mmol/L carry a real risk of acute pancreatitis. Because triglyceride-rich particles contribute to non-HDL cholesterol, the lipid profile as a whole rather than the single number guides treatment.

Why it may be higher

  • A recent meal, alcohol, sugary and refined-carbohydrate-rich diets
  • Obesity, type 2 diabetes and insulin resistance, metabolic syndrome
  • Hypothyroidism, kidney disease, pregnancy
  • Medicines: corticosteroids, oestrogens, isotretinoin, some antipsychotics, thiazides, beta blockers
  • Inherited hypertriglyceridaemia (familial chylomicronaemia, familial combined hyperlipidaemia)

Why it may be lower

  • Malnutrition, malabsorption, hyperthyroidism
  • Fibrates, omega-3 preparations, statins to a lesser degree, weight loss

A high or low value can be associated with several different situations. The result is interpreted with other results, symptoms, history and clinical findings.

What can affect the result

  • Fasting versus non-fasting sampling (up to a few hours' difference)
  • Alcohol in the preceding days
  • Acute illness and pregnancy
Reference ranges. Reference intervals for this marker depend on the laboratory, the assay, the units, age, sex and pregnancy. Interpret a result against the interval printed on the laboratory report, not against a figure from the internet.
Educational content. A biomarker page explains what a substance is and why its level can change. It cannot determine the cause of your result: interpret a result using the range supplied by the laboratory that performed the test, with the clinician who ordered it.