Triglycerides

Also known as TG, trigs, triglyceride

lipid class · no single molecular formula

LOINC 2571-8 code verified serum mg/dL

What this substance is

Not one compound but thousands: a glycerol backbone esterified with three fatty acids of varying length and saturation. The assay reports the summed concentration of the whole family, so no single SMILES describes it. Triolein is often used as a representative for calibration.

Each molecule is drawn from ChEBI's curated 2D drawing, accepted only after its InChIKey, formula and charge matched the ChEBI release. Atom diagrams are checked against the NIST Atomic Spectra Database.

3D model · triolein

Triolein: one of thousands of triglycerides, with three oleic acid chains on a glycerol backbone. Generated by RDKit from ChEBI's verified structure, and accepted only because its own 3D geometry reproduces ChEBI's InChIKey. A flexible molecule takes many shapes; this is one low-energy one. Drag to rotate, scroll to zoom.

Reference ranges

Checking your own result against this range needs the running application; this is a static copy. Nothing you type anywhere in Empeiria is ever sent to a server.

Applies to	Normal	Optimal	Critical
all · fasting	≤ 150 mg/dL	—	—

guideline limit ATP III Guidelines At-A-Glance Quick Desk Reference, National Cholesterol Education Program (NHLBI) cited · not yet checked by a person

How it is measured

In practice

A health worker takes a small amount of blood from a vein in your arm. You may be asked not to eat or drink for 9 to 12 hours before the test. Your provider will tell you if you need to fast. Some expert groups now say fasting is not usually needed, because eating raises triglycerides only a little.

Venous blood sample. MedlinePlus describes a 9-12 hour fast when requested by the provider. The 2016 EAS/EFLM joint consensus recommends routine non-fasting lipid profiles: the maximal mean change 1-6 h after habitual meals is +0.3 mmol/L (26 mg/dL) for triglycerides, and fasting sampling may be considered when non-fasting triglycerides exceed 5 mmol/L (440 mg/dL). Non-fasting samples are flagged abnormal at triglycerides of 2 mmol/L (175 mg/dL) or more, fasting samples at 1.7 mmol/L (150 mg/dL) or more.

Before the test

Fast for 9 to 12 hours only if your provider asks you to.

Where: laboratory

Sources: Nordestgaard BG et al. Fasting is not routinely required for determination of a lipid profile: a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine. Eur Heart J 2016 (PMC open access); Triglycerides Test, MedlinePlus (U.S. National Library of Medicine) cited · not yet checked by a person

In the lab

enzymatic colorimetric

Lipase / glycerol kinase

The fats are broken apart to release glycerol, which is then measured. So the result is really the amount of glycerol, converted back into a fat figure.

Lipase releases glycerol, which is phosphorylated and oxidised to yield hydrogen peroxide for a Trinder endpoint.

What can throw it off

Free glycerol already present in the sample is counted as triglyceride and falsely raises the result.

Why labs disagree: Triglycerides rise after eating, on average by about 0.3 mmol/L (26 mg/dL) in the hours after a usual meal, so non-fasting samples are flagged at a higher cut-off (2 mmol/L, 175 mg/dL) than fasting ones (1.7 mmol/L, 150 mg/dL). Free glycerol already in the sample also pushes the result up.

Sources: Laboratory Procedure Manual, Triglycerides (Roche cobas), NHANES August 2021 - August 2023, CDC/NCHS; Nordestgaard BG et al. Fasting is not routinely required for determination of a lipid profile (EAS/EFLM joint consensus). Eur Heart J 2016 (PMC open access) cited · not yet checked by a person

What it reports on

liver synthesized by
The liver makes VLDL particles and releases them into the blood, and VLDL mainly carries triglycerides.

Associated symptoms

Conditions this marker features in

When high

high A cluster of risks that travel together · defining
One of the five criteria (three are needed): triglycerides consistently above 150 mg/dL. These are criteria for a risk-factor cluster, not a diagnosis of a single disease.
high Fatty liver · defining
One of the five cardiometabolic criteria (any one is enough, with fat in the liver): triglycerides 150 mg/dL or higher, or lipid-lowering treatment.
high Unhealthy cholesterol levels · defining
Classification, not a single diagnostic test: in the NCEP ATP III scheme triglycerides of 200–499 mg/dL are 'high' (150–199 borderline high).
high Blood sugar higher than normal, but not diabetes · supportive
High triglycerides often go with prediabetes, and a level above 250 mg/dL is one reason the ADA gives for testing adults with overweight.
high Type 2 diabetes · supportive
High triglycerides with low HDL is the most common lipid pattern in type 2 diabetes; a lipid panel is checked at diagnosis.

Ordered as part of

lipid · metabolic_risk