WedMD and MedlinePlus offer information on triglyceride levels. High triglyceride levels contribute to heart disease, WebMD explains. It is therefore recommended that anyone over the age of 20 check triglyceride levels at least every five years.
A normal triglyceride level is below 150 milligrams per deciliter, according to MedlinePlus. A high level ranges from 200 to 500 milligrams per deciliter, and a level above 500 is considered very high. Diet is a significant contributing factor to triglyceride levels.
Doctors use tests called lipid panels to check triglyceride levels, says WebMD. This test generally involves drawing blood from a vein inside the elbow or on the back of the hand, explains MedlinePlus.