Triglyceride to HDL ratio calculator

The formula

The ratio is triglycerides divided by HDL cholesterol, both from the same cholesterol test. The number depends on the units. Most US labs report mg/dL, and the study's cut point of 3.0 is in those units (McLaughlin 2003). For example, triglycerides of 150 mg/dL and HDL of 50 mg/dL give 150 ÷ 50 = 3.0.

If your lab reports mmol/L, the same blood gives a smaller ratio, about 0.44 times the mg/dL ratio. We convert triglycerides with 88.57 and HDL cholesterol with 38.67 and show both numbers, but compare only the mg/dL ratio with the cut point.

What the study found

The study measured how well insulin moved sugar out of the blood in 258 overweight people without diabetes and called the third with the weakest response insulin resistant. Triglycerides, the triglyceride to HDL ratio and fasting insulin were the most useful of the blood markers tested. The best cut point for the ratio was 3.0 in mg/dL units. At that cut point the ratio found 64% of the insulin-resistant people (sensitivity) and correctly cleared 68% of the others (specificity) (McLaughlin 2003).

The authors suggested that, without a standard insulin test, the triglyceride level or the triglyceride to HDL ratio is the most practical way to pick out overweight people who are insulin resistant (McLaughlin 2003).

Reading your result with care

• The 3.0 cut point comes from one study of overweight adults without diabetes. It may not apply to people of other weights or to people who already have diabetes.
• About a third of the insulin-resistant people in the study had a ratio below 3.0, and about a third of the others had a ratio at or above it (McLaughlin 2003).
• The study abstract also gives "1.8 in SI units" for this cut point. Converting 3.0 from mg/dL with the standard factors gives about 1.3, not 1.8, so we use only the mg/dL figure, which is the one the study gives for traditional units.
• The abstract does not say whether a ratio of exactly 3.0 counts as above or below; we count it as at or above.
• It does not give a chance of a heart attack or stroke. For that, use a heart risk calculator that also counts age, blood pressure, smoking and diabetes, such as the PREVENT heart risk calculator.

Your triglycerides and HDL on their own

Each number in the ratio has its own adult ranges, and those are what your clinician will look at. High triglycerides together with high LDL or low HDL cholesterol add to heart risk (MedlinePlus). See triglyceride levels for the triglyceride categories, and the LDL calculator for LDL, HDL and non-HDL ranges (MedlinePlus).

Related research indexes

Several research markers build on the same two numbers. The atherogenic index of plasma (AIP) is the base-10 logarithm of this ratio in mmol/L. The cardiometabolic index multiplies the mg/dL ratio by the waist-to-height ratio. Remnant cholesterol is total cholesterol minus LDL and HDL, the cholesterol in triglyceride-rich particles. For insulin resistance, the TyG index pairs fasting triglycerides with fasting glucose, METS-IR combines triglycerides, HDL, fasting glucose and BMI, and HOMA-IR uses fasting insulin and glucose. None of these diagnoses a disease.

Getting the right numbers

Use triglycerides and HDL cholesterol from the same cholesterol test. You may be asked to fast for 9 to 12 hours before it (MedlinePlus). If you compare the ratio over time, use results taken the same way each time, fasting or not.