How to compare the two metabolic syndrome definitions
Enter waist circumference in inches, blood pressure, fasting glucose, triglycerides and HDL cholesterol, and the same numbers are run through both definitions. The revised NCEP ATP III criteria (AHA/NHLBI scientific statement, 2005) identify metabolic syndrome when any three of five components are present. The IDF 2005 definition makes central obesity a requirement and then looks for at least two of the remaining four components.
The shared thresholds are triglycerides of 150 mg/dL or more, HDL cholesterol below 40 mg/dL for men and below 50 mg/dL for women, blood pressure of 130 mmHg systolic or more or 85 mmHg diastolic or more, and fasting glucose of 100 mg/dL or more. The blood pressure fields are prefilled with 130/85 and can be edited. For waist, the ATP III side uses the US cut-offs of 40 inches or more for men and 35 inches or more for women (102 and 88 cm). The IDF side uses its cut-offs for people of European descent, 94 cm for men and 80 cm for women, which the page converts at 2.54 cm per inch (about 37.0 and 31.5 inches). IDF lists lower waist values for some other ethnic groups, such as South and East Asian populations. Current as of October 2026.
Both definitions also count a component as met when you are being treated with medication for it, but this page only compares the numbers you enter. The count of met criteria is not a score and nothing is weighted. This is not a medical diagnosis, and the interpretation of these numbers belongs with a clinician who sees the whole panel.
Frequently asked questions
Both the revised NCEP ATP III criteria (AHA/NHLBI 2005) and the IDF 2005 definition count the blood pressure component as systolic 130 mmHg or higher or diastolic 85 mmHg or higher. Those values are prefilled; you can change them if you are working from a different threshold.
The ATP III side uses the US waist cut-offs of 40 inches or more for men and 35 inches or more for women (102 and 88 cm). The IDF side uses the IDF cut-offs for people of European descent, 94 cm or more for men and 80 cm or more for women, which is about 37.0 and 31.5 inches. Because the IDF values are lower, someone can meet the IDF waist prerequisite without meeting the ATP III waist criterion.
Central obesity is required. On top of it, at least 2 of the other 4 components (triglycerides, HDL cholesterol, blood pressure, fasting glucose) must be met. Without central obesity the IDF definition does not apply even if all four of the others are met.