A doctor may suspect that a person has metabolic syndrome if he has central/abdominal obesity and a sedentary lifestyle, but both laboratory and non-laboratory tests are important in establishing the diagnosis. Recommended tests include:
- Glucose. Usually a fasting glucose test is performed but, in some cases, a doctor may also order a post prandial glucose (after a meal) or a GTT (glucose tolerance test – several glucose tests that are taken before and at timed intervals after a glucose challenge). The goal of glucose testing is to determine whether a person has an impaired response to glucose resulting in elevated blood glucose concentrations.
- Lipid profile. Measures HDL, LDL, triglycerides, and VLDL. If the triglycerides are significantly elevated, a DLDL (direct measurement of the LDL) may need to be done.
There are other laboratory tests that are not recommended for diagnosing metabolic syndrome but that may ordered by some doctors to provide additional information. They include:
- C-peptide. A reliable indicator of endogenous (a person's own) insulin production.
- Microalbumin. An early indicator of kidney disease, this test is used to help monitor diabetics and is recommended under the WHO criteria.
- hs-CRP. A measure of low levels of inflammation that may be tested as part of an evaluation of cardiac risk.
- sdLDL. A measurement of the number of small dense low-density lipoprotein molecules a person has. LDL varies in size, and the smaller denser molecules, which tend to form when elevated triglycerides and VLDL are present in the blood, are thought to be more aggressive in causing atherosclerosis. This test is now commercially available, but is not performed by many laboratories and is not ordered frequently. Its ultimate clinical utility has yet to be determined. It may be evaluated in a lipoprotein subfractions test.
- Insulin. The fasting insulin test is considered too variable to be clinically useful in diagnosing metabolic syndrome but, if measured, will usually be elevated in those affected.
Tests for which the clinical utility in diagnosing metabolic syndrome has not yet been established include plasminogen activator inhibitor-1 (PAI-1) and proinsulin.
- Blood pressure. To check for hypertension
- Weight and waist circumference. To document abdominal obesity
- BMI (Body Mass Index). An alternate measure of obesity that is used by many doctors. It is calculated by taking: (Weight in pounds X 705) / (height in inches squared); for example: (150 pounds X 705) / (67 inches X 67 inches) = a BMI of 23.5. An adult with a BMI greater than 30 is considered obese. This calculation does not, however, describe where the excess weight is on the body.