Insulin resistance

Tests

There is no one test that can directly detect insulin resistance. Instead, a doctor will look at a patient’s entire clinical picture and may suspect that the patient has insulin resistance if s/he has increased glucose levels, increased levels of triglycerides and LDL and decreased concentrations of HDL. Laboratory tests most likely to be ordered include:

Glucose. This is usually performed fasting but, in some cases, a doctor may also order 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 patient has an impaired response to glucose.
Lipid profile. This measures the HDL, LDL, triglycerides, and total cholesterol. If the triglycerides are significantly elevated, a DLDL (direct measurement of the LDL) may need to be done.

Other laboratory tests that may be ordered to help evaluate insulin resistance and provide additional information include:

Insulin. The fasting insulin test is variable, but insulin levels will usually be elevated in those with significant insulin resistance. Measurement of insulin concentrations during a GTT, sometimes with more frequent sampling, is occasionally also performed.
hs-CRP. This is a measure of low levels of inflammation that may be done as part of an evaluation of cardiac risk. It may be increased with insulin resistance.
Specific insulin suppression tests, measurement of sdLDL, and an Insulin Tolerance Test (ITT) may also be ordered in a research setting to study insulin resistance but are not generally used in a clinical setting.