McLaughlin 2003: TG/HDL Ratio for Insulin Resistance Screening

Background

In 2003, researchers at Stanford University led by Dr. Tracey McLaughlin faced a practical clinical problem: how can doctors easily identify which overweight patients are insulin resistant and at higher metabolic risk?

The gold standard—the euglycemic hyperinsulinemic clamp—costs hundreds of dollars, takes hours, and requires specialized equipment. Most clinics simply cannot offer it. Yet insulin resistance drives much of the metabolic disease epidemic.

The Study

McLaughlin's team recruited 258 overweight but non-diabetic volunteers from the San Francisco Bay Area. Each participant underwent:

• •Full metabolic testing including the clamp procedure
• •Standard lipid panel (triglycerides, HDL, LDL, total cholesterol)
• •Fasting insulin measurement

They then tested which simple markers best predicted insulin resistance as measured by the clamp.

Key Findings

The TG/HDL ratio emerged as a remarkably accurate screening tool:

• •Cut-point of 3.0: At this threshold, the ratio identified insulin-resistant individuals with 79% sensitivity (catches most cases) and 65% specificity (reasonable false-positive rate)
• •Practical utility: Any standard lipid panel provides the numbers needed—no additional testing required
• •Combined markers: Adding fasting insulin >15 μU/mL improved prediction further

Clinical Impact

This study transformed how many clinicians think about standard lipid panels. Rather than just looking at individual numbers, the TG/HDL ratio provides insight into underlying metabolic health.

The findings have been replicated in multiple populations and form the scientific basis for using TG/HDL ratio as a metabolic screening tool.