There’s an Insulin Resistance test, the homeostasis model assessment-estimated insulin resistance (HOMA-IR) but it requires a fasting insulin test for the calculation which is not a normal part of blood lipid tests. There’s also a surrogate for HOMA-IR called the Triglycerides/glucose index. Here’s a paper on it (B Kang, Y Yang, E Y Lee, H K Yang, H-S Kim, S-Y Lim, J-H Lee, S-S Lee, B-K Suh & K-H Yoon. Triglycerides/glucose index is a useful surrogate marker of insulin resistance among adolescents. International Journal of Obesity volume 41, pages 789–792).
The TyG index was calculated as ln [triglycerides (mg/dl) × fasting glucose (mg dl)/2]. IR was defined using HOMA-IR >95th percentile for age and sex.
The threshold is:
The cut-off of the TyG index for diagnosis of insulin resistance was 8.18.
I created an on-line calculator for this index.
Numbers less than 8.18 are not insulin resistant. My own numbers are:
- Triglycerides = 118
- Fasting Glucose = 103
- TyG = ln(118*103/2) = 8.71
Here’s how do this calculation in EXCEL:
I am still Insulin Resistant.
My numbers from 2015 (before Low Carb) were:
- Triglycerides = 460
- Fasting Glucose = 152
- TyG = ln(114*103/2) = 10.5
So I’m not where I want to be yet, but I’m long ways from where I was.
A Second Study
A second related study (Mohd Nor, N. S., Lee, S. , Bacha, F. , Tfayli, H. and Arslanian, S. (2016), Triglyceride glucose index as a surrogate measure of insulin sensitivity in obese adolescents with normoglycemia, prediabetes, and type 2 diabetes mellitus: comparison with the hyperinsulinemic–euglycemic clamp. Pediatr Diabetes, 17: 458-465.):
Insulin‐stimulated glucose disposal (Rd) declined significantly across the glycemic groups from OB‐NGT to OB‐preDM to OB‐T2DM with a corresponding increase in TyG index (8.3 ± 0.5, 8.6 ± 0.5, 8.9 ± 0.6, p < 0.0001). The correlation of TyG index to Rd was −0.419 (p < 0.0001).
The optimal TyG index for diagnosis of insulin resistance was 8.52 [receiver operating characteristic‐area under the ROC curves (ROC‐AUC) 0.750, p < 0.0001].
A Third Study
Here’s a third study with the same data but particular to diabetes (Prev Med. 2016 May;86:99-105. Triglyceride-glucose index (TyG index) in comparison with fasting plasma glucose improved diabetes prediction in patients with normal fasting glucose: The Vascular-Metabolic CUN cohort.
Navarro-González D, Sánchez-Íñigo L, Pastrana-Delgado J, Fernández-Montero A, Martinez JA.).
We observed a progressively increased risk of diabetes in subjects with TyG index levels of 8.31 or more. Among those with normal fasting glucose at baseline, <100mg/dl, subjects with the TyG index in the fourth quartile were 6.87 times more likely to develop diabetes (95% CI, 2.76-16.85; P for trend<0.001), as compared with the bottom quartile.
The areas under the ROC curves (95% CI) were 0.75 (0.70-0.81) for TyG index, 0.66 (0.60-0.72) for FPG and 0.71 (0.65-0.77) for TG, in subjects with normal fasting glucose (p=0.017).