LP-IR Score: Normal Range, What It Means, and How It Is Calculated

The LP-IR score rates insulin resistance from 0 to 100 using six lipoprotein measurements. Labcorp reports a reference interval of 45 or below, and higher scores are linked to a higher risk of type 2 diabetes.

Published

August 29, 2024

Last updated

October 2, 2026

Read time

6 min read

Medically reviewed by

Rhonda Collins, FNP-C

Share

Copy link

What is the LP-IR score?

The Lipoprotein Insulin Resistance Index (LP-IR) score is a number from 0 to 100 that estimates how insulin resistant you are, where 0 is the most insulin sensitive and 100 is the most insulin resistant [Labcorp, 884095]. It is calculated from an NMR lipoprotein test rather than from glucose or insulin. Higher scores signal greater insulin resistance and a higher risk of type 2 diabetes.

Insulin resistance changes the size and number of the lipoprotein particles that carry fat and cholesterol in your blood. The LP-IR score was built to detect that pattern. It was developed against HOMA-IR in 4,972 adults without diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA), then checked against insulin clamp measurements in a separate group [Shalaurova et al., 2014].

What is a normal LP-IR score?

On Labcorp reports, the LP-IR reference interval is 45 or below, which is the 50th percentile of Labcorp’s reference population [Labcorp sample report, 884095]. A score of 46 or higher is flagged as high on the report. These values come from Labcorp’s own reference population, so read them as specific to the Labcorp test rather than as a universal standard.

The same Labcorp report places your score within its reference population:

Labcorp separately describes a score of 68 or higher as a clinical cutoff that indicates elevated insulin resistance and increased diabetes risk [Labcorp, 884095]. That cut-point comes from a Dutch cohort study of LP-IR and new cases of type 2 diabetes [Flores-Guerrero et al., 2019]. So a score of 25 sits in the lowest quarter of Labcorp’s reference population, a score of 50 sits above the reference interval, and a score of 70 is above Labcorp’s clinical cutoff.

Your result is only reliable from a fasting sample. Labcorp states that the LP-IR score is inaccurate if you were not fasting, and that it is a laboratory-developed index that should be used as one part of a clinician’s assessment [Labcorp sample report, 884095].

How is the LP-IR score calculated?

The LP-IR score combines six weighted lipoprotein measurements, each measured by nuclear magnetic resonance (NMR) spectroscopy, into one score from 0 to 100 [Labcorp, 884095]. The six inputs are:

• Large VLDL particle concentration
• Small LDL particle concentration
• Large HDL particle concentration
• VLDL particle size
• LDL particle size
• HDL particle size

On Labcorp’s report, the insulin resistant direction for each input is more large VLDL particles, more small LDL particles, fewer large HDL particles, larger VLDL particles, smaller LDL particles and smaller HDL particles [Labcorp sample report, 884095]. The weights themselves were set in the original derivation study, which found that the combined score tracked insulin resistance more closely than any single lipoprotein measure or the triglyceride to HDL cholesterol ratio [Shalaurova et al., 2014].

What does a high and low LP-IR score mean?

A high LP-IR score suggests a higher degree of insulin resistance and a higher risk of developing type 2 diabetes. It reflects a lipoprotein profile with more small LDL particles, fewer large HDL particles and more large VLDL particles, the pattern seen with insulin resistance, metabolic syndrome and type 2 diabetes [Labcorp, 884095].

A low LP-IR score indicates a lipoprotein profile consistent with better insulin sensitivity and a lower risk of type 2 diabetes. It usually corresponds to fewer small LDL particles and more large HDL particles.

A high score can appear before other markers look abnormal. In the MESA derivation study, some people had high LP-IR scores (50 or above) despite a normal body mass index or a fasting glucose below 100 mg/dL [Shalaurova et al., 2014].

What does a high LP-IR score mean for diabetes risk?

In cohort studies, higher LP-IR scores are associated with a higher chance of developing type 2 diabetes. These studies show an association in groups of people. They do not tell you whether you will develop diabetes.

In the Dutch PREVEND study of 5,977 adults without diabetes, followed for a median of 7.5 years, people in the highest quarter of LP-IR scores were about 10 times as likely to develop type 2 diabetes as those in the lowest quarter after adjusting for age and sex. After adjusting for other clinical risk factors, the difference was smaller, at about 3 times, but remained significant [Flores-Guerrero et al., 2019].

In the Women’s Health Study of 25,925 women aged 45 or older without diabetes, followed for a median of 20.4 years, each standard deviation higher LP-IR score was associated with a 1.95 times higher hazard of type 2 diabetes. After also adjusting for HbA1c, triglycerides and cholesterol, the hazard ratio was 1.41, and the association held even in women with optimal clinical profiles [Harada et al., 2017].

LP-IR vs HOMA-IR, fasting insulin and HbA1c

These markers look at blood sugar regulation from different angles, so they complement each other rather than substitute for one another.

• LP-IR score: estimates insulin resistance from the pattern of six lipoprotein particle measurements on a 0 to 100 scale.
• HOMA-IR: estimates insulin resistance from fasting glucose and fasting insulin. Its result is on a different scale from LP-IR.
• Fasting insulin: measures how much insulin is in your blood after a fast.
• HbA1c: reflects your average blood glucose over about the past three months, and is used to diagnose prediabetes and diabetes.

LP-IR and HOMA-IR are moderately correlated (r = 0.51 in MESA) [Shalaurova et al., 2014]. Labcorp notes that HOMA-IR varies a lot from one test to the next in the same person, and that LP-IR reflects both liver and peripheral insulin resistance [Labcorp, 884095]. HbA1c measures glucose rather than insulin resistance: the NIDDK defines prediabetes as an A1C of 5.7% to 6.4% [NIDDK]. In the Women’s Health Study, LP-IR remained associated with diabetes risk after adjusting for HbA1c [Harada et al., 2017].

Which test gives you an LP-IR score?

The LP-IR score comes from NMR lipoprotein testing that includes insulin resistance markers. Other particle tests do not report it.

At Mito, the LP-IR score is reported by the Labcorp NMR LipoProfile with insulin resistance markers, available through the NMR lipoprotein fractionation panel. That panel is also offered through Quest Diagnostics, and the Quest NMR lipoprotein fractionation test does not report an LP-IR score, so make sure your order goes to Labcorp if you want one. Ion Mobility lipoprotein panels and ultracentrifugation lipoprotein tests do not report an LP-IR score either.

The same Labcorp test also reports each of the six lipoprotein inputs, so you can see which ones are driving your score. Fast before your blood draw so the score is valid.

How do I lower my LP-IR score?

The LP-IR score reflects insulin resistance. The NIDDK lists consuming healthy foods and drinks, being physically active, managing your weight and getting enough sleep as habits that support metabolic health [NIDDK]. To see whether changes are working, retest with the same lab and fast before each draw so the results are comparable.

For more on this, see how to improve your LP-IR score naturally.

When to see a clinician

Talk with a clinician if your LP-IR score is above Labcorp’s reference interval, especially alongside a raised HbA1c, fasting glucose or fasting insulin, so they can interpret it with your other results.

Related LP-IR Score Resources

• How to Improve Your LP-IR Score Level Naturally

• HOMA-IR

• Fasting Insulin

Frequently asked questions

What is a normal LP-IR score?

On Labcorp reports, the LP-IR reference interval is 45 or below, which is the 50th percentile of Labcorp's reference population. Scores below 27 fall in the lowest quarter of that population and scores above 63 fall in the highest quarter. Labcorp describes a score of 68 or higher as a clinical cutoff for elevated insulin resistance and increased diabetes risk. These values are specific to Labcorp's test.

How is the LP-IR score calculated?

The LP-IR score combines six weighted lipoprotein measurements from an NMR lipoprotein test into one score from 0 to 100. The six inputs are the concentrations of large VLDL, small LDL and large HDL particles, and the average sizes of VLDL, LDL and HDL particles. The test needs a fasting blood sample, because Labcorp states that the score is inaccurate if you are not fasting.

How do I lower my LP-IR score?

The LP-IR score reflects insulin resistance. The NIDDK lists healthy eating, physical activity, weight management and enough sleep as habits that support metabolic health. Retesting with the same lab and fasting before the draw makes a later score comparable with your first one.

What is a normal insulin resistance score?

It depends on which score you mean. For the LP-IR score, Labcorp reports a reference interval of 45 or below on a 0 to 100 scale. HOMA-IR is a different calculation, made from fasting glucose and fasting insulin, and its result is on a different scale, so an LP-IR result and a HOMA-IR result cannot be compared number for number.