7 Blood Tests That Can Shed Light on Your Metabolic Health
Published on July 27, 2026
While “normal” lab results may be reassuring, they don’t automatically mean someone is metabolically healthy.
Metabolic health is typically assessed using five key markers — waist circumference, blood pressure, blood sugar, triglycerides, and HDL (or “good”) cholesterol — that reflect how well the body is processing sugar and fat. While values outside of the “normal” range increase the risk of conditions like heart disease, type 2 diabetes, stroke, and fatty liver disease, metabolic risk can still be present even when standard lab results appear normal.
“Metabolic bloodwork results can flag risks before symptoms appear, but they usually do not tell the full story on their own,” says Evans Osuji, MD, an internal medicine physician at Johns Hopkins University Department of Medicine in Baltimore.
That’s why interpreting key blood work markers together — rather than in isolation — can reveal early clues about metabolic health and guide prevention long before chronic disease develops.
1. Hemoglobin A1C
Hemoglobin A1C (HbA1C), also known as A1C, is a standard test used to diagnose prediabetes and diabetes. It reflects average blood sugar over the previous three months by tracking how much glucose attaches to red blood cells — offering a long-term view of blood sugar control rather than a single snapshot in time. Because of this, HbA1C can help identify metabolic dysfunction that develops gradually years before diabetes is formally diagnosed.
An A1C result between 5.7 percent and 6.4 percent falls into the prediabetes range, while 6.5 percent or higher may indicate diabetes. Elevated HbA1C is also associated with an increased risk of heart disease and metabolic syndrome.
Poll
Which metabolic health marker are you most concerned about?
2. Fasting Blood Glucose
Fasting blood glucose measures blood sugar after an overnight fast, offering a snapshot of how well the body is regulating glucose at a single point in time.
But it may not fully reflect day-to-day fluctuations or early insulin resistance (the hallmark of type 2 diabetes) that has not yet affected glucose levels. “A normal fasting result is useful, but it does not capture how blood sugar responds after meals, so it is often interpreted alongside A1C and other risk markers,” Dr. Osuji says.
A result of 100 milligrams per deciliter (mg/dL) to 125 mg/dL falls into the prediabetes range, while anything higher may indicate diabetes. In addition to diabetes, impaired fasting glucose may be an early marker of broader metabolic dysfunction.
3. Fasting Insulin
While glucose tests measure sugar, fasting insulin reveals how hard the body is working to keep those levels normal.
Insulin is the hormone that moves glucose from the bloodstream into cells for energy. When cells become resistant to it (called insulin resistance), the body produces even more insulin to compensate — often years before blood sugar becomes abnormal. That means someone can still have “normal” glucose, while insulin levels are already elevated behind the scenes.
Some clinicians also use HOMA-IR (homeostatic model assessment of insulin resistance) — a formula that combines fasting insulin and fasting glucose number — to estimate insulin resistance. Higher scores are associated with an increased risk of metabolic syndrome, fatty liver disease, and type 2 diabetes — even when glucose levels are still normal.
Although fasting insulin isn’t a routine diagnostic test for diabetes, many clinicians see it as a helpful early-detection tool for assessing metabolic health and insulin resistance.
“Metabolic syndrome criteria are useful clinically but do not capture all at-risk individuals,” says Maram Khalifa, MD, an endocrinologist and an assistant professor of medicine at UConn Health in Farmington, Connecticut. “Additional markers such as insulin levels, ApoB, liver enzymes, and CRP often provide deeper risk assessment.” Not all insurance plans cover this test. Even when it’s ordered appropriately, reimbursement can be inconsistent because guidelines don’t universally endorse fasting insulin for routine screening.
4. Triglyceride/HDL Ratio
The triglyceride-to-HDL (or “good”) cholesterol ratio reflects how the body processes sugar and fat — and may provide more insight into metabolic risk than LDL cholesterol alone.
Higher triglycerides and lower HDL levels are often linked to insulin resistance and excess belly (visceral) fat, making this ratio a useful proxy marker of metabolic health. “It’s not used alone to diagnose disease, but it can add useful context when reviewing a person’s overall metabolic risk,” Osuji adds.
Research links higher ratios with an increased risk of insulin resistance, metabolic syndrome, and heart disease. Many experts consider a ratio under 2.0 to be a healthy target, but ideal ranges can vary based on individual risk factors and the laboratory.
5. VDL and Remnant Cholesterol
VLDL (very low density lipoprotein) cholesterol particles carry triglycerides through the bloodstream to be used or stored for energy. As these particles circulate and triglycerides are removed, leftover “remnant” particles can contribute to plaque buildup in the arteries, increasing the risk for heart disease and stroke. Research suggests that when metabolism is impaired, VLDL production may increase.
Elevated remnant cholesterol — often higher than about 24 mg/dL — has been linked to increased cardiometabolic risk, including heart disease and type 2 diabetes. “Elevated levels often reflect overproduction of triglycerides, commonly seen in insulin resistance and fatty liver disease,” Dr. Khalifa says.
VLDL cholesterol levels above roughly 30 mg/dL are typically considered elevated in clinical practice.
6. ApoB (Apolipoprotein B)
ApoB (apolipoprotein B) measures the number of potential plaque-forming particles circulating in the bloodstream — not just the cholesterol they carry. Because each LDL, VLDL, and remnant cholesterol particle contains one ApoB protein, higher levels (generally above 130 mg/dL) indicate more plaque-forming particles overall.
So in some cases, LDL could appear normal while ApoB is elevated — which is why clinicians note this marker may be a clearer predictor of metabolic risk. “Many experts consider ApoB a stronger risk marker than LDL cholesterol alone, especially for predicting heart attack and stroke risk in people with high triglycerides, diabetes, obesity, or metabolic syndrome,” Osuji says. While insurance coverage of this test has been improving because multiple guidelines now recognize ApoB to determine individuals’ health risks, not all insurance plans cover it.
ALT (alanine aminotransferase) and AST (aspartate aminotransferase) are enzymes that can rise when the liver is under stress.
Elevated ALT and AST levels may be an early sign of nonalcoholic fatty liver disease (NAFLD), a liver condition strongly linked to insulin resistance and metabolic dysfunction that often develops silently without noticeable symptoms initially. “Even mild liver enzyme elevations, particularly ALT, commonly suggest [NAFLD] in patients with obesity or insulin resistance,” Khalifa says.
An increase in ALT (typically above 45 International Units per liter, or IU/L) or AST (above 35 IU/L) can also be triggered by other factors. “These markers are not specific to fatty liver disease, so clinicians also consider alcohol use, medications, supplements, infections, and other possible causes,” Osuji says.
7. hs-CRP (High-Sensitivity C-Reactive Protein)
Hs-CRP (high-sensitivity C-reactive protein) measures low-grade inflammation in the body. Higher levels (usually above 2 mg/L) are associated with an increased risk of heart disease and metabolic disorders — even when cholesterol is normal.
Experts say hs-CRP offers a broader view of metabolic stress, rather than the more focused snapshot provided by other measurements, like cholesterol or blood sugar. “It’s not a standalone diagnosis, but it can add useful context when interpreted alongside blood sugar, cholesterol, blood pressure, and other risk markers,” Osuji adds. While hs-CRP is helpful in evaluating CV and metabolic risk, this test is nonspecific and can go up for many reasons including viral URI, any kind of infections, surgery, recent vaccinations, injury, and intense exercise.
What to Know Before Your Next Metabolic Blood Test
Metabolic risk can develop for years before blood work comes back abnormal. That’s because standard laboratory reference ranges are typically designed to detect existing disease — not optimal metabolic health.
“The standard range represents what’s statistically normal within a population, while an optimal range is associated with the lowest long-term cardiometabolic risk,” Khalifa explains.“So a patient may have ‘normal’ labs yet show early trends toward metabolic dysfunction.”
Preparation can also meaningfully influence results, and consistent testing improves trend interpretation over time.
“Timing matters, as consistency improves trend interpretation,” Khalifa says, recommending the following tips ahead of a metabolic health panel:
- Complete an 8–12 hour fast for glucose, insulin, and triglycerides
- Avoid strenuous exercise for 24 hours before testing
- Aim for morning draws when possible for consistency
- Be aware that factors like illness and stress can temporarily affect results
Ultimately, most clinicians emphasize that blood work is most useful when viewed as a long-term trend rather than a single snapshot.
“Metabolic bloodwork should be framed as a guide for understanding risk and deciding what to do next — not as a pass-or-fail grade,” Osuji says. “Metabolic health can often improve with the right steps.”
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
- What Is Metabolic Syndrome? American Heart Association. October 17, 2023.
- How to Understand Your Lab Results. MedlinePlus. September 4, 2025.
- Hemoglobin A1C (HbA1c) Test. MedlinePlus. May 15, 2024.
- A1C Test for Diabetes and Prediabetes. Centers for Disease Control and Prevention. May 15, 2024.
- Mehta M et al. Insights into HbA1c: Key Role in Diabetes Screening and Associated Conditions” — a Comprehensive Review. Journal of Pharmacy and Bioallied Sciences. June 18, 2025.
- What Is the A1C Test? American Diabetes Association.
- Diabetes Testing. Centers for Disease Control and Prevention. May 15, 2024.
- Diabetes Diagnosis. American Diabetes Association.
- Song J et al. Non-linear Associations of Cardiometabolic Index with Insulin Resistance, Impaired Fasting Glucose, and Type 2 Diabetes Among US Adults: A Cross-sectional Study. Frontiers in Endocrinology. Feruary 11, 2024.
- Insulin in Blood. MedlinePlus. August 7, 2023.
- About Insulin Resistance and Type 2 Diabetes. Centers for Disease Control and Prevention. May 15, 2024.
- The Difference Between Insulin Resistance and Prediabetes. Nebraska Medicine. August 31, 2022.
- Tsai SF et al. Development and Validation of an Insulin Resistance Model for a Population Without Diabetes Mellitus and its Clinical Implication: a Prospective Cohort Study. eClinicalMedicine. April 4, 2023.
- Lee J et al. Assessment HOMA as a Predictor for New Onset Diabetes Mellitus and Diabetic Complications in Non-diabetic Adults: A KoGES Prospective Cohort Study. Clinical Diabetes and Endocrinology. November 16, 2023.
- Sacks DB et al. Executive Summary: Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus. Diabetes Care. July 20, 2023.
- Diabetes Screenings. Medicare.
- Kosmas CE et al. The Triglyceride/High-Density Lipoprotein Cholesterol (TG/HDL-C) Ratio as a Risk Marker for Metabolic Syndrome and Cardiovascular Disease. Diagnostics (Basel). March 1, 2023.
- LDL and HDL Cholesterol and Triglycerides. Centers for Disease Control and Prevention. May 15, 2024.
- Baneu P et al. The Triglyceride/HDL Ratio as a Surrogate Biomarker for Insulin Resistance. Biomedicines. July 5, 2024.
- VLDL. Cleveland Clinic. December 5, 2022.
- Huang J-K et al. Emerging Evidence of Pathological Roles of Very-Low-Density Lipoprotein (VLDL). International Journal of Molecular Science. April 13, 2022.
- Li Y et al. Association of Remnant Cholesterol With Insulin Resistance and Type 2 Diabetes: Mediation Analyses From NHANES 1999-2020. Lipids in Health and Disease. December 18, 2024.
- Wang S et al. Association between remnant cholesterol and insulin resistance levels in patients with metabolic-associated fatty liver disease. Scientific Reports. December 5, 2022.
- ApoB: Another Look at Heart Disease Risk. American Heart Association. March 13, 2026.
- ApoB Test. Cleveland Clinic. May 16 2023.
- Soffer DE et al. Role of apolipoprotein B in the clinical management of cardiovascular risk in adults: An Expert Clinical Consensus from the National Lipid Association. Journal of Clinical Lipidology. September–October 2024.
- De Oliveira-Gomes D et al. APOLIPOPROTEIN B: Bridging the gap between evidence and clinical practice. Circulation. July 2, 2025.
- Hasan A et al. Assessment of the Relationship Between Liver Enzymes and Cardiovascular Disease: A Study in Bangladeshi Adults. Endocrinology, Diabetes & Metabolism. March 17, 2024.
- Lala V et al. Liver Function Tests. StatPearls. July 30, 2023.
- Elevated Liver Enzymes. Cleveland Clinic. May 4, 2026.
- Rosario D. How to Approach Elevated Liver Enzymes. American Association for the Study of Liver Disease. January 17, 2025.
- Koziarska-Rościszewska M et al. High-Sensitivity C-Reactive Protein Relationship with Metabolic Disorders and Cardiovascular Diseases Risk Factors. Life (Basel). July 26, 2021.
- Prioritizing Health - hsCRP: A Promising Risk Assessment Tool. American College of Cardiology. December 1, 2025.
- An hs-CRP Test can Add Clarity to Your Heart Health Picture. American Heart Association. March 13, 2026.
- C-Reactive Protein Test. Mayo Clinic.
- Assessing Cardiovascular Risk with C-Reactive Protein. Johns Hopkins Medicine.
- How to Prepare for a Lab Test. MedlinePlus. August 20, 2024.
- How to Get the Most Accurate Blood Test Results. University Hospitals. January 19, 2022.
Meet Our Experts
Natalia Johnsen, MD
Medical Reviewer
Member of American College of Lifestyle Medicine
Natalia Johnsen, MD, is a triple board-certified physician in internal medicine, lifestyle medicine, and obesity medicine, practicing as an internist and consultant at the Vancouve...
Cristina Mutchler
Author
Cristina Mutchler is an award-winning journalist with more than a decade of experience covering health and wellness content for national outlets. She previous worked at CNN, Newsy,...