Complete Longevity Biomarkers

Get tested for everything you need — and nothing you don’t. Monitor your heart, kidney, and liver health, vitamin and nutrient balance, inflammation and more to help you live longer and healthier. Felix uses the most only medically-backed biomarkers to assess your overall health and longevity. Our tests are ultra-focused to cut through the noise and give you clear, actionable insights. 

We test for everything you need — and nothing you don’t to understand your longevity. 

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Metabolic Health

• HbA1c. HbA1c measures your average blood sugar over the last 2–3 months. It helps diagnose and monitor diabetes and overall blood sugar control.
  
  
• Glucose (fasting). Fasting glucose measures blood sugar after 8 hours without food. High levels may indicate prediabetes, diabetes , or impaired glucose regulation.
  
  
• Insulin (fasting). Fasting insulin shows how much insulin your body makes to manage blood sugar. High levels often indicate insulin resistance or early metabolic issues.
  
  
• Low Density Lipoprotein (LDL) Cholesterol. Low Density Lipoprotein (LDL), often called “bad cholesterol,” carries cholesterol to your arteries. High levels can contribute to plaque buildup in arteries and increased risk of heart attack and stroke.
  
  
• Lipoprotein (a). Lipoprotein(a) is a type of LDL particle, often called "bad cholesterol.” Elevated levels are linked to an increased risk of genetic heart disease and can contribute to plaque buildup in arteries, even when other cholesterol levels are within the normal range.
  
  
• Apolipoprotein B (ApoB). Apolipoprotein B (ApoB) is a protein found in LDL particles that carry cholesterol in the blood. High levels can contribute to plaque buildup in arteries and heart disease.
  
  
• High-Density Lipoprotein (HDL) Cholesterol. High-Density Lipoprotein (HDL) cholesterol, often called “good cholesterol” removes excess cholesterol from your bloodstream. Higher levels help protect against heart disease and improve cardiovascular health.
  
  
• Cholesterol/HDL Ratio. This ratio compares total cholesterol to HDL. A higher ratio may reflect greater cardiovascular risk, while a lower ratio supports healthy heart function.
  
  
• Total Cholesterol. Total Cholesterol sums LDL, HDL, and other lipids in your blood. High total cholesterol can signal an increased risk of heart disease.
  
  
• Triglycerides. Triglycerides are fats in your blood that store energy. High levels are linked to heart disease, diabetes, and metabolic syndrome.
  
  

Kidney and Liver

• Estimated Glomerular Filtration Rate (eGFR). Estimated Glomerular Filtration Rate (eGFR) is a measure of how well your kidneys filter waste. Low values suggest reduced kidney function and may increase risk of chronic kidney disease.
  
  
• Alanine Aminotransferase (ALT). Alanine Aminotransferase (ALT) is an enzyme found in the liver that helps break down proteins. Elevated levels may indicate liver inflammation or damage, often caused by alcohol use, certain medications, or fatty liver disease.
  
  
• Alkaline Phosphatase (ALP). Alkaline Phosphatase (ALP) is an enzyme linked to liver and bone health. High or low levels can be a sign of problems with live function, bile flow — the movement of digestive fluid from the liver to the gut — or with bone turnover, which is the natural process of breaking down old bone and building new bone.
  
  
• Creatinine. Creatinine is a waste product filtered by your kidneys. High levels can indicate impaired kidney function or dehydration.
  
  
• Albumin. Albumin is a protein made by the liver that helps maintain fluid balance. Low levels can signal poor nutrition, inflammation, or liver issues.
  
  

Fatigue Hormones

• Thyroid-Stimulating Hormone (TSH). Thyroid-Stimulating Hormone (TSH) helps regulate thyroid activity. High or low levels can signal an underactive or overactive thyroid.
  
  
• Free T4. Free T4 is a thyroid hormone that helps control metabolism. High or low levels may suggest thyroid dysfunction such as hypothyroidism or hyperthyroidism.
  
  
• Total testosterone (men only). Total testosterone measures the overall level of testosterone in your blood. It plays a key role in sex drive, energy, and muscle mass.
  
  
• Free testosterone (men only). Free testosterone is the active form of testosterone that isn’t attached to proteins in your blood. It can help explain symptoms like fatigue, low sex drive, or muscle loss.
  
  

Vitamins and Nutrients

• Vitamin D. Vitamin D helps your body absorb calcium and supports immune function. Low levels are surprisingly common, especially in colder climates or among people who spend little time in the sun, and may contribute to issues like weakened bones, fatigue, or low mood.
  
  
• Vitamin B12. Vitamin B12 supports nerve health and red blood cell production. Low levels can cause fatigue, memory issues, or numbness.
  
  
• Ferritin. Iron (ferritin) is a measure of your body’s stored iron. Low levels may indicate iron deficiency, while high levels can suggest inflammation or excess iron in the body (a condition known as iron overload).
  
  

Inflammation / Immune / Blood Cells

• C-Reactive Protein (CRP). C-Reactive Protein (CRP) is a marker of inflammation in the body. Elevated levels can suggest infection, chronic disease, or increased risk of heart issues.
  
  
• Erythrocyte Sedimentation Rate (ESR). Erythrocyte Sedimentation Rate (ESR) is another marker of inflammation in the body. High levels can signal inflammation from infection, autoimmune disease, or chronic illness.
  
  
• Neutrophils. Neutrophils are your body’s first defense against infection. High or low levels may indicate acute infection, inflammation, or an immune imbalance.
  
  
• Monocytes. Monocytes support immune defense and tissue repair. Elevated levels may reflect chronic inflammation, which can accelerate aging and decrease longevity.
  
  
• White Blood Cell Count (WBC). White Blood Cell Count (WBC) measures the number of immune cells in your blood. Levels that are too high or too low may signal infection, inflammation, or immune system issues that could impact long-term health.
  
  
• Lymphocytes / Lymphocyte Percentage. Lymphocytes help fight viruses and regulate immunity. Imbalances can reflect immune stress, chronic infection, or inflammation.
  
  
• Eosinophils. Eosinophils are involved in defense against allergens and parasites. High levels can signal allergies, asthma, or immune system dysregulation.
  
  
• Basophils. Basophils are immune cells that help trigger allergic reactions and inflammation by releasing substances like histamine. High or low counts may point to immune system dysregulation or chronic allergy.
  
  
• Hemoglobin (HB) (HGB). Hemoglobin (HGB) carries oxygen in red blood cells. Low levels may indicate anemia or nutrient deficiencies that can impact energy and resilience.
  
  
• Mean Corpuscular Hemoglobin (MCH). Mean Corpuscular Hemoglobin (MCH) measures the average amount (mass) of hemoglobin per red cell. High or low levels may point to different types of anemia that affect how well your blood carries oxygen.
  
  
• Mean Corpuscular Hemoglobin Concentration (MCHC). Mean Corpuscular Hemoglobin Concentration (MCHC) measures the concentration of hemoglobin within red blood cells — i.e., how “full” each cell is with hemoglobin, relative to its size. Low values can indicate iron deficiency; elevated values may suggest other blood disorders.
  
  
• Mean Corpuscular Volume (MCV) / Mean cell volume. Mean Corpuscular Volume (MCV) measures the average size (volume) of red blood cells. High or low levels may signal anemia related to vitamin B12, folate, or iron deficiency.
  
  
• Platelet Count. Platelets help with blood clotting. High or low counts can affect healing, increase bleeding or clotting risk, or reflect underlying inflammation or disease.
  
  
• Red Blood Cell Count (RBC). Red Blood Cell Count (RBC) measures the number of red blood cells in your blood. Low levels may signal anemia, while high levels can thicken the blood and strain the heart and blood vessels.
  
  
• Red Cell Distribution Width (RDW). Red Cell Distribution Width (RDW) measures the variation in red blood cell size. High values can signal nutritional deficiencies, inflammation, or aging-related blood changes.

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