Metabolic Health

Hemoglobin A1c (HbA1c) reflects average blood glucose levels over the preceding 2-3 months by measuring the percentage of hemoglobin protein in red blood cells that has glucose attached (glycated). It's a key marker for diagnosing and monitoring diabetes risk. While valuable, HbA1c is an average and doesn't capture glucose variability or spikes; Continuous Glucose Monitoring (CGM) provides a more comprehensive view of glycemic control. Standard Interpretation:

• < 5.7%: Normal
• 5.7% - 6.4%: Prediabetes
• ≥ 6.5%: Diabetes For optimal health and minimizing glycation-related damage associated with aging, longevity experts often target levels below the prediabetes threshold, ideally <5.5% or even <5.3%.

Uric Acid is a waste product formed from the breakdown of purines (found in DNA and certain foods/drinks like alcohol, red meat, fructose). Elevated levels (hyperuricemia) can lead to gout (crystal deposition in joints) and kidney stones. High uric acid is also increasingly recognized as a marker and potential contributor to metabolic syndrome, insulin resistance, hypertension, and cardiovascular disease.

Serum Albumin is the most abundant protein in the blood, synthesized by the liver. It maintains oncotic pressure (keeping fluid in blood vessels), transports hormones, fatty acids, and drugs, and acts as an antioxidant and anti-inflammatory mediator. Low levels can indicate liver disease, kidney disease (loss in urine), malnutrition, chronic inflammation, or infection (negative acute phase reactant). High levels usually suggest dehydration.

Serum Creatinine is a waste product generated from muscle metabolism (creatine breakdown). It is filtered out of the blood by the kidneys, so blood levels are a key indicator of kidney filtration function when considered alongside factors like age, sex, race, and muscle mass. Higher levels generally indicate poorer kidney function. Use eGFR (Estimated Glomerular Filtration Rate) calculated from Creatinine for a better assessment of kidney function.

Serum Potassium is the primary intracellular cation, essential for nerve conduction, muscle contraction (especially the heart), and fluid balance. Serum levels are kept within a narrow range, primarily regulated by the kidneys. Abnormal levels (hypokalemia or hyperkalemia) can cause serious cardiac arrhythmias and muscle weakness, resulting from kidney disease, medications (diuretics, ACE inhibitors), hormonal issues, or severe fluid loss.

Total Protein measures the combined concentration of all proteins in the blood serum, primarily albumin and globulins. It provides a general indication of nutritional status, liver function (protein synthesis), kidney function (protein loss), and hydration. Abnormal levels usually prompt investigation of specific protein fractions (albumin, globulin types).

Serum Sodium is the main cation in extracellular fluid and crucial for maintaining fluid balance, nerve impulse transmission, and muscle function. Levels are tightly regulated by the kidneys and hormones. Abnormal levels (hyponatremia or hypernatremia) usually reflect disturbances in water balance rather than sodium intake, often related to kidney function, hormonal issues (like ADH), or excessive fluid loss/gain.

Alkaline Phosphatase (ALP) is an enzyme found primarily in the liver (bile ducts), bone, intestines, and placenta. Elevated levels can indicate liver disease (especially cholestatic conditions affecting bile flow), bone disorders with increased bone turnover (e.g., Paget's disease, fractures, growing children, vitamin D deficiency), or, rarely, other causes. Isoenzyme testing can help determine the source (liver vs. bone).

Serum Chloride is the major anion in extracellular fluid, working with sodium to maintain fluid balance and acid-base status. Levels often mirror sodium levels. Abnormal chloride levels can result from dehydration, kidney disease, excessive vomiting or diarrhea, or acid-base disturbances (like metabolic acidosis or alkalosis).

Total Carbon Dioxide (CO2) content in serum primarily reflects the level of bicarbonate (HCO3-), a major component of the body's acid-base buffering system managed by the kidneys and lungs. Abnormal levels indicate acid-base imbalances: low levels suggest metabolic acidosis or respiratory alkalosis, while high levels suggest metabolic alkalosis or respiratory acidosis.

Serum Globulin is a calculated value (Total Protein - Albumin) representing a diverse group of proteins, including immunoglobulins (antibodies) and carrier proteins. Elevated globulins can indicate chronic inflammation, infection, autoimmune diseases, or certain blood cancers (like multiple myeloma). Low levels are less common but might occur with immunodeficiency or protein loss. The Albumin/Globulin ratio (A/G Ratio) is often considered, with optimal > 1.5.

Serum Calcium measures the total amount of calcium (bound to albumin and free/ionized) in the blood. Calcium is essential for bone health, muscle contraction, nerve signaling, and blood clotting. Levels are tightly regulated by parathyroid hormone (PTH) and vitamin D. Abnormal levels can indicate issues with the parathyroid glands, vitamin D status, kidney function, or certain cancers. Ionized calcium is the biologically active form and may be more accurate if albumin is abnormal.

Total Bilirubin measures the sum of direct (conjugated) and indirect (unconjugated) bilirubin in the blood. Bilirubin is a yellowish pigment produced from the breakdown of heme (mostly from red blood cells). Elevated levels cause jaundice (yellowing of skin/eyes) and can indicate liver disease (impaired conjugation/excretion), bile duct obstruction, or increased RBC breakdown (hemolysis). Gilbert's syndrome is a common, benign cause of mild unconjugated hyperbilirubinemia.

Aspartate Aminotransferase (AST) is an enzyme found primarily in the liver, heart, skeletal muscle, and kidneys. Elevated serum AST levels often indicate liver cell damage (hepatitis, toxins, ischemia) but can also rise due to muscle injury (including heart attack) or hemolysis. Its interpretation requires context, often alongside ALT (ALT is more liver-specific).

Blood Urea Nitrogen (BUN) measures the amount of nitrogen in the blood that comes from urea, a waste product formed in the liver from protein metabolism and excreted by the kidneys. Elevated BUN can indicate decreased kidney function, dehydration, high protein intake, or gastrointestinal bleeding. Low BUN is less common but can occur with liver disease or malnutrition. Often interpreted alongside creatinine (BUN/Creatinine ratio).

Fasting Glucose measures blood sugar levels after an overnight fast (typically 8-12 hours). It reflects baseline glucose regulation. While standard guidelines define diabetes risk based on thresholds (e.g., prediabetes 100-125 mg/dL, diabetes ≥126 mg/dL), longevity experts emphasize maintaining levels in a tighter, lower optimal range (e.g., 70-90 mg/dL) for better metabolic health, reduced glycation, and potentially lower risk of age-related diseases. Continuous Glucose Monitoring (CGM) provides much richer data on glucose variability and post-meal responses.

Albumin/Globulin Ratio is a calculated value (Albumin / Globulin) representing the ratio of albumin to globulin in the blood. It is often used to assess liver function and inflammation.

Alanine Aminotransferase (ALT) is an enzyme found predominantly in liver cells. Elevated serum ALT is a more specific indicator of liver cell injury or inflammation (hepatitis, fatty liver disease, drug toxicity) than AST. Consistently maintaining ALT in the lower end of the reference range is associated with better liver health.

Cystatin C is a protein produced by most cells in the body and filtered by the kidneys at a constant rate. Unlike creatinine, its levels are less affected by muscle mass or diet, making it potentially a more sensitive marker of early kidney dysfunction, especially when creatinine-based eGFR is borderline or muscle mass is atypical. Elevated levels indicate reduced glomerular filtration rate. Use eGFR calculated from Cystatin C (eGFRcys) or combined Creatinine-Cystatin C (eGFRcr-cys) for the best assessment of kidney function.

Fasting Insulin measures the level of insulin hormone after an overnight fast. Insulin regulates blood glucose uptake into cells. Elevated fasting insulin (hyperinsulinemia) is an early sign of insulin resistance, often preceding elevations in glucose or HbA1c. Maintaining low fasting insulin levels is crucial for metabolic health and longevity. Note: Results are highly unreliable if not measured in a truly fasted state (8-12 hours).