Metabolic Panel Explained: Liver, Kidneys, Blood Sugar, and Cholesterol
A comprehensive metabolic panel (CMP) or basic metabolic panel (BMP) is a detailed look at how your internal organs are functioning — without a single incision. The composition of your blood reveals how your liver is working, whether your kidneys are keeping up, and whether your metabolism is on track.
The report is full of abbreviations: ALT, AST, GGT, CRP, LDL-C... This article breaks each group down in plain language — with specific normal ranges and explanations of what happens when values fall outside those ranges.
Liver Markers (ALT, AST, Bilirubin, GGT) in Plain Language
The liver is the body's main filter. When liver cells are damaged, they release enzymes into the bloodstream. Those enzymes are what we measure.
ALT (alanine aminotransferase) — the primary marker of liver cell damage.
- Normal for men: up to 56 U/L
- Normal for women: up to 45 U/L
A mild elevation (up to 2–3 times the upper limit) can occur after a fatty meal, intense exercise, certain medications, or with fatty liver disease. A significant elevation (more than 5 times the upper limit) is a reason to see a doctor promptly.
AST (aspartate aminotransferase) — found in both the liver and the heart muscle.
- Normal for men: up to 40 U/L
- Normal for women: up to 32 U/L
If AST is elevated more than ALT, it may point to a heart problem rather than a liver problem. The AST/ALT ratio helps doctors determine which organ is affected.
GGT (gamma-glutamyltransferase) — a sensitive marker of liver and bile duct stress.
- Normal for men: up to 55 U/L
- Normal for women: up to 38 U/L
GGT is very sensitive to alcohol — even moderate regular drinking raises it. It also rises with gallbladder and bile duct disease.
Bilirubin — a breakdown product of hemoglobin that the liver processes and excretes in bile.
- Total bilirubin: 0.2–1.2 mg/dL
- Direct (conjugated): up to 0.3 mg/dL
- Indirect (unconjugated): up to 0.8 mg/dL
Elevated bilirubin causes yellowing of the skin and eyes (jaundice). Causes range from hemolytic anemia to hepatitis to gallstones.
Kidney Markers (Creatinine, BUN)
The kidneys filter the blood and remove metabolic waste. When filtration is impaired, these waste products accumulate in the blood.
Creatinine — a breakdown product of muscle protein that the kidneys should be continuously removing.
- Normal for men: 0.74–1.35 mg/dL
- Normal for women: 0.59–1.04 mg/dL
Elevated creatinine signals reduced kidney function. Note: people with high muscle mass (athletes) may have slightly elevated creatinine without any pathology. Creatinine is used to calculate eGFR (estimated glomerular filtration rate) — the main measure of kidney function.
BUN (blood urea nitrogen) — a breakdown product of protein metabolism.
- Normal: 7–20 mg/dL
BUN rises with reduced kidney function, dehydration, a high-protein diet, or after intense exercise. It is always interpreted alongside creatinine.
Blood Sugar: Glucose and Hemoglobin A1c
Blood sugar is a key indicator of metabolic health. Chronically elevated sugar leads to diabetes and its complications.
Fasting glucose:
- Normal: 70–100 mg/dL
- Prediabetes: 100–125 mg/dL
- Diabetes: 126 mg/dL or higher (on two separate tests)
Glucose is a snapshot of a single moment. It fluctuates throughout the day based on food, stress, and exercise. That is why a different marker is used to diagnose diabetes definitively.
HbA1c (glycated hemoglobin) — reflects average blood sugar over the past 2–3 months. It is not affected by whether you ate before the test.
- Normal: below 5.7%
- Prediabetes: 5.7–6.4%
- Diabetes: 6.5% or above
HbA1c is the gold standard for diagnosing and monitoring diabetes.
Cholesterol: What "Good" and "Bad" Actually Mean
Cholesterol itself is essential — the body needs it to build cell membranes and produce hormones. The problem is an imbalance between its different forms.
Total cholesterol:
- Desirable: below 200 mg/dL
- Borderline high: 200–239 mg/dL
- High: 240 mg/dL or above
LDL (low-density lipoprotein) — the "bad" cholesterol. It builds up in artery walls and forms plaques that narrow blood vessels.
- Optimal for most people: below 100 mg/dL
- High cardiovascular risk: below 70 mg/dL
HDL (high-density lipoprotein) — the "good" cholesterol. It picks up cholesterol from artery walls and returns it to the liver for processing.
- Normal for men: above 40 mg/dL
- Normal for women: above 50 mg/dL
Triglycerides — fats in the blood. They rise with overeating, alcohol, and diabetes.
- Normal: below 150 mg/dL
Inflammatory Markers (CRP, Ferritin)
CRP (C-reactive protein) — the most sensitive general inflammation marker. It rises within hours of the start of any inflammatory process.
- High-sensitivity CRP (hs-CRP): below 1.0 mg/L (low cardiovascular risk)
- Standard CRP: below 5.0 mg/L
Elevated CRP indicates active inflammation, infection, or a flare of a chronic condition.
Ferritin — the protein that stores iron reserves in the body.
- Normal for men: 20–250 ng/mL
- Normal for women: 10–120 ng/mL
Low ferritin is a reliable sign of iron deficiency even when hemoglobin is still normal. High ferritin is an inflammation marker — it rises with many infections and chronic conditions.
You can interpret your metabolic panel results with AI at Symptomatica.
Frequently Asked Questions
Do I need to fast for a metabolic panel?
Yes, most metabolic panel values require 8–12 hours of fasting. This is especially important for glucose, cholesterol, and triglycerides. Water is fine. Avoid fatty food and alcohol the evening before.
My ALT is elevated — does that mean hepatitis?
Not necessarily. Mild ALT elevation can occur with fatty liver disease, certain medications (including supplements), intense exercise, and obesity. Hepatitis is one of many possible causes. A doctor makes the diagnosis after further workup.
Can I lower cholesterol without medication?
With a moderate elevation, yes. Reducing saturated fat, eliminating trans fats, increasing fiber, exercising regularly, and losing weight can lower LDL by 10–20%. With high cardiovascular risk, a doctor may prescribe medication regardless of cholesterol levels.
What is eGFR and why is it calculated?
eGFR — estimated glomerular filtration rate — shows how much blood your kidneys filter per minute. It is calculated from creatinine adjusted for age, sex, and race. Normal is above 90 mL/min/1.73m². A declining eGFR indicates reduced kidney function.
My HbA1c is 5.9% — is that diabetes?
No, 5.9% falls in the prediabetes range (5.7–6.4%). It means glucose metabolism is impaired, but diabetes has not developed yet. At this stage, lifestyle changes are highly effective: weight loss, reducing refined carbohydrates, and regular physical activity can normalize this value.
Why is ferritin more important than hemoglobin alone when checking for iron deficiency?
Iron deficiency develops in stages. Ferritin (the storage depot) drops first, then circulating iron, and finally hemoglobin. Someone can feel fatigued, experience hair loss, and have difficulty concentrating with a normal hemoglobin but depleted ferritin. Always check both.
My bilirubin is slightly above normal — what does that mean?
An isolated mild elevation in indirect bilirubin with normal liver enzymes is often Gilbert syndrome — a benign genetic variant present in 3–7% of people. It is not a disease and requires no treatment. Still worth confirming with a doctor.
Symptomatica is an informational reference service. Not a medical service; does not diagnose or prescribe treatment. For any symptoms, please consult a doctor.