Complete Guide to Metabolic & Blood Test Panels: What Your Numbers Mean

This page is now the complete blood test guide for understanding common metabolic and longevity lab panels and what your numbers mean.

When you open your results, focus on four things for each marker:

• The test name (what was measured)

• Your result

• The lab reference range (what is common in the lab’s population)

• The trend (how your result is changing over time)

A reference range is not the same as an “optimal” range. A result slightly outside the reference range is often a prompt for context and follow-up, not a diagnosis by itself.

• Fasting status: Many markers are sensitive to recent food or drink.

• Recent hard exercise (24–48h): Can raise AST and creatinine.

• Dehydration: Can concentrate several values and change BUN/creatinine.

• Alcohol (24–72h): Can affect triglycerides and liver enzymes.

• Medications and supplements: Especially biotin, thyroid meds, statins, diabetes meds, and certain supplements.

If you only learn a few panels, start here. These are the workhorses that show up in routine preventive care.

A CMP is a group of blood chemistry tests that gives a high-level snapshot of:

• Kidney function

• Electrolyte and acid-base balance

• Liver health

• Blood sugar and protein status

A BMP is the smaller cousin of a CMP. It typically includes kidney markers, electrolytes, and glucose, but does not include the expanded liver and protein markers.

A CBC helps assess:

• Red blood cells (oxygen delivery)

• White blood cells (immune activity)

• Platelets (clotting)

If symptoms like unexplained fatigue, frequent infections, or easy bruising are present, the CBC is often one of the first panels to revisit.

A typical lipid panel includes:

• LDL-C

• HDL-C

• Triglycerides

• Total cholesterol

Many clinicians also use derived ratios (like triglycerides/HDL) as additional metabolic context.

These tests help interpret why glucose and lipids look the way they do, and they often shift the plan from reactive to preventive.

A fasting insulin test measures how much insulin is circulating after an overnight fast.

Why it matters:

• Fasting glucose can stay “normal” for years while insulin rises.

• Elevated fasting insulin can be an earlier sign of metabolic strain.

Many lab reference ranges are broad. From a preventive perspective, it can help to think in tiers:

• Optimal: < 5 µU/mL

• Early concern: 5–10 µU/mL

• Concerning: 10–20 µU/mL

• High risk: > 20 µU/mL

HOMA-IR combines fasting insulin and fasting glucose.

• Formula (mg/dL version): (Fasting insulin × Fasting glucose) / 405

• Many clinicians aim for HOMA-IR < 1.5 as a rough “better insulin sensitivity” target.

HbA1c shows average glycemic exposure over the last ~8–12 weeks. It is less sensitive to day-to-day variability than a single fasting glucose.

C-peptide can help distinguish between high insulin due to overproduction vs other causes, since it is produced in a 1:1 ratio with endogenous insulin.

For many metabolic tests, fast 8–12 hours. During the fast:

• Drink plain water.

• Avoid coffee, sweeteners, and supplements unless your clinician instructs otherwise.

• Avoid intense workouts.

• Avoid heavy alcohol.

• Aim for solid sleep.

Do not stop prescribed medication without clinician guidance. Instead, document what was taken and when.

The most useful interpretation is usually pattern-based.

It depends on goals and risk factors. Many people use annual testing as a baseline, and more frequent re-checks (for example every 3–6 months) when actively changing lifestyle or monitoring a known issue.

Treat it as a signal to add context and look for a trend. Many clinicians will re-test to confirm.

These pages are now incorporated here (and should 301 redirect to this guide):

• Fasting insulin: /blog/fasting-insulin-test

• Reading lab results: /blog/how-to-read-blood-work-results

• Longevity blood testing: /blog/blood-test-for-longevity