How to Read Your Blood Test Results

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You got your lab results back. Now you are staring at a page of numbers, abbreviations, and reference ranges with no idea what any of it means. This guide breaks down the most common tests.

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Printable chart with common markers, reference ranges, and what to ask your doctor.

Common markers
Reference ranges
Doctor discussion prompts

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How to read the report

A lab report is a comparison tool: it compares your result to a population range and flags values outside that range. It does not automatically explain why a value is high or low, and it does not always show whether a value is optimal for your goals.

Test name: The marker being measured.
Your result: The value from your sample.
Reference range: The normal range for that lab.
Flag: H for high, L for low, or blank if normal.

Reference ranges vary between labs. Always compare your result to the specific reference range shown on your report.

Complete blood count (CBC)

WBC: White blood cells for immune function. Typical range: 4,000-11,000 cells/uL.
RBC: Red blood cells for oxygen carrying. Typical range: 4.5-5.5 million cells/uL for men and 4.0-5.0 for women.
Hemoglobin: Oxygen-carrying protein. Typical range: 13.5-17.5 g/dL for men and 12.0-16.0 for women.
Hematocrit: Percentage of blood that is red cells. Typical range: 38-50% for men and 36-44% for women.
MCV: Red blood cell size. Typical range: 80-100 fL.
Platelets: Clotting cells. Typical range: 150,000-400,000 cells/uL.

Common findings include low hemoglobin or RBC suggesting anemia, high WBC suggesting infection or inflammation, and low platelets suggesting bleeding risk.

Comprehensive metabolic panel (CMP)

Glucose: Blood sugar. Typical fasting range: 70-100 mg/dL.
BUN and creatinine: Kidney-related markers. Typical ranges: BUN 7-20 mg/dL, creatinine 0.7-1.3 mg/dL.
eGFR: Kidney filtration rate. Typical result is greater than 60 mL/min.
Sodium and potassium: Electrolyte balance. Typical ranges: sodium 136-145 mEq/L, potassium 3.5-5.0 mEq/L.
Calcium: Bone and nerve function. Typical range: 8.5-10.5 mg/dL.
ALT, AST, ALP, bilirubin, albumin: Liver function and protein markers. Abnormal patterns can suggest liver stress, bone issues, or other causes.

Lipid panel

Total cholesterol: All cholesterol. Optimal is usually under 200 mg/dL.
LDL: Bad cholesterol. Optimal is often under 100 mg/dL, lower for higher-risk people.
HDL: Good cholesterol. Higher is better; common targets are over 40 mg/dL for men and over 50 for women.
Triglycerides: Blood fats. Optimal is usually under 150 mg/dL.
Useful ratios: Triglyceride/HDL under 2 is good, under 1 is excellent. Total cholesterol/HDL under 5 is preferred, ideally under 3.5.

Thyroid panel

TSH: Thyroid-stimulating hormone. Typical range: 0.4-4.0 mIU/L.
Free T4: Active thyroid hormone. Typical range: 0.8-1.8 ng/dL.
Free T3: Most active thyroid form. Typical range: 2.3-4.2 pg/mL.

High TSH with low T4 can suggest hypothyroid. Low TSH with high T4 can suggest hyperthyroid. High TSH with normal T4 can suggest subclinical hypothyroid.

Inflammation markers

Inflammation markers are nonspecific. They can rise from infection, injury, autoimmune activity, metabolic issues, or other stressors, so they are most useful when interpreted with symptoms, other labs, and repeat testing.

hs-CRP: General inflammation. Optimal is often under 1.0 mg/L.
ESR: Sedimentation rate. Typical range is 0-20 mm/hr.
Homocysteine: Cardiovascular inflammation marker. Optimal is often under 10 umol/L.

Vitamin and mineral levels

Vitamin and mineral markers help explain symptoms that can look like hormone, thyroid, or mood problems. Low iron stores, low B12, or low vitamin D can contribute to fatigue and poor resilience even when larger panels look normal.

Vitamin D (25-OH): Vitamin D status. Common optimization target: 40-60 ng/mL.
Vitamin B12: B12 status. Common target: 400-800 pg/mL.
Ferritin: Iron stores. Common target: 50-150 ng/mL.
Iron: Circulating iron. Typical range: 60-170 ug/dL.

What normal actually means

Reference ranges are based on broad populations, and 5% of healthy people may fall outside the normal range. Lab variation, individual baseline, time of day, and fasting status all matter.

One out-of-range value does not automatically mean disease. Look at patterns across multiple tests and over time.

When to be concerned

The goal is not to panic over every flag. The goal is to notice meaningful patterns: related markers moving together, values far outside range, changes over time, or lab findings that match how you feel.

Multiple related markers are abnormal.
A marker is significantly outside the range.
A marker is trending in the wrong direction over time.
You have symptoms that match the abnormality.

Next steps

1 Review your results using this guide.
2 Note values outside the reference range.
3 Look for patterns across related markers.
4 Discuss findings with your doctor.
5 Consider follow-up testing if needed.

Last updated June 16, 2026

Frequently asked questions

Why are my results different from the last test?

Lab values naturally fluctuate. Hydration, time of day, fasting status, recent exercise, and minor illness can affect results. Compare trends over months, not single tests.

What does borderline mean?

It means your result is at the edge of the reference range. It may warrant monitoring but does not necessarily require treatment.

Can I order my own lab tests?

Yes. Direct-to-consumer lab testing lets you order blood work without a doctor visit in many cases.

How often should I get blood work?

For general health screening, annually is typical. If you are monitoring a condition or optimizing health, every 3-6 months may be appropriate.

Do I need to fast for blood work?

For glucose and lipid panels, usually yes for 8-12 hours. Many other tests do not require fasting, but check the lab instructions.