Lab basics

Understanding your blood test results: a simple guide

Learn to read and understand common blood test results including CBC, metabolic panel, and more. Know what your numbers mean.

By Arhaan Delawalla, founder · Not reviewed by a clinician · Updated · 2 min read

Overview

Blood tests are among the most common medical tests. Understanding your results helps you have informed conversations with your doctor and take charge of your health.

Complete blood count (CBC)

What it measures

  • White blood cells (WBC): Fight infection. Normal: 4,500-11,000/mcL
  • Red blood cells (RBC): Carry oxygen. Normal varies by sex
  • Hemoglobin: Oxygen-carrying protein. Normal: 12-17.5 g/dL
  • Hematocrit: Percentage of blood that is red cells. Normal: 36-52%
  • Platelets: Help blood clot. Normal: 150,000-400,000/mcL

What abnormal results may mean

  • High WBC: infection, inflammation, or stress
  • Low WBC: immune deficiency or medication effects
  • Low hemoglobin: anemia
  • Low platelets: bleeding risk

Comprehensive metabolic panel (CMP)

Key values

  • Glucose: Blood sugar. Fasting normal: 70-100 mg/dL
  • BUN/Creatinine: Kidney function markers
  • Electrolytes: Sodium, potassium, chloride, CO2 balance
  • Liver enzymes (ALT/AST): Liver health indicators
  • Albumin: Protein and nutrition status

Lipid panel

  • Total cholesterol: Desirable: under 200 mg/dL
  • LDL ("bad"): Optimal: under 100 mg/dL
  • HDL ("good"): Higher is better; aim for 60+ mg/dL
  • Triglycerides: Normal: under 150 mg/dL

Tips for understanding your results

  1. Look at the reference range: each lab provides normal ranges
  2. One abnormal value isn't always concerning: trends matter more
  3. Context matters: fasting status, medications, and hydration affect results
  4. Ask your doctor: don't self-assess from lab results
  5. Track over time: compare with previous results

Your blood test results are one piece of your health picture. Always discuss results with your healthcare provider.

Common questions

What does a CBC test for?

A Complete Blood Count measures white blood cells, red blood cells, hemoglobin, hematocrit, and platelets to evaluate overall health and detect disorders like anemia and infection.

Do I need to fast before a blood test?

It depends on the test. Lipid panels and glucose tests typically require 8-12 hours of fasting. Your doctor will specify if fasting is needed.

What if one value is slightly out of range?

A single slightly abnormal value isn't necessarily concerning. Trends over time and your overall clinical picture matter more. Discuss with your doctor.

Sources and further reading

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