Panel: several blood-cell measurements · Blood counts
Complete blood count (CBC)
Understand what a blood count includes—and what it leaves out.
Factual and editorial verification: October 21, 2026. No independent clinical review has been performed. This guide is educational, not personal medical advice.
Direct answer
A CBC measures blood cells and related features. A CBC with differential also breaks down the types of white blood cells. Neither name, on its own, means ferritin or serum iron is included. [1] [2]
What does a CBC measure?
A CBC is a group of measurements, not one number. It checks blood cells and related features. Typical results include: [1]
- Red blood cells: cells that carry oxygen.
- Hemoglobin: the oxygen-carrying protein in red cells.
- Hematocrit: the share of blood made up of red cells.
- Mean corpuscular volume (MCV): the average size of red cells.
- White blood cells: cells involved in immune defense.
- Platelets: cell fragments that help blood clot. [2]
Why might a clinician order it?
A clinician may use a CBC during a checkup or to help assess anemia, infection, or changes during treatment. It helps guide follow-up, but does not name a disease by itself. [1]
Does every CBC include a differential?
No. A CBC with differential adds a breakdown of white blood cell types. A CBC without differential does not include that same breakdown. Read the exact order, rather than relying on the word CBC alone. [1]
| Feature | CBC without differential | CBC with differential |
|---|---|---|
| Red cells, hemoglobin, hematocrit, and platelets | Included in a standard CBC | Included in a standard CBC |
| Total white-cell count | Included | Included |
| Breakdown of white-cell types | Not included as a differential | Included; check whether counts, percentages, or both are reported [3] |
| Ferritin and serum iron | Not part of the standard CBC | Not part of the standard CBC |
Bundles can add tests. A manual smear review or other follow-up may be conditional, so do not infer it from the name alone. [1]
How should I prepare?
A CBC alone usually needs no special preparation. Other tests collected at the same visit may require fasting or other steps. Confirm the instructions for the whole order. [1]
Bring your medicine list and let the clinician know about relevant health changes. Do not stop treatment to prepare on your own.
What happens at the lab?
A health professional usually takes blood from a vein in your arm. A brief sting or small bruise is possible. [1]
What can and cannot it tell me?
A flagged result has many possible explanations. The pattern across results, your history, and sometimes other tests matter. Compare your results with the ranges on your own report and discuss them with the clinician. [2]
A CBC does not directly measure ferritin, serum iron, blood sugar, or cholesterol. A report with many rows is not a complete check of every part of your health.
Questions that help compare orders
- Does this CBC include a differential?
- Are extra blood-cell tests conditional or separately ordered?
- If iron stores are the question, is ferritin actually on the order?
- Who will review any flagged results?
References and editorial verification
Factual and editorial verification completed October 21, 2026 against the specific references below. Prepared by OrderMyOwnLabs using AI-assisted research and fact-checking. No independent clinical review or medical certification is claimed.
- MedlinePlus: Complete blood count
- NHLBI: Blood tests
- MedlinePlus: Blood Differential — white-cell types and reporting
Provider-specific source: Ulta’s exact product listing (affiliate link). We may earn a commission at no additional cost to you. Affiliate Disclosure. Checked October 21, 2026; no checkout or commission attribution test.
Editorial scope: test identity, uses, preparation, limitations, and comparisons checked against these references. Individual diagnosis, treatment targets, and interpretation remain the responsibility of a qualified healthcare professional.
Medical Disclaimer
OrderMyOwnLabs.com is an independent educational and referral website, not a medical provider or laboratory. This article is for general informational purposes only and does not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional about which tests are appropriate for you and how to interpret your results. Testing services, prices, availability, and ordering requirements are determined by independent third-party providers.