What is the difference between a CBC and a CBC with differential?

A basic CBC counts red cells, white cells, hemoglobin, hematocrit, and platelets. The 'with differential' version also breaks white cells into their five types (neutrophils, lymphocytes, monocytes, eosinophils, basophils), which helps tell infection types apart and flags some blood conditions. The basic CBC is cheaper if you do not need the breakdown.

Should I get a CBC or a ferritin test for suspected iron deficiency?

Both have a role. A CBC shows whether anemia is already present, but ferritin drops first and catches iron deficiency before the CBC changes. If fatigue and low iron are the concern, ferritin (often with iron and TIBC) is the more sensitive early test.

Do I need to fast for a CBC?

No fasting is required for a CBC with differential. You can be drawn at any time of day. If you are bundling it with a fasting test like glucose or a lipid panel, follow the fasting rule for those.

Is a CBC with Differential worth it?

What it costs, whether to test at home or at Quest or Labcorp, and how to read your results - reviewed and updated June 2026.

The short answer

Yes for a broad baseline. A CBC with differential is the most-ordered blood test in medicine - it screens for anemia, infection, and clotting problems at once, and pairs perfectly with a CMP for a complete routine workup.

$21.99 at TestWellResults in 1–3 business daysNo doctor's visit neededCPT 85025

Who should order it (and who can wait)

Worth it if you...

•Anyone getting an annual physical or a general health baseline
•Fatigue, weakness, or shortness of breath that could be anemia
•Frequent or lingering infections, easy bruising, or unusual bleeding
•Monitoring while on medications that affect blood counts

You can probably wait if you...

•You only need iron status - a ferritin test is a more sensitive early marker of iron deficiency
•You had a normal CBC recently with no new symptoms

We would rather you order the right test than the most expensive one.

At-home vs Quest vs Labcorp

The most common question we get. The short version: the lab and the result are the same - you are choosing where the blood is drawn.

Walk into a lab

Get drawn at any Quest or Labcorp location - thousands nationwide, often same-day. Best for speed and lowest cost.

At-home draw

A mobile phlebotomist comes to you, where available. Same venous sample, drawn at your kitchen table.

Same result

Whichever you pick, it is run on the same CLIA-certified analyzers with the same reference ranges.

A CBC requires a whole-blood venous sample, so it is drawn at Quest or Labcorp, or by an at-home mobile phlebotomist where available - not a fingerstick kit. No fasting needed.

How to read your results

The markers that matter most and what an out-of-range value can mean. Reference ranges vary by lab, age, and sex.

Marker	Typical range	What it means
Hemoglobin	13.5-17.5 (men) / 12.0-15.5 (women) g/dL	Low hemoglobin defines anemia; high can reflect dehydration or, less often, a marrow condition.
White blood cells (WBC)	4.5-11.0 x10^9/L	High often signals infection or inflammation; low can point to viral illness or marrow/immune issues.
Platelets	150-450 x10^9/L	Low raises bleeding risk; high can accompany inflammation or clotting tendencies.
Differential (neutrophils vs lymphocytes)	Report as % / absolute	The mix helps distinguish bacterial (neutrophil-heavy) from viral (lymphocyte-heavy) patterns.

Frequently asked questions

Ready to order your CBC with Differential?

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About this guide

Reviewed June 20, 2026. This is general health information, not medical advice, diagnosis, or treatment. Reference ranges vary by laboratory, age, sex, and clinical context - always interpret results with a qualified healthcare provider. Lab analysis is performed at CLIA-certified Quest Diagnostics and Labcorp facilities.