CBC (Complete Blood Count) Test
A complete blood count, or CBC, is one of the most common blood tests. It gives a broad picture of the cells that make up blood — red cells, white cells, and platelets — which clinicians use to help evaluate overall health.
About this test
The CBC is a grouped panel rather than a single measurement. It looks at the main types of cells circulating in the bloodstream and reports on several features of each.
Within those broad categories, the panel groups a number of related measurements. For red cells, it describes how many there are and characteristics such as their size and hemoglobin content.
Who might consider this test?
- Some are following up on general symptoms such as fatigue, weakness, or feeling run down, which can be linked to the red-cell side of the count.
- Because it is broad and widely used, the CBC often appears alongside other panels when someone wants a general overview of how their body is doing.
Test details
| Quest code | 6399 |
|---|---|
| Methodology | Electronic Cell Sizing/Counting/Cytometry/Microscopy |
| Sample type | Whole blood |
| Collection | Quest patient service center |
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Additional details
What a CBC groups together
The value of a CBC is in its breadth. Rather than isolating one marker, it gathers a family of related measurements about red cells, white cells, and platelets and presents them side by side. This lets a clinician look at how the different components relate to one another, which can be more informative than any single figure viewed alone.
Each family answers a different kind of question. The red-cell measurements relate to how well oxygen is being carried, the white-cell measurements relate to immune activity, and the platelet measurement relates to the blood's clotting machinery. Grouping them means one blood draw can inform several lines of thought at once.
Why clinicians often order it
Because it surveys so much in a single test, the CBC is one of the first panels many clinicians reach for when they want a general sense of what is happening. It is broad by design, which makes it useful as an orienting step: the pattern it shows can help a clinician decide whether a closer, more focused look at any one area is worth considering.
The CBC is also familiar and routine, which is part of why it appears so often in general check-ups. It measures the cellular building blocks of blood rather than making any conclusion on its own, and the results are always meant to be weighed by a clinician in the full context of a person's situation.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does a CBC test measure?
A complete blood count surveys the main cells in blood — red cells, white cells, and platelets — and reports several features of each. It is a grouped panel that gives a broad snapshot rather than a single number.
Why do clinicians order a CBC so often?
Because it covers several systems in one draw, the CBC is a useful general starting point. The pattern it shows can help a clinician decide whether any one area is worth a closer look.
How is the sample collected?
Through a routine blood draw at a Quest patient service center. A phlebotomist takes a small sample from a vein in the arm and sends it to the laboratory.
Do I need to fast before a CBC?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Can a CBC tell me what is wrong on its own?
No. A CBC measures the cellular components of blood, but it does not make a conclusion by itself. A clinician interprets the full pattern alongside symptoms, history, and any other markers.
What does a CBC test cost without insurance?
$15. Celio Health's price is a flat cash price and insurance is never billed: the required physician's order is included.