Complete Blood Count (CBC)
Counts red blood cells, white blood cells, and platelets from one blood draw. One of the most ordered tests in all of medicine.
Blood runs three separate cell lines, and each one does a different job. A CBC counts all of them: how many red cells are moving oxygen, how many white cells are on patrol, and whether platelets can still seal a wound. Doctors reach for this test constantly because one number landing outside range can open investigations for anemia, infection, leukemia, clotting disorders, and more. The result narrows the field; it tells a doctor exactly where to look next.
Self-Pay Price Comparison
| Provider | Price | vs. Highest | Order |
|---|---|---|---|
Quest QuestHealth self-pay | $29.00 | Highest | Order · Quest |
LabCorp Labcorp OnDemand | $29.00 | Highest | Order · LabCorp |
GoodLabs Discount lab network | $3.00Best value | Best price | Order · GoodLabs |
What This Test Measures
The CBC reports values across all three cell lines. Here are the eight that carry the most diagnostic weight:
Counts all white cells in a microliter of blood; high points to infection or inflammation, low points to immune suppression or marrow failure.
Counts oxygen-carrying cells; low is the primary indicator of anemia, high suggests dehydration or a rare overproduction condition.
The oxygen-binding protein packed inside red cells; most doctors look here first when fatigue or pallor raises anemia as a possibility.
Fraction of total blood volume made up of red cells; it tracks closely with hemoglobin and drops with anemia, climbs with dehydration.
Tiny clotting cells that seal bleeding; low counts raise bruising and hemorrhage risk, high counts can point toward inflammation or marrow abnormality.
Average red cell size; small cells are the signature of iron deficiency, large cells point toward B12 or folate deficiency.
The white cells that mount the first defense against bacteria; high neutrophil count alongside elevated WBC typically means bacterial illness.
White cells built to coordinate the viral immune response; elevated counts usually point toward viral infection or certain lymphoproliferative conditions.
How to Read Your Results
Your results come back with a reference range for every value. Here is what the four most common flags actually mean:
| Marker | Normal Range | If Flagged | What It Might Mean |
|---|---|---|---|
| Hemoglobin | Male: 13-18 gm/dL; Female: 12-16 gm/dL (MedlinePlus Medical Encyclopedia, CBC). | low | Iron deficiency, B12 or folate deficiency, blood loss, or chronic disease are the most common causes. Add ferritin and B12 to confirm which direction to chase. |
| WBC count | 4,500-11,000 cells/mcL (MedlinePlus Medical Encyclopedia, CBC). | high | Infection, inflammation, steroids, and physical stress are the usual drivers. A severely elevated count or a markedly shifted differential is what prompts urgent follow-up. |
| Platelet count | 150,000-400,000/dL (MedlinePlus Medical Encyclopedia, CBC). | low | Viral illness, immune platelet destruction, drug effects, or marrow suppression all bring counts down. Below 50,000, bleeding risk becomes real and same-week follow-up is standard. |
| MCV | 80-100 femtoliters (MedlinePlus Medical Encyclopedia, CBC). | low | Small red cells are the hallmark of iron deficiency anemia. Pair the result with ferritin and hemoglobin to confirm and gauge how depleted the stores are. |
When to Order
Annual baseline
A CBC every one to two years is standard preventive care for adults. Slow-developing anemia and immune shifts rarely cause symptoms until a blood test catches them.
Fatigue, weakness, or shortness of breath
These three are the textbook presentation of anemia. A CBC tells you in one draw whether low hemoglobin or a low red cell count is behind them.
Fever or recurring infections
The WBC count and differential tell your doctor whether the immune system is over-responding, under-responding, or signaling something in the marrow.
Starting a medication that affects blood
Steroids, chemotherapy, immunosuppressants, and certain blood pressure drugs all shift cell counts. A pre-treatment CBC gives you a clean reference point.
Monitoring a diagnosed blood condition
Anemia, leukemia, blood disorders, and post-chemo recovery all require serial CBCs to track whether the trend is heading the right direction.
Prep & Logistics
- Fasting
- Typically no fasting
- Sample
- Blood draw from a standard arm vein
- Results
- Usually 24-48 hours; most portals post results the same day or the next.
- Referral
- Often self-order (check local rules)
- Markers
- 15+ values. Order CBC with differential - it breaks white cells into subtypes. Without differential you only get the total count, which is far less useful.
Tests That Pair With This One
Confirms iron deficiency when Hgb or MCV is low and the cause is still unclear.
Rules out B12 deficiency anemia when MCV is elevated and diet or absorption is a factor.
Adds kidney, liver, and metabolic context when blood count changes need a broader explanation.
Tells you whether the bone marrow is actively responding to anemia or staying quiet.
FAQ
I feel fine—do I still need a CBC on a routine checkup?
For many adults it is still the fastest screen for anemia, infection, and platelet problems before symptoms show. If everything has been normal for years and you are low risk, your clinician may space draws out—but skipping blood counts entirely is a conscious trade, not a default.
My WBC came back high. Should I be worried?
Probably not if it is mild. A slightly elevated WBC shows up with colds, stress, hard training, and even poor sleep. What matters is how high it is, how the differential looks, and whether it normalizes on a repeat draw. Share it with a doctor who knows your recent history.
What is the difference between a CBC and a CBC with differential?
A CBC gives you the total white blood cell count. A CBC with differential breaks that number into subtypes: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. The differential is what makes the result useful. All three providers listed here include it.
How often should I get a CBC?
For healthy adults with no symptoms, every one to two years as part of a general check-in is reasonable. More often if you are managing anemia, taking a drug that shifts blood counts, or tracking a result that came back outside range.
Sources
Prices pulled directly from provider websites and verified by hand. Reference ranges sourced from MedlinePlus. Not generated by AI.
- GoodLabs - product page (pricing context)(verified 2026-03-23)
- Quest - consumer lab shop (pricing context)(verified 2026-03-23)
- LabCorp OnDemand - Complete Blood Count (pricing context)(verified 2026-03-23)
- MedlinePlus - Complete Blood Count (CBC) overview
- MedlinePlus Medical Encyclopedia - Complete blood count (reference ranges)
- Clinical context: LabRecon editorial team. Not medical advice. For informational use only.
Complete cellular evaluation of peripheral blood. Screens for anemia, infection, inflammation, polycythemia, and platelet disorders.