[1]
High trust
MedlinePlus: Complete blood count
Explains that a CBC usually needs no special preparation, unless other tests in the same blood sample require fasting.
Do you need to fast for a CBC blood test?
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Usually, a CBC by itself does not need fasting. But if the same blood draw includes other tests, the lab or clinician may ask you not to eat or drink anything except water for several hours. AI can explain the instructions, but the safest step is to follow the order, lab message, or clinician guidance for that exact blood draw.
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[2]
High trust
Mayo Clinic: Complete blood count
Patient-facing preparation guidance for eating, drinking, and fasting when other blood tests are ordered.
[3]
High trust
MedlinePlus: Fasting for a blood test
General patient guidance on fasting instructions and what to drink when fasting is required.
Not medical advice.
Use this page for source review, not diagnosis, treatment, medication changes, or emergency triage.