Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
It's part of a complete blood count (CBC).
Clumped platelets in the tube can give a falsely low count; the test may be repeated in a different tube.
Why it's done
- Easy bruising, nosebleeds, or bleeding gums
- Tiny red or purple spots on the skin
- Monitoring medicines that affect platelets
Getting ready and what happens
- No special preparation is needed.
How the test is done
- A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.
What the results mean
| Result | Typical range for adults |
|---|---|
| Platelets | About 150,000 to 450,000 per microliter |
Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.
Low (thrombocytopenia)
Causes include viral infections, medicines (including heparin), immune conditions (ITP), liver disease, and heavy drinking. Bleeding risk rises a lot below about 20,000 to 30,000.
High (thrombocytosis)
Usually a reaction to infection, inflammation, iron deficiency, or surgery. Rarely, a marrow disorder.
When a result needs quick action
Call 911Bleeding that won't stop, blood in vomit or stool, or a severe headache with low platelets
Call your provider todayNew tiny red or purple spots, or much more bruising
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related tests
Sources
Last updated 2026-11-13.