Blood and lab tests
What Are Platelets on a Blood Test?
Platelets · say it: PLAYT-letsAlso written: PLT, platelet count, thrombocytes
Short answer
Platelets are tiny cell fragments in the blood that help it clot and stop bleeding; the count shows how many are in your sample.
What it means
When a blood vessel is damaged, platelets rush to the spot, stick together and form a plug. They also help start the chemical steps that make a firm clot.
A low platelet count (thrombocytopenia) can make bruising or bleeding more likely if it is low enough, and has many possible causes, including infections, medicines and immune conditions. A high count (thrombocytosis) is often a reaction to inflammation, infection or low iron.
Sometimes platelets clump together in the test tube, which makes the machine count fewer than are really there. Labs often re-check unexpected low counts for this reason.
Where you may see it
- Complete blood count (CBC)
- Pre-surgery and pre-procedure checks
- Monitoring during some medicines and treatments
📄 How it looks on a report
Platelets 135 x10^9/L L
🙅 What it does not mean
- A mildly low count does not usually mean you will bleed easily.
- A low result is not always real; clumping in the tube can cause a falsely low count.
- A high count does not automatically mean a blood disorder; it is often a reaction to something else.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “Platelets”
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💊 Medicines whose labels mention “Platelets”
Plain-English explanations of each medicine, from its official FDA label.
- Clopidogrel
A platelet inhibitor of the P2Y12 type (a thienopyridine). It is a blood thinner that keeps platelets from sticking together.
- Divalproex Sodium
An anti-epileptic (anti-seizure) drug of the valproate type. The label also uses it to treat manic episodes of bipolar disorder and to prevent migraine headaches.
- Methotrexate
A dihydrofolate reductase inhibitor, a type of medicine that works against folate (a vitamin-like substance cells use to grow and divide). The FDA pharmacologic class is not listed on the label.
- Pregabalin
an antiepileptic drug, which is a seizure medicine that is also used to treat certain types of nerve pain and fibromyalgia
- Spironolactone
An aldosterone antagonist, a type of prescription medicine the FDA classifies this way
- Sulfamethoxazole and Trimethoprim
An antibacterial combination of two medicines: a sulfonamide antimicrobial and a dihydrofolate reductase inhibitor antibacterial.
🔗 Read more from trusted sources
- “Platelets” on MedlinePlus ↗
US National Library of Medicine
- MedlinePlus lab test guides ↗
US National Library of Medicine
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