Platelets (PLT)
Platelets (PLT) are blood components also known as thrombocytes. They play a key role in blood clotting, stopping bleeding, and repairing blood vessel walls. Platelets are produced in the bone marrow from megakaryocytes and circulate in the blood for about 7–10 days.
Normal platelet values:
- 150–400 × 10⁹/L in adults
- Normal ranges may slightly differ in children
Functions of platelets:
- Formation of blood clots at sites of vascular injury
- Participation in tissue regeneration and wound healing
- Secretion of growth factors and inflammatory mediators
Increased platelets (thrombocytosis) may be observed in:
- Inflammatory diseases (rheumatoid arthritis, tuberculosis)
- Acute infections
- Iron deficiency anemia
- After surgical operations or blood loss
- Certain malignant tumors (especially myeloproliferative)
- After spleen removal (splenectomy)
Decreased platelets (thrombocytopenia) occurs in:
- Viral infections (flu, mononucleosis, HIV, etc.)
- Autoimmune diseases (systemic lupus erythematosus, ITP)
- Use of certain medications (heparin, cytostatics, antibiotics)
- Alcohol intoxication, vitamin B12 and folate deficiency
- Blood cancers (leukemias, myelodysplastic syndrome)
Risks of deviations:
- Low platelet levels increase the risk of bleeding, including internal and spontaneous (nosebleeds, gum bleeding, petechiae on skin)
- High platelet levels increase the risk of thrombosis, stroke, heart attack, and thromboembolism
Additional platelet parameters:
- MPV (mean platelet volume) — indicates platelet maturity and activity
- PDW — platelet size distribution width
- PCT (plateletcrit) — proportion of blood volume occupied by platelets
How to take the test:
- Blood is drawn fasting, usually in the morning
- Avoid alcohol and heavy physical activity 24 hours before the test
Important:
- PLT deviations require evaluation in the context of other parameters and clinical picture
- Accurate diagnosis may require repeat testing or additional investigations