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Complete Blood Count (CBC)

Platelet Count

Normal range 150–400 10³/µL (150–400 10⁹/L SI). Specimen: Whole blood (EDTA).

Also known as: thrombocyte count, PLT.

150–400 10³/µLCritical: read below

Reference range

Conventional10³/µL
150400
SI10⁹/L
150400
SpecimenWhole blood (EDTA)
Conventional range150–400 10³/µL
SI range150–400 10⁹/L
Conversion factor×1 (conventional → SI)
Critical value< 50 × 10⁹/L (bleeding risk) — spontaneous bleeding risk rises sharply < 20; > 1,000
PanelComplete Blood Count (CBC)

Convert any Platelet Count result between units on the unit converter.

What is the normal range for Platelet Count?

The standard teaching reference range for Platelet Count is 150–400 10³/µL in conventional units, or 150–400 10⁹/L in SI units. This value is measured in whole blood (edta).

A commonly taught critical (panic) value is < 50 × 10⁹/L (bleeding risk) — spontaneous bleeding risk rises sharply < 20; > 1,000. Critical results are reported to the provider immediately under your facility's policy.

Source: Adult reference values compiled from Pagana & Pagana, Mosby's Diagnostic and Laboratory Test Reference, and Fischbach & Dunning, A Manual of Laboratory and Diagnostic Tests. Reference ranges vary by laboratory, method, age, sex, and population — always use the range printed on the actual result.

Above the range

Common causes of a high Platelet Count

  • Reactive thrombocytosis (infection, inflammation, iron deficiency)
  • Splenectomy
  • Essential thrombocythemia
  • Malignancy

Below the range

Common causes of a low Platelet Count

  • Immune thrombocytopenia (ITP)
  • DIC
  • Heparin-induced thrombocytopenia (HIT)
  • Bone marrow suppression
  • Hypersplenism

At the bedside

Nursing considerations

  • Institute bleeding precautions when counts fall (typically < 50 × 10⁹/L).
  • Hold anticoagulants and avoid IM injections with severe thrombocytopenia per orders.
  • Suspect HIT when platelets fall ~50% several days after heparin exposure.

Study aid

Your notes on Platelet Count

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