Platelets (PLT)
CBCNormal range
150,000–400,000 /mm³
SI: 150–400 ×10⁹/L
Critical low: < 50,000 /mm³ · Critical high: > 1,000,000 /mm³
☎ When to call
< 20,000 (spontaneous bleeding risk), any active bleeding below 50,000, or suspected HIT — call now. HIT means stopping ALL heparin including flushes.
What you do
- < 50K: bleeding precautions — soft toothbrush, no IM injections, pressure 5+ min after sticks
- On heparin with a 50% drop from baseline? Think HIT — flag it before the next dose
- Check for petechiae, gum bleeding, blood in urine/stool
Causes of HIGH platelets
Causes of LOW platelets
Source: Pagana, Mosby's Manual of Diagnostic and Laboratory Tests, 7th ed.Reference only — verify against your facility's policy.
