Cyanosis differential diagnosis (mnemonic)

Last revised by Daniel J Bell on 23 May 2022

A mnemonic to differentiate between central and peripheral cyanoses is:



  • C: cold (peripheral)
  • O: obstruction (peripheral)
  • L: LVF and shock (peripheral)
  • D: decreased cardiac output (peripheral)
  • P: polycythemia (central)
  • A: altitude (central)
  • L: lung disease (central)
  • M: met-sulfhaemoglobinaemia (central) 
  • S: shunt (central)

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