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Laboratory tests

A regional or teaching hospital
If full laboratory facilities are available, use them! The following should be performed, labelled urgent:

  • Extended coagulation studies; prothrombin time/international normalised ratio (PT/INR), activated partial thromboplastin time (apt), fibrinogen level, cross linked or d-dimer degradation products of fibrin/ fibrinogen degradation products (XDP/FDP).
  • Complete blood picture; especially platelet and absolute lymphocyte counts.
  • Electrolytes, urea, creatinine.
  • Creatinine phosphokinase
  • Where appropriate, arterial blood gas estimation.
  • Examination of peripheral blood smear for evidence of microangiopathic hemolysis, suggestive of disseminated intravascular coagulation.
  • Only in Australia; snake venom detection on the bite site swab (see “Venom detection” in chapter on Australian snakebite).

In a large Australian city or country regional or base hospital, the following tests are required:

  • Venom detection using the SVDK.
  • Extended coagulation studies (PT/INR, aPTT, fibrinogen, FDP/XDP).
  • CBP/FBP/CBE (especially platelet count and absolute lymphocyte count).
  • Electrolytes and renal function.
  • CK

If initial tests are normal, repeat 2-3 hours and 5-6 hours later, or earlier if symptoms of envenoming develop. If initial tests are abnormal and antivenom therapy is commenced, re-test at 3 hours after completion of antivenom, to decide if more antivenom is needed (if there is a coagulopathy present).