HIT risk assessment
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Chest / 141 / 2 / February, 212 Supplement / e499S
"Treatment and Prevention of Heparin-Induced Thrombocytopenia"

Indication: $[indication for Hep/LMWH]$
Exposure >4d: $[>4d exposure: Yes/No]$
Substance: $[name of Hep/LWMH]$

HIT risk in postoperative patients:
   1-5% -- Heparin, any dose
 0.1-1% -- Heparin, flushes (case reports only)
 0.1-1% -- LMWH, any dose
   1-3% -- cardiac surgery (?Heparin)

HIT risk in non-surgical patients:
     1% -- cancer (?Heparin)
 0.1-1% -- Heparin, any dose
  <0.1% -- Heparin, flushes
   0.6% -- LMWH, any dose
   0.4% -- ICU (?Heparin)
  <0.1% -- Obstetrics (?Heparin)

(risk of HIT from Heparin generally 10x that of HIT from LMWH)

Risk estimate: $[risk estimate]$

If risk > 1% platelet monitoring every 2-3 days from
day 4 to day 14 or until exposure stops is suggested.

No monitoring is suggested if the risk is < 1%.

Monitor: $[Monitor ?  Yes/No]$

Diagnostic hints:
 typically at 5-10 days after begin of exposure platelets fall to
   < 150x10^9/l
     (occurs in 85-90% of patients developing HIT)
 or to
   30-50% of pre-exposure value even if > 150x10^9/l
     (occurs in 90-95% of patients developing HIT)
