SIRS criteria an immune response to infection can be diagnosed by ( 96.8<Temp>100.4, HR>90, RR>20 and 4K<WBC>12k). A new study in 172 ICUs among 109,663 patients with infection and
organ failure found that 87.9% had SIRS +Ve and 12.1% had SIRS -Ve severe sepsis. This method to define septic patient missed one in eight patients with similar findings in a high risk group. This is another reason that we should treat the patient, not the number!