Patients in the ICU whose infection is resolving will be randomized to standard duration of antibiotics compared to duration determined by a combination of a procalcitonin value and a simple evaluation of clinical status.

Inclusion Criteria:

• Adult patients (19 years and older) treated with ABx for reasons other than prophylaxis within the last 24 hours and who are admitted to a critical care environment.

Exclusion Criteria:

• Declined consent

• Any infection that according to evidence-based guidelines which would usually receive more than 2 weeks of antibiotic therapy including, but not limited to;

  • Infective endocarditis
  • Osteomyelitis
  • Undrained abscess

• Not expected to survive 48 hours

• Immunosuppression (HIV positive, any immunosuppressive medications, any steroid dose, neutrophil count less than 1.0)

• Previously enrolled in this study

• Presently enrolled in a separate study which is felt by study investigators to have biological or clinical process in conflict with this study.