Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1160 page)

   Pretransfusion testing may be complicated in recently transfused and marrow transplant patients.

PROCALCITONIN (PCT)

   Definition

   Procalcitonin (PCT) is a protein that can act as a hormone and a cytokine. It can be produced by several types of cells and many organs in response to proinflammatory stimuli, particularly bacterial infection. It is released under the stimulation of sepsis. PCT levels rise within 6 to 12 hours of bacterial infection with septic consequences.

   
Procalcitonin (PCT) measurement is indicated:

   On admission to the intensive care unit (ICU) in patients with a known or suspected respiratory infection, or sepsis with a probable bacterial source.

   In patients in the ICU with a suspicion of a new or relapsed respiratory infection or sepsis.

   On days 3 and 5 of a course of antimicrobial therapy being given to treat a respiratory infection, or potential sepsis for which a source has not been identified, to aid in assessing response to therapy and in clinical decisions of continuing versus discontinuing antimicrobial therapy.

   
Normal range:

   Negative: <0.10 ng/mL

   Use

   Diagnosis of bacteremia and septicemia in adults and children (including neonates)

   Diagnosis, risk stratification, and monitoring of septic shock

   Differential diagnosis of bacterial versus viral meningitis