Procalcitonin (PCT) has a set half-life of 20 to 24 hours which provides clinicians and researchers with a rough timeline of when levels should begin to decrease following physiological control of the systemic infection. When physiologic control is reached, PCT should decrease by approximately 50% over 24 hours. [10] Understand what a PCT ( procalcitonin ) blood test is for, its normal range, and what high or low results might mean. Learn how it helps diagnose infections and guide treatment. The Procalcitonin test, known as PCT, is used to measure the level of procalcitonin in the blood. It is an important indicator in cases of bacterial infection and the development of sepsis. In these two situations, where the body’s defense cells are intensely activated, procalcitonin levels typically peak between the second and fourth hours. In current clinical practice, procalcitonin (PCT) has developed into a promising new biomarker for the early detection of systemic bacterial infections. PCT is a 116-amino acid residue first explained by Le Moullec et al. in 1984; its diagnostic significance was not recognized until 1993.[1] In 1993, Assicot et al. demonstrated a positive correlation between high serum levels of PCT and patients with positive findings for bacterial infection and sepsis (e.g., positive blood cultures ...
