PCT, or procalcitonin, is secreted in small amounts by parafollicular cells of the thyroid gland under normal physiologic conditions, with a normal reference range of 0-0.5ng/mL.
PCT has a high specificity for the diagnosis of bacterial infections. PCT greater than 0.5ng/mL is considered to be mildly elevated, suggesting that an infection may exist.
PCT greater than 2ng/mL is moderately elevated, suggesting the possible existence of serious infection or sepsis; PCT greater than 10ng/mL is significantly elevated, suggesting the possible existence of septic shock or serious trauma and major surgery.
However, there are some non-infectious factors such as Kawasaki disease, acute pancreatitis, subacute thyroiditis, graft-versus-host disease, etc., which can also lead to its elevation.
At present, PCT is of great clinical value in the early diagnosis of bacterial infections, determining the severity of the disease, and judging the efficacy of anti-infective therapy and prognosis, etc. If the phenomenon of elevated PCT occurs, it is recommended to consult a doctor in a timely manner, find out the cause of the disease, and treat the cause of the disease under the guidance of a physician.