Procalcitonin

Procalcitonin (PCT) is a precursor peptide of calcitonin.

Properties

Procalcitonin is a 116 amino acid peptide synthesized from the CALC-I gene located on chromosome 11. In recent years it has aroused great interest due to its role as a secondary mediator in systemic inflammatory response syndrome (SIRS)., especially for its usefulness for the diagnosis of sepsis.

Under normal conditions, it is synthesized in small amounts in the C cells of the thyroid gland and in neuroendocrine cells of the lung. However, in situations of sepsis it is synthesized in tissues and organs as disparate as the spleen, liver, testicles, fat or brain, so its blood levels skyrocket. Curiously, the large increase in the production of procalcitonin is not accompanied by a parallel increase in calcitonin levels, which hardly change.

Utility

There have been numerous studies in which procalcitonin has been shown to be a promising marker of infection. Helps distinguish sepsis from other causes of SIRS, detect invasive bacterial infection in children with fever without source, differentiate between infection and acute rejection in transplant patients, early diagnosis of sepsis in newborns, assess the presence of infection in patients undergoing surgery major etc A meta-analysis has shown a sensitivity of 76% and a specificity of 70%.

Below 1 ng/mL are considered normal levels of procalcitonin in the blood. Above this level we can say that they are elevated. Measurements greater than 10 ng/mL are almost exclusive of severe sepsis, septic shock, and multiple organ failure.

In association with the C-reactive protein test, sepsis levels are significantly diagnosed.