Procalcitonin

Procalcitonin (PCT) is a precursor of the hormone calcitonin, which is involved with calcium homeostasis, and is produced by the C-cells of the thyroid gland. It is there that procalcitonin is cleaved into calcitonin, katacalcin and a protein residue. It is not released into the blood stream of healthy individuals. With the derangements that a severe infection with an associated systemic response brings, the blood levels of procalcitonin may rise to 100 ng/ml. In blood serum, procalcitonin has a half-life of 25 to 30 hours.

Diagnosis and prognosis of sepsis
Measurement of procalcitonin can be used as a marker of severe sepsis and generally grades well with the degree of sepsis, although levels of procalcitonin in the blood are very low. PCT has the greatest sensitivity (85%) and specificity (91%) for differentiating patients with SIRS from those with sepsis, when compared with IL-2, IL-6, IL-8, CRP and TNF-alpha. However, the test is not routinely used and has yet to gain widespread acceptance.

Diagnosis of bacteremia
A meta-analysis reported a sensitivity of 76% and specificity of 70%.

Prognosis of pneumonia
A cluster randomized trial found that the procalcitonin level can help guide antibiotic therapy. In this trial, "on the basis of serum procalcitonin concentrations, use of antibiotics was more or less discouraged (<0.1 microg/L or <0.25 microg/L) or encouraged (> or =0.5 microg/L or > or =0.25 microg/L), respectively". . However, a nonrandomized, observational study reported "limited, prognostic value" of the procalcitonin.

External link

 * Procalcitonin - web site of the manufacturer of the PCT assay.

Procalcitonin Procalcitonina Procalcitonine