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.
Triggering receptor expressed on myeloid cells-1 (TREM1) may be a more accurate serum biomarker for diagnosing infection.[1][2]
Uses
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,[1] 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.[2] 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%.[3]
Diagnosis of bacteremia in the elderly has been studied.[4]
- Sensitivity 96%
- Specificity 68%
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".[5]. However, a nonrandomized, observational study reported "limited, prognostic value" of the procalcitonin[6].
Procalcitonin has been used in prediction of mortality in community-acquired pneumonia:[7]
- Sensitivity 35%
- Specificity 92%
References
- ^ Meisner M, Tschaikowsky K, Palmaers T, Schmidt J. Comparison of procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations at different SOFA scores during the course of sepsis and MODS. Crit Care. 1999;3(1):45-50. PMID 11056723 Full Text
- ^ Balci C, Sungurtekin H, Gurses E, Sungurtekin U, Kaptanoglu B. Usefulness of procalcitonin for diagnosis of sepsis in the intensive care unit. Crit Care. 2003 Feb;7(1):85-90. Epub 2002 Oct 30. PMID 12617745 Full Text
- ^ Tang Benjamin; Eslick GD; Craig JC; McLean AS. Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis.Lancet Infect Dis. 2007 7(3) 210-7 PMID 17317602
- ↑ Su L, Han B, Liu C, Liang L, Jiang Z, Deng J; et al. (2012). "Value of soluble TREM-1, procalcitonin, and C-reactive protein serum levels as biomarkers for detecting bacteremia among sepsis patients with new fever in intensive care units: a prospective cohort study". BMC Infect Dis. 12: 157. doi:10.1186/1471-2334-12-157. PMC 3426475. PMID 22809118.
- ↑ Gibot S, Kolopp-Sarda MN, Béné MC, Cravoisy A, Levy B, Faure GC; et al. (2004). "Plasma level of a triggering receptor expressed on myeloid cells-1: its diagnostic accuracy in patients with suspected sepsis". Ann Intern Med. 141 (1): 9–15. PMID 15238365.
- ↑ Jones AE, Fiechtl JF, Brown MD, Ballew JJ, Kline JA (2007). "Procalcitonin test in the diagnosis of bacteremia: a meta-analysis". Annals of emergency medicine. 50 (1): 34–41. doi:10.1016/j.annemergmed.2006.10.020. PMID 17161501.
- ↑ Lai CC, Chen SY, Wang CY, Wang JY, Su CP, Liao CH; et al. (2010). "Diagnostic value of procalcitonin for bacterial infection in elderly patients in the emergency department". J Am Geriatr Soc. 58 (3): 518–22. doi:10.1111/j.1532-5415.2010.02730.x. PMID 20163483.
- ↑ Christ-Crain M, Jaccard-Stolz D, Bingisser R, Gencay MM, Huber PR, Tamm M, Müller B (2004). "Effect of procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised, single-blinded intervention trial". Lancet. 363 (9409): 600–7. doi:10.1016/S0140-6736(04)15591-8. PMID 14987884.
- ↑ Brunkhorst FM, Al-Nawas B, Krummenauer F, Forycki ZF, Shah PM (2002). "Procalcitonin, C-reactive protein and APACHE II score for risk evaluation in patients with severe pneumonia". Clin. Microbiol. Infect. 8 (2): 93–100. PMID 11952722.
- ↑ Huang DT, Weissfeld LA, Kellum JA, Yealy DM, Kong L, Martino M; et al. (2008). "Risk prediction with procalcitonin and clinical rules in community-acquired pneumonia". Ann Emerg Med. 52 (1): 48–58.e2. doi:10.1016/j.annemergmed.2008.01.003. PMC 2775454. PMID 18342993.
External link
- Procalcitonin - web site of the manufacturer of the PCT assay.
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