Utilidad de la procalcitonina (PCT) en Unidades de Cuidados Intensivos.

Dr. Rafael Pitarch-UCI Hospital de Manacor-2008

PCT
Utilidad como marcador de enfermedad bacteriana

Niveles normales e interpretación resultados

Causas No bacterianas de incremento de PCT
Falsos negativos
Referencias

PCT: proteina de 116 aminoacidos de secuencia similar a la prohormona (32 aa.) de la calcitonina. La calcitonina es producida exclusivamente por las células C de la tiroides como respuesta a los estímulos hormonales, mientras que la PCT puede ser producida por células de diferentes tipos y por diversos órganos como respuesta a los estímulos pro-inflamatorios, particularmente por productos bacterianos.

La PCT No presenta la sensibilidad y especificidad suficiente para poder discriminar entre SIRS y Sépsis en pacientes críticos  (1) (2) Las conclusiones de este meta-analisis no prestan soporte suficiente para el uso rutinario de la PCT en unidades de cuidados críticos. Tampoco se  recomienda estandarizar su uso en la evaluación de fiebre postoperatoria, pancreatitis, EPOC, o pacientes neutropénicos con cancer.

Puede tener utilidad como indicador pronóstico, para apoyar el diagnostico de enfermedad bacteriana (siempre dentro de contexto clínico compatible) y monitorizar la respuesta al tto antibiótico.Volver al Indice

Niveles normales: < 0,05 ng/ml.

Interpretacion de resultados:

  • PCT <0.5 ng/ml : Sépsis poco probable
    • Niveles mas bajos no descartan infección
    • Puede tratarse de infecciones de < de 6 horas de evolución
    • Bajo riesgo de progresar a sepsis grave.
  • PCT >0.5 and <2 ng/ml: Sepsis posible.
    • Riesgo moderado de evolucionar a Sepsis grave.
    • Condiciones no bacterianas que pueden aumentar niveles de PCT
  • PCT >2 and <10 ng/ml: Sepsis es probable, a menos que otras causas sean conocidas.
    • Alto riesgo de progresión a sepsis grave
  • PCT >10 ng/ml: indica SIRS importante debida casi exclusivamente a sepsis grave o shock séptico
    • Alto riesgo de progresión a sepsis grave shock séptico.Volver al Indice

Situations described where PCT can be elevated by non-bacterial causes. These include, but are not limited to

  • neonates < 48 hours of life (physiological elevation)
  • the first days after a major trauma, major surgical intervention, severe burns, treatment with OKT3 antibodies and other drugs stimulating the release of pro-inflammatory cytokines
  • patients with invasive fungal infections, acute attacks of plasmodium falciparum malari
  • patients with prolonged or severe cardiogenic shock, prolonged severe organ perfusion anomalies, small cell lung cancer, medullary C-cell carcinoma of the thyroid.Volver al Indice

Low PCT levels not always indicate absence of bacterial infection.
Falsely low PCT levels in the presence of bacterial infection may accour eg. in case of

  • early course of infections
  • localised infections (see chapter PCT & Infection)
  • subacute infectious endocarditis.

Normal range in neonates
(including 95% of all measurements)

Age in hours
PCT [ng/ml]
Age in hours
PCT [ng/ml]
0-6
2
30-36
15
6-12
8
36-42
8
12-18
15
42-48
2
18-30
21
 

Bibliografía

1.-Lever, Andrew1; Mackenzie, Iain2. Sepsis: definition, epidemiology, and diagnosis[CLINICAL REVIEW] © 2007 BMJ Publishing Group Ltd Volume 335(7625), 27 October 2007, pp 879-883
  • The most robust systematic review available concerns the plasma procalcitonin concentration assay, which is not yet widely available, used to identify patients with sepsis among critically ill patients in hospital. 2 This study concludes that the test "cannot accurately distinguish sepsis from SIRS [systemic inflammatory response syndrome] in critically ill adult patients. "
2.- Tang BM, 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;7:210–7.
  • Procalcitonin is widely reported as a useful biochemical marker to differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome. In this systematic review, we estimated the diagnostic accuracy of procalcitonin in sepsis diagnosis in critically ill patients. 18 studies were included in the review. Overall, the diagnostic performance of procalcitonin was low, with mean values of both sensitivity and specificity being 71% (95% CI 67-76) and an area under the summary receiver operator characteristic curve of 0.78 (95% CI 0.73-0.83). Studies were grouped into phase 2 studies (n=14) and phase 3 studies (n=4) by use of Sackett and Haynes' classification. Phase 2 studies had a low pooled diagnostic odds ratio of 7.79 (95% CI 5.86-10.35). Phase 3 studies showed significant heterogeneity because of variability in sample size (meta-regression coefficient -0.592, p=0.017), with diagnostic performance upwardly biased in smaller studies, but moving towards a null effect in larger studies. Procalcitonin cannot reliably differentiate sepsis from other non-infectious causes of systemic inflammatory response syndrome in critically ill adult patients. The findings from this study do not lend support to the widespread use of the procalcitonin test in critical care settings.
3.- UptoDate©2007 www.uptodate.com
4.- B·R·A·H·M·S Diagnostica http://www.procalcitonin.com