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Three Part Question

'[Is procalcitonin more sensitive or specific] than other currently available biomarkers for [identifying serious bacterial infection] [in the undifferentiated patient presenting to the emergency department with SIRS criteria]?

Clinical Scenario

A 55 year old female presents to the ED with the complaint of fever, chills, weakness. Upon presentation she appears pale Vitals are Temp 39, HR 105, RR 22 and WBC count 13,000. Given this patient meets SIRS criteria, will a procalcitonin level accurately diagnose serious bacterial infection?

Search Strategy

Pub med 2002-2012
details of search [procalcitonin and sepsis and sirs][limited to english and human]

Search Outcome

returned 354 articles, 9 of which were reviewed, 4 of which were found to be relevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Joo Suk Oh MD Received 4 June 2008; revised Republic of Korea	80 patients (36 women, 44 men) mean age 65 who were admitted to the emergency department for suspected infection	Prospective Cohort Study	PCT levels	For PCT = 2 ng/ml, Sensitivity 93.94%, Specificity 87.23%, PPV 87.38%, NPV 95.35%, PLR 7.36, NLR 0.069, AUC 0.916 for detecting sepsis/septic shock	Small sample size, used initial variables for Apache II/SOFA scoring, unable to differentiate viral from bacterial causes
Benjamin M P Tang et al. 2007 Austrailia	18 studies included, 2097 patients, of which 1452 were ICU, 440 Emergency Dept, and 205 from hospital wards	Systematic review and meta-analysis	Sensitivity and specificity of PCT for diagnosing sepsis:	Sensitivity and Specificity 71% (95% CI 67-76), AUC 0.78 (95% CI 0.73-0.83).	Excluded studies that did not provide enough info to fit into 2x2 table, excluded studies that specifically focused on pediatrics, cardiac, burns, abdominal sepsis, meningitis, did not include risk stratification or prognosis studies
E.J. Giamarellos-Bourboulis et al. 2009 Greece	1156 Hospitalized patients, 234 ICU patients and 922 ward patients, PCT was sampled within 24 hr of onset of sepsis	Prospective multicenter observational investigation	Mortality	Among patients outside the ICU, mortality was 8% in those with PCT ≤0.12 ng/mL but 19.9% in those with PCT >0.12 ng/mL [P < 0.0001, odds ratio (OR) for death: 2.606; 95% confidence interval (CI): 1.553-4.371]. Among patients whose sepsis presented in ICU, mortality was 25.6% in those with PCT ≤0.85 ng/mL but 45.3% in those with PCT >0.85 ng/mL (P 0.002; OR for death: 2.404; 95% CI: 1.385-4.171).	Predominance of gram negative sepsis questions whether results would apply to other types of sepsis, patients diagnosed with sepsis on the floor were not transferred to the ICU
Reinhart K, 2011 Germany	75 articles included in review, 1186 patients including adults and children	systematic review and meta-analysis	Acute Meningitis Viral Vs Bacterial in Children , PCT cutoff 0.5 microg/dl	Sensitivity 94% Specificity 100%	Large review article, no major weaknesses
			Autoimmune Disorders: infectious vs non infectious, PCT cutoff 0.5 g/dl	Sensitivity 100% Specificity 84%
			Renal Transplantation acute rejection vs infection, PCT cutoff 0.5 microgram/dl	Sensitivity 87% Specificity 70%
			Pneumonia Bacterial Vs Viral, PCT cutoff 2 ng/dl	Sensitivity 63%, Specificity 96%
			Invasive Vs local infection in children, PCT cutoff 0.9 ng/dl	Sensitivity 93%, Specificity 78%
			Pancreatitis sterile vs infected necrosis, PCT cutoff 1.8 microg/L	Sensitivity 94%, Specificity 91%
			ICU patients, infection Vs no infection, PCT cutoff 0.6 microg/L	Sensitivity 67% Specificity 61%

Comment(s)

Procalcitonin is a promising bio-marker in detecting serious bacterial infection and sepsis, although not the gold standard. In the above studies there are wide ranges for sensitivity and specificity which lowers it’s usefulness as a single diagnostic marker. Although, Procalcitonin does outperform CRP repeatedly at detecting SBI. Procalcitonin has proven to be a excellent tool when used in conjunction with clinical judgment. Serum levels do seem to correlate with severity of disease, help differentiate bacterial vs viral infections, systemic vs local infections, and could help with the disposition of patient to the critical care setting when the clinical presentation is confusing or when the diagnosis is in doubt

Editor Comment

KdW

Clinical Bottom Line

Procalcitonin alone cannot reliably predict serious bacterial infection in the Emergency Department setting. But when used along with clinical judgement and other diagnostic tools Procalcitonin can help detect serious bacterial infection in patients presenting with SIRS.

References

1. Joo Suk Oh MD, Seong Uk Kim MD, Young Min Oh MD, Se Min Choe MD, Gyeong Ho Choe MD, Seung Pil Choe MD, Young Min Kim MD, Tae Yong Hong MD, Kyu Nam Park MD The usefulness of the semiquantitative procalcitonin test kit as a guideline for starting antibiotic administration
2. Benjamin M P Tang, Guy D Eslick, Jonathan C Craig, Anthony S McLean Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis
3. E.J. Giamarellos-Bourboulis a,*, I. Tsangaris b, Th. Kanni a, M. Mouktaroudi a, I. Pantelidou a, G. Adamis c, S. Atmatzidis d, M. Chrisofos e, V. Evangelopoulou f, F. Frantzeskaki b, P. Giannopoulos g Procalcitonin as an early indicator of outcome in sepsis: a prospective observational study
4. Konrad Reinhart, Dr Meda, Michael Meisner, Dr Med Habilb, Biomarkers in the Critically Ill Patient: Procalcitonin