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Pre-analytic factors and initial biomarker levels in community-acquired pneumonia patients

  • Kutz, Alexander1
  • Grolimund, Eva1
  • Christ-Crain, Mirjam2
  • Thomann, Robert3
  • Falconnier, Claudine4
  • Hoess, Claus5
  • Henzen, Christoph6
  • Zimmerli, Werner4
  • Mueller, Beat1
  • Schuetz, Philipp1
  • 1 University Department of Medicine, Kantonsspital Aarau, Tellstrasse, CH-5001, Switzerland , Tellstrasse (Switzerland)
  • 2 University Hospital Basel, Department of Internal Medicine, Division of Endocrinology, Diabetes and Clinical Nutrition, Basel, Switzerland , Basel (Switzerland)
  • 3 Bürgerspital Solothurn, Department of Internal Medicine, Solothurn, Switzerland , Solothurn (Switzerland)
  • 4 Basel University Medical Clinic Liestal, Liestal, Switzerland , Liestal (Switzerland)
  • 5 Kantonsspital Münsterlingen, Department of Internal Medicine, Münsterlingen, Switzerland , Münsterlingen (Switzerland)
  • 6 Kantonsspital Lucerne, Department of Internal Medicine, Lucerne, Switzerland , Lucerne (Switzerland)
Published Article
BMC Anesthesiology
Springer (Biomed Central Ltd.)
Publication Date
Nov 15, 2014
DOI: 10.1186/1471-2253-14-102
Springer Nature


BackgroundBlood biomarkers are increasingly used to diagnose, guide therapy in, and risk-stratify community-acquired pneumonia (CAP) patients in emergency departments (EDs). How pre-analytic factors affect these markers’ initial levels in this population is unknown.MethodsIn this secondary analysis of consecutive ED patients with CAP from a large multicentre antibiotic stewardship trial, we used adjusted multivariate regression models to determine the magnitude and statistical significance of differences in mean baseline concentrations of five biomarkers (procalcitonin [PCT], C-reactive protein [CRP], white blood cells count [WBC], proadrenomedullin [ProADM], copeptin) associated with six pre-analytic factors (antibiotic or corticosteroid pretreatment, age, gender, chronic renal failure or chronic liver insufficiency).ResultsOf 925 CAP patients (median age 73 years, 58.8% male), 25.5% had antibiotic pretreatment, 2.4%, corticosteroid pretreatment, 22.3%, chronic renal failure, 2.4% chronic liver insufficiency. Differences associated with pre-analytic factors averaged 6.1% ±4.6%; the three largest statistically significant changes (95% confidence interval) were: PCT, +14.2% (+2.1% to +26.4%, p = 0.02) with liver insufficiency; ProADM, +13.2% (+10.2% to +16.1%, p < 0.01) with age above median; CRP, -12.8% (-25.4% to -0.2%, p = 0.05) with steroid pretreatment. In post hoc sensitivity analyses, reclassification statistics showed that these factors did not result in significant changes of biomarker levels across clinically used cut-off ranges.ConclusionsDespite statistically significant associations of some pre-analytic factors and biomarker levels, a clinically relevant influence seems unlikely. Our observations reinforce the concept of using biomarkers in algorithms with widely-separated cut-offs and overruling criteria considering the entire clinical picture.Trial registrationIdentifier ISRCTN95122877.

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