The Utility of Serum C-Reactive Protein in Differentiating Bacterial from Nonbacterial Pneumonia in Children: A Meta-Analysis of 1230 Children.

Background: Differentiating bacterial from nonbacterial community-acquired pneumonia in children is difficult. Although several studies have evaluated serum concentrations of C-reactive protein (CRP) as a predictor of bacterial pneumonia in this patient population, the utility of this test remains unclear.

Objective: The purpose of this meta-analysis was to quantitatively define the utility of serum CRP as a predictor of bacterial pneumonia in acutely ill children.

Methods: Multiple databases were searched, bibliographies reviewed, and 2 authorities in the field were queried. Studies were included if: (1) the patient population was between 1 month and 18 years of age; (2) CRP was quantified in all subjects as part of the initial evaluation of a suspected, infectious, pulmonary process; (3) a cutoff serum CRP concentration between 30 and 60 mg/dL was used to distinguish nonbacterial from bacterial pneumonia; (4) some criteria were applied to differentiate bacterial from nonbacterial or viral pneumonia; (5) all patients were acutely ill; and (6) a chest radiograph was obtained as part of the initial evaluation. The quality of each included study was determined across 4 metrics: diagnostic criteria; study design; exclusion of chronically ill or human immunodeficiency virus infected subjects; and exclusion of patients who recently received antibiotics. Data was extracted from each article; the primary outcome measure was the odds ratio of patients with bacterial or mixed etiology pneumonia and serum CRP concentrations exceeding 30-60 mg/L. Heterogeneity among the studies was determined by Cochran's Q statistic; the methods of both Mantel and Haenszel, and DerSimonian and Laird were used to combine the study results.

Results: Eight studies fulfilled inclusion criteria. Combining all of the studies demonstrated a pooled study population of 1230 patients with the incidence of bacterial infection of 41%. Children with bacterial pneumonia were significantly more likely to have serum C-reactive protein (CRP) concentrations exceeding 35-60 mg/L than children with nonbacterial infections (odds ratio = 2.58, 95% confidence interval = 1.20-5.55). Sensitivity analysis demonstrated that this difference was robust. There was significant heterogeneity among the 8 studies (Q = 37.7, P < 0.001, I2 = 81.4) that remained throughout the sensitivity analysis.

Conclusions: In children with pneumonia, serum CRP concentrations exceeding 40-60 mg/L weakly predict a bacterial etiology.

(C) 2008 Lippincott Williams & Wilkins, Inc

ARTICLE

Usefulness of C-Reactive Protein and Left Ventricular Diastolic Performance for Prognosis in Patients With Left Ventricular Systolic Heart Failure

High-sensitivity C-reactive protein (hs-CRP) is a hepatocyte-derived inflammatory cytokine shown to be increased in the setting of acute heart failure (HF), particularly with increased intracardiac filling pressures. In the chronic HF setting, the relation between hs-CRP and echocardiographic indexes of left ventricular (LV) diastolic performance has not been examined. We measured plasma hs-CRP levels using a particle-enhanced immunonephelometry assay (Dade Behring, Inc., Deerfield, Illinois) in 136 subjects with chronic HF (LV ejection fraction [EF] ≤35%, New York Heart Association functional classes II to IV). We performed echocardiography, including color M-mode and tissue Doppler methods. We prospectively examined subjects’ death, cardiac transplantation, and HF hospitalization status over 33 ± 17 months. In our study cohort (mean LVEF 26 ± 6%, median plasma hs-CRP 3.19 mg/L), plasma hs-CRP levels progressively increased with worsening LV diastolic dysfunction. In particular, plasma hs-CRP levels correlated with mitral E/A wave ratio (Spearman r = 0.25, p = 0.004), mitral deceleration time (r = −0.28, p = 0.002), pulmonary vein systolic wave/diastolic wave ratio (r = −0.32, p <0.001), mitral E wave/color M-mode velocity of propagation ratio (r = 0.28, p = 0.001), and mitral E wave/tissue Doppler septal E′ wave ratio (r = 0.28, p = 0.001). Plasma hs-CRP levels independently predicted adverse clinical events even after adjustment for LVEF and mitral E wave/tissue Doppler septal E′ wave ratio (hazard ratio 2.28, 95% confidence interval 1.18 to 4.39). In conclusion, in patients with chronic systolic HF, expression of circulating CRP was associated with increasing echocardiographic indexes of diastolic dysfunction. High plasma hs-CRP levels portend poor long-term outcomes, particularly in those with severe concomitant systolic and diastolic dysfunctions.


W.H. Wilson Tang, MDa, Kevin Shrestha, ABa, Frederick Van Lente, PhDb, Richard W. Troughton, MBBSc, Maureen G. Martin, RDCSa, Allen G. Borowski, RDCSa, Sue Jasper, RN, BSNa, Allan L. Klein, MDa

InfectCheck CRP Barcode-Style Lateral Flow Assay for Semi-Quantitative Detection of C-reactive Protein in Distinguishing between Bacterial and Viral..

In the present study, we describe an InfectCheck barcode-style lateral flow assay for semi-quantitative detection of C-Reactive Protein in distinguishing between bacterial and viral infections. The severity of bacterial infection can be assessed by simply counting the number of red lines developed at the CRP test zone of the test device. If only one visible line appeared at the CRP test zone, it represents a low or mild inflammation with C-Reactive Protein levels < 10 mg/L. Two and three visible lines mean moderate (≥ 10–25 mg/L) and severe (≥ 25–50 mg/L) inflammations respectively while four visible lines stand for a very severe inflammation (≥ 50–100 mg/L). If the visible lines become faint and the intensity of the first line is weaker than that of the control line and may even disappear, this outcome corresponds to the stage of having super severe inflammation (≥ 100 mg/L). A total of 500 patients admitted to hospital through the Accident and Emergency Unit at the Prince of Wales Hospital were examined. The InfectCheck CRP barcode-style rapid test gave a high sensitivity of 88.7% and a high negative predictive value of 93.8%. This result indicates that the rapid test is reliable to exclude non-infected patients. The calculated intra- and inter-assay coefficient of variation for the five C-Reactive Protein concentration ranges was both within 20.0%. It is a one-step whole blood rapid test without any sample pre-treatment and the result is available within 20 min. This user friendly diagnostic tool can allow self-testing by interested individuals without any expensive reading device.

Leung W, Chan CP, Rainer TH, Ip M, Cautherley GW, Renneberg R.