Is serum procalcitonin a reliable diagnostic marker in children with acute respiratory tract infections? A retrospective analysis

Diagnostic Value of the Triple Combination of Serum Heparin-Binding Protein, Procalcitonin, and C-Reactive Protein in Children with Acute Bacterial Upper Respiratory Tract Infection

To investigate the role of the triple combination serum heparin-binding protein (HBP), procalcitonin (PCT), and C-reactive protein (CRP) in children with acute bacterial upper respiratory tract infection (ABURTI). A total of 130 children with upper respiratory tract infection admitted to the Department of Pediatrics of Fujian Maternity and Child Health Hospital from September 2019 to January 2021 were selected as the research group. According to the results of pathogenic analysis, children were further subdivided into a bacterial infection group (n = 67) and a viral infection group (n = 63). Additionally, 65 children who underwent physical examinations in our hospital during the same period were collected and included into the control group (n = 65). All patients selected were treated with cefixime granules orally for 5 days. Serum HBP level, serum PCT level, and serum CRP level were measured by double antibody Sandwich Enzyme Linked Immunosorbent Assay (ELISA), fluorescence method, and immunoturbidimetric assay, respectively. The expression levels of the three indicators in the serum of all subjects were compared, and the receiver operating characteristic (ROC) curve was used to analyze their diagnostic value in children with ABURTI. Furthermore, according to clinical efficacy of children with bacterial infections, they were divided into a good efficacy group (markedly effective) and a poor efficacy group (effective + ineffective) to compare serum HBP, PCT, and CRP levels between the two groups. The ROC curve was drawn to analyze the value of the three indicators in predicting the curative effect in children with ABURTI. Pearson test was used to analyze the correlation among the expression of HBP, PCT, and CRP. Results showed that the expression levels of HBP, PCT, and CRP in the serum of children in the bacterial infection group were significantly higher than those in the other two groups. The positive rates of HBP, PCT, and CRP in children in the bacterial infection group were also significantly higher than those of the other two groups. The area under the curve (AUC) of the combined diagnosis of HBP, PCT, and CRP was 0.973, which was significantly higher than that of the single detection by any of the three indicators, which were 0.849, 0.819, and 0.854, respectively. The expression levels of HBP, PCT, and CRP in the serum of children in the good efficacy group were significantly lower than those in the poor efficacy group, and the AUC of the triple combination for predicting treatment efficacy was 0.959. Pearson test showed that there was a positive correlation between the serum expression of HBP, PCT, and CRP in children. HBP, PCT, and CRP were highly correlated in children with ABURTI, and their combined detection was of high diagnostic value among ABURTI patients, indicating that the three were expected to become potential indicators for efficacy prediction.

Neglected Variables in the Interpretation of Serum Procalcitonin Levels in Patients With Septic Shock

The interpretation of serum procalcitonin (PCT) levels in septic patients is facilitated by reviewing the known stimuli that activate the PCT family of genes. Herein we describe 7 pathways that, alone or in combination, can increase serum PCT levels. As a marker of activation of innate immunity, high PCT levels affect clinical diagnosis, can be trended as a measure of "source" control, and can guide duration of antibacterial therapy in septic patients. Low PCT levels reflect little to no activation of an innate immune response, influence the differential diagnosis, and support the discontinuation of empiric antibiotic therapy. Understanding the pathways that result in elevated serum PCT levels is necessary for interpretation and subsequent clinical management.

Utilization of serum procalcitonin as a biomarker in the diagnosis and treatment of children with bacterial hospital-acquired pneumonia

Hospital-acquired pneumonia (HAP) is one of the common infections in hospitalized patients. Early and prompt diagnosis of HAP is important because it aids in the appropriate selection of antibiotics and decreases the mortality and morbidity of patients. The investigation on serum procalcitonin (PCT) levels in pediatric patients is limited. Herein we aimed to evaluate the role of PCT in the early diagnosis of children with bacterial HAP. The study enrolled 264 children (< 14 years old) who were radiographically detected by pulmonary condensation chest X-rays. The HAP patients were stratified by patterns of microbiological detection of pathogens. Baseline white blood cell (WBC) count, neutrophil proportion, PCT, and C-reactive protein (CRP) were measured on admission. The laboratory findings and microbiological findings were analyzed and compared among groups. The median PCT concentration of patients with typical bacterial pathogens (3.95 ± 3.75 ng/mL) was significantly higher than the one of the patients with other pathogen types (median lower than 1.20 ng/mL). Correlation analysis indicated a significant correlation between PCT concentrations and the main inflammation makers including WBC count, neutrophil proportion, and CRP. PCT level was significantly decreased to 0.86 ± 1.46 ng/mL in post-treatment patients (p < 0.001). This cohort study with 264 pediatric HAP patients demonstrated the reliability of PCT level as a biomarker in patients with typical bacterial pathogens. Specifically, PCT cutoffs of 2 ng/mL accurately identified HAP children with typical bacterial pathogens. This finding suggested that PCT may serve as a reliable biomarker for the early diagnosis and treatment indicator of children with HAP.

Diagnostic accuracy of procalcitonin for bacterial pneumonia in children - a systematic review and meta-analysis

Objective: The predictive role of procalcitonin for childhood bacterial pneumonia, a leading cause of death, is unclear. We aimed to evaluate the diagnostic accuracy of procalcitonin for childhood bacterial pneumonia.Methods: Major bibliographic databases were searched from inception through September 2019 using pre-defined index terms, including 'procalcitonin,' 'pneumonia' and 'children'. The study is reported according to Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies. Meta-analyses of the diagnostic accuracy and odds ratio of procalcitonin for bacterial pneumonia were conducted along with subgroup analyses for different cut-offs of procalcitonin. The Quality Assessment of Diagnostic Accuracy Studies 2 instrument was used to assess the methodologic quality of eligible studies.Results: Twenty-five studies (with 2,864 patients) showed that procalcitonin for bacterial pneumonia had an overall sensitivity of 0.64 (95% confidence interval: 0.53-0.74), specificity of 0.72 (95% confidence interval: 0.64-0.79), positive likelihood ratio of 2.3 (95% confidence interval: 1.8-3.0) and negative likelihood ratio of 0.50 (95% confidence interval: 0.38-0.66), and Area Under the Receiver Operating Characteristics of 0.74 (95% confidence interval: 0.70-0.78). Using a cut-off of 0.5 ng/ml, Procalcitonin had a sensitivity of 0.68 (95% confidence interval: 0.50-0.82), specificity of 0.60 (95% confidence interval: 0.47-0.72), and Area Under the Receiver Operating Characteristics of 0.68 (95% confidence interval: 0.64-0.72). Using a cut-off of 2 ng/ml, procalcitonin had a sensitivity of 0.59 (95% confidence interval: 0.40-0.76), specificity of 0.71 (95% confidence interval: 0.58-0.81), and AUROC curve of 0.71 (95% confidence interval: 0.67-0.75). Elevated procalcitonin was not associated with increased odds of bacterial pneumonia (odds ratio: 1.36, 95% confidence interval: 0.81-1.92, p = .18). Quality assessment found minimal concerns for bias or applicability.Conclusions: Given the moderate diagnostic accuracy of procalcitonin for bacterial pneumonia, we recommend that procalcitonin be used in conjunction with other findings for management and disposition of children with pneumonia.

Role of Procalcitonin in the Management of Infected Patients in the Intensive Care Unit

The combination of molecular pathogen diagnostics and the biomarker procalcitonin (PCT) are changing the use of antimicrobials in patients admitted to critical care units with severe community-acquired pneumonia, possible septic shock, or other clinical syndromes. An elevated serum PCT level is good supportive evidence of a bacterial pneumonia, whereas a low serum PCT level virtually eliminates an etiologic role for bacteria even if the culture for a potential bacterial pathogen is positive. Serum PCT levels can be increased in any shocklike state; a low PCT level eliminates invasive bacterial infection as an etiology in more than 90% of patients.

Biomarkers for community-acquired pneumonia in the emergency department

Community-acquired pneumonia is one of the most common reasons for emergency department (ED) visits in children and adults. Despite its prevalence, there are many challenges to proper diagnosis and management of pneumonia. There is no accurate and timely etiologic gold standard to differentiate bacterial from viral disease, and there are limitations with precise risk stratification of patients to ensure appropriate site-of-care decisions. Clinical factors obtained by history and physical examination have limited the ability to diagnose pneumonia etiology and severity. Biomarkers offer information about the host response to infection and pathogen activity within the host that can serve to augment clinical features in decision-making. As science and technology progress, novel biomarkers offer great potential in aiding critical decisions for patients with pneumonia. This review summarizes existing knowledge about biomarkers of host response and pathogen activity, in addition to briefly reviewing emerging biomarkers using novel technologies.

Sensitivity and specificity of procalcitonin in predicting bacterial infections in patients with renal impairment

The objective of this study was to determine the sensitivity, specificity, positive and negative predictive values of procalcitonin levels for predicting bacterial infection in adult patients with renal impairment.

Background

 It is unclear whether procalcitonin is an accurate predictor of bacterial infections in patients with renal impairment, although it is used as a biomarker for early diagnosis of sepsis. We determined the sensitivity, specificity, positive and negative predictive values, accuracy and best predictive value of procalcitonin for predicting bacterial infection in adult patients with severe renal impairment.

Methods

 Retrospective study at a single-center community teaching hospital involving 473 patients, ages 18–65, with Modification of Diet in Renal Disease eGFR ≤30 ml/min per 1.73 m², admitted between January 2009 and June 2012, with 660 independent hospital visits. A positive or negative culture (blood or identifiable focus of infection) was paired to the highest procalcitonin result performed 48 hours before or after collecting the culture.

Results

 The sensitivity and specificity to predict bacterial infection, using a procalcitonin level threshold of 0.5 ng/mL, was 0.80 and 0.35 respectively. When isolating for presence of bacteremia, the sensitivity and specificity were 0.89 and 0.35 respectively. An equation adjusting for optimum thresholds of procalcitonin levels for predicting bacterial infection at different levels of eGFR had a sensitivity and specificity of 0.55 and 0.80 respectively.

Conclusions

 Procalcitonin is not a reliably sensitive or specific predictor of bacterial infection in patients with renal impairment when using a single threshold. Perhaps two thresholds should be employed, where below the lower threshold (i.e. 0.5 ng/mL) bacterial infection is unlikely with a sensitivity of 0.80, and above the higher threshold (i.e. 3.2 ng/mL) bacterial infection is very likely with a specificity of 0.75.

Procalcitonin in pediatrics

Over the past two decades, the body of literature on the clinical usefulness of procalcitonin (PCT) in adults has grown rapidly. Although this approach has led to increased insight, it has also prompted debate regarding its potential use in diagnosis and management of severe infection. Clinicians, however, are less familiar with the use of PCT in pediatric populations. In this review, we examine PCT as a marker of severe clinical pediatric conditions including its role in systemic inflammation, infection, and sepsis.

[Procalcitonin-based algorithm. Management of antibiotic therapy in critically ill patients]

Sepsis is one of the most cost-intensive conditions of critically ill patients in intensive care medicine. Furthermore, sepsis is known to be the leading cause of morbidity and of mortality in intensive care patients. Early initiation of antibiotic therapy can significantly reduce mortality. The development of resistance of bacterial species against antibiotics is a compelling issue to reconsider indications and administration of antibiotic treatment. Adequate indications and duration of therapy are particularly important for the use of highly potent substances in the intensive care setting. Until recently no laboratory marker has been available to distinguish bacterial infections from viral or non-infectious inflammatory responses. However, procalcitonin (PCT) appears to be the first among a large array of inflammatory markers that offers this possibility. Regular procalcitonin measurements can significantly shorten the length of antibiotic therapy, show positive influence on antibiotic costs and have no adverse affects on patient outcome.

Procalcitonin as a biomarker in respiratory tract infection

Serum procalcitonin (PCT) levels rapidly increase in patients with invasive bacterial disease. PCT levels increase faster than do C-reactive protein levels. Furthermore, a rapid decrease in the PCT level is supporting evidence that the source of the bacterial infection is responding to clinical management. In patients with community-acquired bacterial pneumonia, sequential PCT levels are useful as a guide to shorter courses of antimicrobial therapy. With use of emerging multiplex real-time polymerase chain reaction platforms for the detection of viral and bacterial respiratory pathogens, it should be possible to critically assess whether an elevated serum PCT level is a valid biomarker of invasive bacterial infection.

Use of plasma procalcitonin levels as an adjunct to clinical microbiology

Procalcitonin (PCT) is synthesized by a large number of tissues and organs in response to invasion by pathogenic bacteria, fungi, and some parasites. Current PCT assays are rapid, specific, and of sufficient sensitivity to detect increases in PCT serum levels within 4 to 6 h of initiation of infection. Clinically, PCT levels may help in decisions regarding the need for empirical antibiotic therapy, "source control" of infection, and duration of antibiotic therapy. The addition of PCT levels to bacterial culture and viral detection results can assist with the separation of colonization and invasion by pathogenic bacteria.

Procalcitonin in sepsis and systemic inflammation: a harmful biomarker and a therapeutic target

The worldwide yearly mortality from sepsis is substantial, greater than that of cancer of the lung and breast combined. Moreover, its incidence is increasing, and its response to therapy has not appreciably improved. In this condition, the secretion of procalcitonin (ProCT), the prohormone of calcitonin, is augmented greatly, attaining levels up to thousands of fold of normal. This hypersecretion emanates from multiple tissues throughout the body that are not traditionally viewed as being endocrine. The serum values of ProCT correlate with the severity of sepsis; they recede with its improvement and worsen with exacerbation. Accordingly, as highlighted in this review, serum ProCT has become useful as a biomarker to assist in the diagnosis of sepsis, as well as related infectious or inflammatory conditions. It is also a useful monitor of the clinical course and prognosis, and sensitive and specific assays have been developed for its measurement. Moreover, it has been demonstrated that the administration of ProCT to septic animals greatly increases mortality, and several toxic effects of ProCT have been elucidated by in vitro experimental studies. Antibodies have been developed that neutralize the harmful effects of ProCT, and their use markedly decreases the symptomatology and mortality of animals that harbour a highly virulent sepsis analogous to that occurring in humans. This therapy is facilitated by the long duration of serum ProCT elevation, which allows for a broad window of therapeutic opportunity. An experimental groundwork has been established that suggests a potential applicability of such therapy in septic humans.