Prognostic utility of the semi-quantitative procalcitonin test, neutrophil count and C-reactive protein in meningococcal infection in children

AACC Guidance Document on the Clinical Use of Procalcitonin

BACKGROUND

Procalcitonin (PCT), a peptide precursor of the hormone calcitonin, is a biomarker whose serum concentrations are elevated in response to systemic inflammation caused by bacterial infection and sepsis. Clinical adoption of PCT in the United States has only recently gained traction with an increasing number of Food and Drug Administration-approved assays and expanded indications for use. There is interest in the use of PCT as an outcomes predictor as well as an antibiotic stewardship tool. However, PCT has limitations in specificity, and conclusions surrounding its utility have been mixed. Further, there is a lack of consensus regarding appropriate timing of measurements and interpretation of results. There is also a lack of method harmonization for PCT assays, and questions remain regarding whether the same clinical decision points may be used across different methods.

CONTENT

This guidance document aims to address key questions related to the use of PCT to manage adult, pediatric, and neonatal patients with suspected sepsis and/or bacterial infections, particularly respiratory infections. The document explores the evidence for PCT utility for antimicrobial therapy decisions and outcomes prediction. Additionally, the document discusses analytical and preanalytical considerations for PCT analysis and confounding factors that may affect the interpretation of PCT results.

SUMMARY

While PCT has been studied widely in various clinical settings, there is considerable variability in study designs and study populations. Evidence to support the use of PCT to guide antibiotic cessation is compelling in the critically ill and in some lower respiratory tract infections but is lacking in other clinical scenarios, and evidence is also limited in the pediatric and neonatal populations. Interpretation of PCT results requires guidance from multidisciplinary care teams of clinicians, pharmacists, and clinical laboratorians.

Clinical Predictors and Biomarkers in Children With Sepsis and Bacterial Meningitis

OBJECTIVES

Sepsis and meningitis in children may present with different clinical features and a wide range of values of inflammatory markers. The aim of this study was to identify the prognostic value of clinical features and biomarkers in children with sepsis and bacterial meningitis in the emergency department (ED).

METHODS

We carried out a single-center, retrospective, observational study on 194 children aged 0 to 14 years with sepsis and bacterial meningitis admitted to the pediatric ED of a tertiary children's hospital through 12 years.

RESULTS

Among epidemiological and early clinical features, age older than 12 months, capillary refill time greater than 3 seconds, and oxygen blood saturation lower than 90% were significantly associated with unfavorable outcomes, along with neurological signs ( P < 0.05). Among laboratory tests, only procalcitonin was an accurate and early prognostic biomarker for sepsis and bacterial meningitis in the ED, both on admission and after 24 hours. Procalcitonin cut-off value on admission for short-term complications was 19.6 ng/mL, whereas the cut-off values for long-term sequelae were 19.6 ng/mL on admission and 41.9 ng/mL after 24 hours, respectively. The cut-off values for mortality were 18.9 ng/mL on admission and 62.4 ng/mL at 24 hours.

CONCLUSIONS

Procalcitonin, along with clinical evaluation, can guide the identification of children at higher risk of morbidity and mortality, allowing the most appropriate monitoring and treatment.

Procalcitonin and Pediatric Traumatic Brain Injury: Differentiating Neuro-Storming From Infection

INTRODUCTION

Recurrent febrile episodes represent a diagnostic challenge in the pediatric traumatic brain injury (TBI) population as they may indicate presence of infection versus sterile neuro-storming. Procalcitonin (PCT) is a promising biomarker used in pediatric sepsis; however, data are limited regarding use in TBI. We hypothesized PCT helps discern neuro-storming from sepsis in children with TBI.

MATERIALS AND METHODS

A single-institution retrospective review (2014-2021) identified pediatric patients (aged 0-18 y) with moderate-to-severe TBI and intensive care unit admission > 2 d. Patients with multiple febrile events who underwent infectious evaluation including cultures and PCT drawn within 48 h of fever were included. Demographics, vital signs, infectious biomarkers including PCT, and culture data were captured. Univariate and multivariate analyses were performed to determine variables associated with culture positive status.

RESULTS

One hundred and fifty six patients were admitted to the intensive care unit with moderate-to-severe TBI during the study period. Eighty five patients (54%) experienced recurrent febrile episodes. Twenty four (28%) met inclusion criteria, undergoing 32 total infectious workups. Twenty one workups were culture-positive (66%) in a total of 18 patients. Median PCT levels were not statistically different between culture-positive and culture-negative workups (P = 0.94). In multivariate modeling, neither PCT [odds ratio 0.89 (confidence interval: 0.75-1.05)] nor temperature [odds ratio 7.34 (confidence interval: 0.95-57.16)] correlated with positive bacterial cultures.

CONCLUSIONS

In this small pilot analysis, recurrent febrile episodes were common and PCT did not correlate with sepsis or neuro-storming in pediatric TBI patients. Prospective protocols are needed to better understand the utility of PCT and identify predictors of bacterial infection to improve early diagnosis of sepsis in this population.

Utility of Procalcitonin as a Biomarker for Sepsis in Children

Sepsis is a complex process defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. It is associated with significant morbidity and mortality rates in both adults and children, and emphasis has been placed on its early recognition and prompt provision of antimicrobials. Owing to limitations of current diagnostic tests (i.e., poor sensitivity and delayed results), significant research has been conducted to identify sepsis biomarkers. Ideally, a biomarker could reliably and rapidly distinguish bacterial infection from other, noninfectious causes of systemic inflammatory illness. In doing so, a sepsis biomarker could be used for earlier identification of sepsis, risk stratification/prognostication, and/or guidance of antibiotic decision-making. In this minireview, we review one of the most common clinically used sepsis biomarkers, procalcitonin, and its roles in sepsis management in these three areas. We highlight key findings in the adult literature but focus the bulk of this review on pediatric sepsis. The challenges and limitations of procalcitonin measurement in sepsis are also discussed.

Neutrophilia is associated with a poorer clinical outcome in dogs with chronic hepatitis

BACKGROUND

Liver disease is a common cause of morbidity and mortality in dogs. Currently, it is challenging to prognosticate in these cases. The aim of this study was to evaluate the utility of the haematological variables in dogs with chronic hepatitis.

METHODS

Dogs with chronic hepatitis confirmed on histopathology had presenting haematological values retrospectively obtained and evaluated against survival time. Eighty-two dogs met the inclusion criteria and their data analysed.

RESULTS

Neutrophilic patients, with a count greater than 12×10⁹/l, controlled for sex and age, had a shorter survival time (P≤0.01). In dogs, neutrophilia at presentation predicted a poor outcome, whereas the other haematological parameters were not prognostically informative. When the dogs were split into even quarters on the basis of their neutrophil count, those within the higher quartiles had poorer survival times. Neutrophilia was associated with a poorer survival time in comparison to those patients with a lower count.

CONCLUSION

The relationship between neutrophils, inflammation and clinical outcome is deserving of future study in dogs with chronic hepatitis.

Relationship of Serum Procalcitonin, C-reactive Protein, and Lactic Acid to Organ Failure and Outcome in Critically Ill Pediatric Population

Objective:

To evaluate the clinical and prognostic utility of procalcitonin (PCT), C-reactive protein (CRP), and lactic acid in children admitted to the Pediatric Intensive Care Unit (PICU) of a university teaching hospital.

Materials and Methods:

Medical records of children (1 month–16 years) tested for serum PCT at the time of admission in the PICU of our hospital from July 1, 2013, to January 15, 2015, were reviewed. Within 24 h of admission, the Pediatric Risk of Mortality Score, blood cultures, white blood cell count, neutrophil counts, serum CRP, plasma lactic acid, and PCT were noted. Patient outcome was assessed at hospital discharge, and the patients were divided into nonsurvivors and survivors.

Results:

A total of 167 children being admitted to the PICU were enrolled. The median age of the study population was 3 years (0–16 years), with 58.6% being males. Nonsurvivors had significantly higher lactic acid (4.7 mmol/L [2.07–7.6]; P < 0.05) than that of the survivors (2 mmol/L [1.3–3]; P < 0.05). In addition, nonsurvivors (94.4%; P < 0.05) had greater incidence of multiple organ dysfunction syndrome (MODS) than that of the survivors (38.05%; P < 0.05). Binary logistic regression showed age, MODS, and lactic acid to be associated with mortality.

Conclusions:

This study found that in comparison to PCT and CRP, high plasma lactic acid levels are associated with the development of all-cause MODS and worse outcome in critically ill children admitted in PICU. Prediction of prognosis based on the lactic acid alone may contribute to improve patient management, but further studies are required to endorse our findings.

Diagnostic and prognostic value of procalcitonin for early intracranial infection after craniotomy

Intracranial infection is a common clinical complication after craniotomy. We aimed to explore the diagnostic and prognostic value of dynamic changing procalcitonin (PCT) in early intracranial infection after craniotomy. A prospective study was performed on 93 patients suspected of intracranial infection after craniotomy. Routine peripheral venous blood was collected on the day of admission, and C reactive protein (CRP) and PCT levels were measured. Cerebrospinal fluid (CSF) was collected for routine biochemical, PCT and culture assessment. Serum and CSF analysis continued on days 1, 2, 3, 5, 7, 9, and 11. The patients were divided into intracranial infection group and non-intracranial infection group; intracranial infection group was further divided into infection controlled group and infection uncontrolled group. Thirty-five patients were confirmed with intracranial infection after craniotomy according to the diagnostic criteria. The serum and cerebrospinal fluid PCT levels in the infected group were significantly higher than the non-infected group on day 1 (P<0.05, P<0.01). The area under curve of receiver operating characteristics was 0.803 for CSF PCT in diagnosing intracranial infection. The diagnostic sensitivity and specificity of CSF PCT was superior to other indicators. The serum and CSF PCT levels have potential value in the early diagnosis of intracranial infection after craniotomy. Since CSF PCT levels have higher sensitivity and specificity, dynamic changes in this parameter could be used for early detection of intracranial infection after craniotomy, combined with other biochemical indicators.

Prognostic markers of meningococcal disease in children: recent advances and future challenges

Meningococcal disease is a life-threatening condition and a major cause of bacterial meningitis and sepsis worldwide. In many fatal cases, meningococcal disease is rapidly progressive and death occurs within hours of the initial symptoms. The early identification of patients at high risk of death would be useful in order to provide aggressive and more personalized clinical management with the proper level of supportive therapy required, contributing to an improvement in the survival rate and reduction in sequelae. The current study aims to review the current published literature about prognostic markers of meningococcal sepsis in children in order to elaborate conclusions and recommendations that could guide clinical practice and further research.

Clinical and Cost-Effectiveness of Procalcitonin Test for Prodromal Meningococcal Disease-A Meta-Analysis

Background

Despite vaccines and improved medical intensive care, clinicians must continue to be vigilant of possible Meningococcal Disease in children. The objective was to establish if the procalcitonin test was a cost-effective adjunct for prodromal Meningococcal Disease in children presenting at emergency department with fever without source.

Methods and Findings

Data to evaluate procalcitonin, C-reactive protein and white cell count tests as indicators of Meningococcal Disease were collected from six independent studies identified through a systematic literature search, applying PRISMA guidelines. The data included 881 children with fever without source in developed countries.The optimal cut-off value for the procalcitonin, C-reactive protein and white cell count tests, each as an indicator of Meningococcal Disease, was determined. Summary Receiver Operator Curve analysis determined the overall diagnostic performance of each test with 95% confidence intervals. A decision analytic model was designed to reflect realistic clinical pathways for a child presenting with fever without source by comparing two diagnostic strategies: standard testing using combined C-reactive protein and white cell count tests compared to standard testing plus procalcitonin test. The costs of each of the four diagnosis groups (true positive, false negative, true negative and false positive) were assessed from a National Health Service payer perspective. The procalcitonin test was more accurate (sensitivity=0.89, 95%CI=0.76-0.96; specificity=0.74, 95%CI=0.4-0.92) for early Meningococcal Disease compared to standard testing alone (sensitivity=0.47, 95%CI=0.32-0.62; specificity=0.8, 95% CI=0.64-0.9). Decision analytic model outcomes indicated that the incremental cost effectiveness ratio for the base case was £-8,137.25 (US $ -13,371.94) per correctly treated patient.

Conclusions

Procalcitonin plus standard recommended tests, improved the discriminatory ability for fatal Meningococcal Disease and was more cost-effective; it was also a superior biomarker in infants. Further research is recommended for point-of-care procalcitonin testing and Markov modelling to incorporate cost per QALY with a life-time model.

Serum levels of procalcitonin as a biomarker for differentiating between sepsis and systemic inflammatory response syndrome in the neurological intensive care unit

We explored the value of procalcitonin (PCT) to differentiate sepsis from systemic inflammatory response syndrome (SIRS), and determine sepsis severity in the neurological intensive care unit (NICU). Blood samples were measured for C-reactive protein (CRP) and PCT levels upon NICU admission, on the day of diagnosis of SIRS or sepsis, and at 3 and 7 days after diagnosis. We found that there were significant differences in serum levels of CRP and PCT as well as Glasgow Coma Scale (GCS) score upon admission between the SIRS and sepsis groups (p<0.05). CRP and white blood cell levels were not significantly different when attempting to differentiate sepsis severity (p>0.05). Multiple comparisons showed that significant differences in serum PCT levels were observed between sepsis and severe sepsis groups, as well as sepsis and septic shock groups (p<0.05). We obtained the highest sensitivity and specificity for SIRS and sepsis with cut-off values of 2 ng/mL for PCT, 44 mg/dL for CRP, and 4 for the GCS. There were no differences in CRP and PCT levels between cerebrovascular disease and non-cerebrovascular disease groups (p>0.05). No differences were found between viral and bacterial meningitis groups (p>0.05). PCT levels are valuable in discriminating sepsis from SIRS and determining sepsis severity in critically ill patients with neurological disease.

Dynamic change of procalcitonin, rather than concentration itself, is predictive of survival in septic shock patients when beyond 10 ng/mL

Procalcitonin (PCT) concentration of greater than 10 ng/mL is compatible for septic shock. Its predictive value for survival is not well established, mainly because of much overlap and variation of PCT in this condition. We hypothesized that dynamic change of PCT, rather than PCT itself, is predictive of hospital survival when greater than 10 ng/mL. Thirty-seven septic shock patients with PCT concentration of greater than 10 ng/mL were enrolled in this prospective cohort study. Patients were divided into survivors (n = 25) and nonsurvivors (n = 12) based on 28-day hospital outcome. Subsequent PCT measurements were taken 5 days after enrollment. Sequential Organ Failure Assessment (SOFA) scores were recorded simultaneously. Dynamic changes of the PCT and SOFA score were defined as the difference between the subsequent and initial measurement. There were no significant differences between survivors and nonsurvivors in age, sex, initial measurement of PCT, and SOFA. All survivors had a decrease in PCT concentration; median decrease was 9.73 ng/mL. All nonsurvivors had an increase in PCT concentration; median increase was 5.95 ng/mL. Significant decrease in PCT concentration (>25%) was observed in all the 25 survivors, whereas there was none in 12 nonsurvivors. Procalcitonin of initial, subsequent measurements, and dynamics significantly correlated with their counterparts of SOFA score. In conclusion, significant decrease in PCT concentration, rather than PCT concentration itself, may be a useful indicator of survival in septic shock patients when PCT concentration is greater than 10 ng/mL. Procalcitonin concentration highly correlated with the SOFA score in septic shock patients even when the PCT concentration is greater than 10 ng/mL.

Diagnostic efficacy of activated partial thromboplastin time waveform and procalcitonin analysis in pediatric meningococcal sepsis

OBJECTIVE

A biphasic activated partial thromboplastin time waveform predicts sepsis and disseminated intravascular coagulation in adults. This has not been previously investigated in children. Our aim is to ascertain whether there are changes in the activated partial thromboplastin time waveform in children with meningococcal disease and to compare its diagnostic use with procalcitonin.

SETTING

Alder Hey Children's National Health Service Foundation Trust, Liverpool, UK.

PATIENTS

Thirty-six children admitted to the hospital for the treatment of suspected meningococcal disease had activated partial thromboplastin time waveform and procalcitonin analysis performed at admission. The light transmittance level at 18 secs was used to quantitate the waveform. Severity of disease was assessed using the Glasgow Meningococcal Septicaemia Prognostic Score, Pediatric Risk of Mortality III score, and the Pediatric Logistic Organ Dysfunction score.

MEASUREMENTS AND MAIN RESULTS

Twenty-four children had proven meningococcal disease, 12 had a presumed viral illness, and 20 control subjects were recruited. Transmittance level at 18 secs was lower in children with meningococcal disease and those with a viral illness (p < .0001) and control subjects (p < .0005). Sensitivity and specificity was 0.91 and 0.96 for transmittance level at 18 secs and 0.92 and 1 for procalcitonin in identifying meningococcal disease. There was a significant difference in procalcitonin between children with meningococcal disease and those with a viral illness and control subjects (p < .0005). A negative correlation was found between transmittance level at 18 secs and length of hospital stay (p < .0001), C-reactive protein (p < .0001), procalcitonin (p < .0001), Glasgow Meningococcal Septicaemia Prognostic Score (p < .01), Pediatric Risk of Mortality III score (p < .0001), and Pediatric Logistic Organ Dysfunction score score (p < .0001).

CONCLUSION

The activated partial thromboplastin time waveform is abnormal in children with meningococcal disease and may be a useful adjunct in the diagnosis and management of sepsis in children.

Procalcitonin as a marker of severe bacterial infection in children in the emergency department

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

Pentraxin 3 and C-reactive protein in severe meningococcal disease

The long pentraxin 3 (PTX3) is an important element of the innate immune system and has potential as a diagnostic tool in inflammatory conditions. We studied PTX3 in patients admitted to an intensive care unit with severe meningococcal disease and compared it with the short pentraxin C-reactive protein (CRP). Twenty-six patients with meningococcal disease were studied, 17 patients presented with meningococcal septic shock (shock group), and 9 patients presented with meningococcal meningitis or bacteremia (no-shock group). Pentraxin 3 and CRP were measured by enzyme-linked immunosorbent assay. High plasma concentrations of PTX3 (median, 579 microg/L) were seen at admission in patients with meningococcal disease. Concentrations were significantly higher in patients with shock compared with patients without shock (medians, 801 and 256 microg/L, respectively; P = 0.006). In contrast, CRP at admission was lower in the shock group as compared with the no-shock group (medians, 58 and 165 mg/L, respectively; P = 0.008). High PTX3 and low CRP concentration at admission discriminated between presence and absence of shock (area under the receiver operating characteristic curve, 0.85; P = 0.007 for PTX3 and area under the receiver operating characteristic curve, 0.84; P = 0.01 for CRP). PTX3 did not correlate with disease severity (pediatric risk of mortality) and days spent in the intensive care unit. PTX3 at admission and PTX3 peak concentration both showed a negative correlation with plasma fibrinogen concentrations. C-reactive protein concentration at admission correlated negatively with disease severity. In conclusion, PTX3 was an early indicator of shock in patients with severe meningococcal disease that followed a pattern of induction distinct from CRP.

Serum procalcitonin at the time of admission to the ICU as a predictor of short-term mortality

OBJECTIVE

This purpose of this study was to determine if serum procalcitonin (PCT) concentration at the time of admission to the ICU is a predictor of all-cause short-term mortality.

DESIGN AND METHODS

This prospective cross-sectional study was conducted over a 16-month period with 86 consecutive critically ill patients. The semi-quantitative PCT-Q test was performed and APACHE II scores and C-reactive protein (CRP) concentrations were determined within 24 h of admission.

RESULTS

PCT-Q test value was a better predictor of all-cause short-term mortality than CRP value or APACHE II score. PCT > or = 10 ng/mL was highly and independently correlated with mortality. Use of PCT-Q > or = 10 ng/mL was superior to use of APACHE II > or = 25 or CRP > or = 10 mg/dL as a predictor of poor outcome.

CONCLUSIONS

A PCT-Q value > or = 10 ng/mL obtained at the time of admission to the ICU is a strong predictor of short-term mortality.

Comparison of WBC, ESR, CRP and PCT serum levels in septic and non-septic burn cases

Diagnosis of sepsis is difficult, particularly in cases of burn where signs of sepsis may be present in the absence of a real infection. This study compared serum levels of procalcitonin (PCT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and white blood cell (WBC) among 60 burned people with and without infection, in order to assess the value of the information for diagnosis of sepsis. A significantly higher PCT level was observed in the septic group compared to those without sepsis (8.45+/-7.8 vs. 0.5+/-1.0, respectively, p<0.001); no significant differences were found in CRP or WBC levels, neutrophil count or ESR. The area under the receiver operating characteristics curve in the diagnosis of sepsis was 0.97 for PCT (p<0.001) with sensitivity of 100% and specificity of 89.3%. Non-survivors had a mean PCT level significantly higher than that of survivors. Thus the serum PCT level was a highly efficient laboratory parameter for the diagnosis of severe infectious complications after burn, but WBC, neutrophil, ESR and CRP levels were of little value.

Procalcitonin assay in systemic inflammation, infection, and sepsis: clinical utility and limitations

OBJECTIVE

The use of procalcitonin (ProCT) as a marker of several clinical conditions, in particular, systemic inflammation, infection, and sepsis, will be clarified, and its current limitations will be delineated. In particular, the need for a more sensitive assay will be emphasized. For these purposes, the medical literature comprising clinical studies pertaining to the measurement of serum ProCT in various clinical settings was examined.

DATA SOURCE AND SELECTION

A PubMed search (1965 through November 2007) was conducted, including manual cross-referencing. Pertinent complete publications were obtained using the MeSH terms procalcitonin, C-reactive protein, sepsis, and biological markers. Textbook chapters were also read and extracted.

DATA EXTRACTION AND SYNTHESIS

Available clinical and other patient data from these sources were reviewed, including any data relating to precipitating factors, clinical findings, associated illnesses, and patient outcome. Published data concerning sensitivity, specificity, and reproducibility of ProCT assays were reviewed.

CONCLUSIONS

Based on available data, the measurement of serum ProCT has definite utility as a marker of severe systemic inflammation, infection, and sepsis. However, publications concerning its diagnostic and prognostic utility are contradictory. In addition, patient characteristics and clinical settings vary markedly, and the data have been difficult to interpret and often extrapolated inappropriately to clinical usage. Furthermore, attempts at meta-analyses are greatly compromised by the divergent circumstances of reported studies and by the sparsity and different timing of the ProCT assays. Although a high ProCT commonly occurs in infection, it is also elevated in some noninfectious conditions. Thus, the test is not a specific indicator of either infection or sepsis. Moreover, in any individual patient, the precipitating cause of an illness, the clinical milieu, and complicating conditions may render tenuous any reliable estimations of severity or prognosis. It also is apparent that even a febrile septic patient with documented bacteremia may not necessarily have a serum ProCT that is elevated above the limit of functional sensitivity of the assay. In this regard, the most commonly applied assay (i.e., LUMItest) is insufficiently sensitive to detect potentially important mild elevations or trends. Clinical studies with a more sensitive ProCT assay that is capable of rapid and practicable day-to-day monitoring are needed and shortly may be available. In addition, investigations showing that ProCT and its related peptides may have mediator relevance point to the need for evaluating therapeutic countermeasures and studying the pathophysiologic effect of hyperprocalcitonemia in serious infection and sepsis.