How to use C-reactive protein

Biomarkers for Serious Bacterial Infections in Febrile Children

Febrile infections in children are a common cause of presentation to the emergency department (ED). While viral infections are usually self-limiting, sometimes bacterial illnesses may lead to sepsis and severe complications. Inflammatory biomarkers such as C reactive protein (CRP) and procalcitonin are usually the first blood exams performed in the ED to differentiate bacterial and viral infections; nowadays, a better understanding of immunochemical pathways has led to the discovery of new and more specific biomarkers that could play a role in the emergency setting. The aim of this narrative review is to provide the most recent evidence on biomarkers and predictor models, combining them for serious bacterial infection (SBI) diagnosis in febrile children. Literature analysis shows that inflammatory response is a complex mechanism in which many biochemical and immunological factors contribute to the host response in SBI. CRP and procalcitonin still represent the most used biomarkers in the pediatric ED for the diagnosis of SBI. Their sensibility and sensitivity increase when combined, and for this reason, it is reasonable to take them both into consideration in the evaluation of febrile children. The potential of machine learning tools, which represent a real novelty in medical practice, in conjunction with routine clinical and biological information, may improve the accuracy of diagnosis and target therapeutic options in SBI. However, studies on this matter are not yet validated in younger populations, making their relevance in pediatric precision medicine still uncertain. More data from further research are needed to improve clinical practice and decision making using these new technologies.

The Role of Pentraxin 3 in Gastrointestinal Cancers

Gastrointestinal cancers have become a huge problem worldwide as the number of new cases continues to increase. Due to the growing need to explore new biomarkers and therapeutic targets for the detection and treatment of cancerous lesions, we sought to elucidate the role of Pentraxin-3 in the progression of cancerous lesions, as it is involved in the process of angiogenesis and inflammation. Statistically significant changes in the concentration of this parameter have emerged in many gastrointestinal cancer patients. Moreover, it is related to the advancement of cancer, as well as processes leading to the development of those changes. In the case of studies concerning tissue material, both increased and decreased tissue expression of the tested parameter were observed and were dependent on the type of cancer. In the case of cell lines, both human and animal, a significant increase in Pentraxin 3 gene expression was observed, which confirmed the changes observed at the protein level. In conclusion, it can be assumed that PTX3, both at the level of gene expression and protein concentrations, is highly useful in the detection of gastrointestinal cancers, and its use as a biomarker and/or therapeutic target may be useful in the future.

C-reactive protein point-of-care testing and complementary strategies to improve antibiotic stewardship in children with acute respiratory infections in primary care

This paper provides the perspective of an international group of experts on the role of C-reactive protein (CRP) point-of-care testing (POCT) and complementary strategies such as enhanced communication skills training and delayed prescribing to improve antibiotic stewardship in the primary care of children presenting with an acute illness episode due to an acute respiratory tract infection (ARTI). To improve antibiotics prescribing decisions, CRP POCT should be considered to complement the clinical assessment of children (6 months to 14 years) presenting with an ARTI in a primary care setting. CRP POCT can help decide whether a serious infection can be ruled out, before deciding on further treatments or management, when clinical assessment is unconclusive. Based on the evidence currently available, a CRP value can be a valuable support for clinical reasoning and facilitate communication with patients and parents, but the clinical assessment should prevail when making a therapy or referral decision. Nearly half of children tested in the primary care setting can be expected to have a CRP value below 20 mg/l, in which case it is strongly suggested to avoid prescribing antibiotics when the clinical assessment supports ruling out a severe infection. For children with CRP values greater than or equal to 20 mg/l, additional measures such as additional diagnostic tests, observation time, re-assessment by a senior decision-maker, and specialty referrals, should be considered.

Early signaling of inflammation in patients following traumatic injury with accurately estimated time of injury by profiling C-reactive protein levels

BACKGROUND

Despite its widespread use, the precise dynamics of CRP response in clinical practice remain poorly defined. We employed a novel quadratic model to explore the time-course analysis of CRP values in trauma patients with known precise time of injury.

METHODS

Relevant data on all adult patients admitted to our hospital following traumatic incidents between January 1st 2010 to December 31, 2020 were retrospectively collected. Those with a documented time of injury and who underwent CRP evaluation within the first 24 h since injury were studied.

RESULTS

Based on the findings from our annual health check-up center, we established a reference upper normal CRP value of 12.99 mg/L. Within the first 7 h after injury, the CRP levels of 8-9% of the 1545 study patients exceeded the reference threshold. The proportion of patients with CRP levels > 12.99 mg/L increased to 18.5% at 8-9 h later and rose sharply to 91.6% at 22-24 h later. Our quadratic model yielded the equation: CRP = 5.122-0.528xTime + 0.139xTime 2. It accounted for > 40% of the variance in CRP levels (R2 = 42.4%).

CONCLUSIONS

Clear and prominent CRP elevations following atraumatic event are detected only 9-12 h following the insult. This novel finding has crucial implications for accurate CRP assessment of inflammatory responses to physical injuries.

COVID-19 Biomarkers at the Crossroad between Patient Stratification and Targeted Therapy: The Role of Validated and Proposed Parameters

Clinical knowledge about SARS-CoV-2 infection mechanisms and COVID-19 pathophysiology have enormously increased during the pandemic. Nevertheless, because of the great heterogeneity of disease manifestations, a precise patient stratification at admission is still difficult, thus rendering a rational allocation of limited medical resources as well as a tailored therapeutic approach challenging. To date, many hematologic biomarkers have been validated to support the early triage of SARS-CoV-2-positive patients and to monitor their disease progression. Among them, some indices have proven to be not only predictive parameters, but also direct or indirect pharmacological targets, thus allowing for a more tailored approach to single-patient symptoms, especially in those with severe progressive disease. While many blood test-derived parameters quickly entered routine clinical practice, other circulating biomarkers have been proposed by several researchers who have investigated their reliability in specific patient cohorts. Despite their usefulness in specific contexts as well as their potential interest as therapeutic targets, such experimental markers have not been implemented in routine clinical practice, mainly due to their higher costs and low availability in general hospital settings. This narrative review will present an overview of the most commonly adopted biomarkers in clinical practice and of the most promising ones emerging from specific population studies. Considering that each of the validated markers reflects a specific aspect of COVID-19 evolution, embedding new highly informative markers into routine clinical testing could help not only in early patient stratification, but also in guiding a timely and tailored method of therapeutic intervention.

Value of combined detection of serum amyloid A, C-reactive protein and procalcitonin in differential diagnosis of respiratory tract infection in children of China

OBJECTIVE

To explore the diagnostic value of combined detection of serum amyloid A (SAA), C-reactive protein (CRP) and procalcitonin (PCT) in children with bacteria or non-bacterial respiratory tract infection.

METHODS

200 children with respiratory tract infections diagnosed in our hospital were included in the study. According to the results of the aetiological examination, they were divided into bacterial infection group and non-bacterial infection group. At the same time, 100 healthy children admitted to the hospital for physical examination during the same period were selected as the healthy subjects control group. Changes in serum SAA, PCT and CRP in three groups were compared. Comparison of a positive rate of the single index and combined detection were performed. Children with bacterial infections were treated with conventional antibiotics. The changes in serum SAA, PCT and CRP in the infection group before and after treatment were compared. The efficacy of SAA, PCT and CRP alone and in combination was compared.

RESULTS

The serum SAA, PCT and CRP levels in the bacterial infection group were higher than those in the non-bacterial infection group and healthy children, and the differences were statistically significant. The positive detection rates and combined detection rates of serum SAA, PCT and CRP in the bacterial infection group were higher than those in the non-bacterial infection group and the healthy subject's control group. After conventional antibiotic treatment, serum SAA, PCT and CR levels in children with bacterial infection were significantly decreased.

CONCLUSION

The combined detection based on SAA, CRP and PCT can effectively identify and diagnose respiratory tract infection in children, providing a certain reference for the promotion of the diagnostic scheme. Key messagesSerum SAA, PCT and CRP were highly expressed in children with respiratory tract infection, and the expression level was the highest in children with bacterial pneumonia.The combined detection of serum SAA, CRP and PCT indicators have higher diagnostic efficiency and can effectively make a differential diagnosis of respiratory tract infection in children.

Effect of a Hemodialysis Session on Markers of Inflammation and Endotoxin

Background

People receiving hemodialysis (HD) treatment have higher cardiovascular morbidity and mortality, ascribed to an increased prevalence of traditional cardiovascular risk factors. However, the role of nontraditional risk factors, such as inflammation, has become increasingly recognized. The origin of this inflammation remains elusive and one putative cause is elevated levels of circulating bacterial endotoxin.

Methods

In this study, serum concentrations of endotoxin and inflammatory biomarkers, including high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), interleukin-1β (IL1β), ferritin and tumor necrosis factor (TNF), were measured in 30 adults receiving HD and 10 healthy individuals without kidney disease. In people receiving HD, samples were collected immediately before dialysis (preHD), after dialysis (postHD), and 48 hours after (postHD_48hrs).

Results

Endotoxin was detectable in only 1 of 90 samples analyzed. There were no significant differences in serum hsCRP, IL1β, and IL6 levels, before and after dialysis. Serum TNF levels decreased significantly from 30.9 (8.0, 39.5) pg/mL preHD to 13.9 (8.5, 17.3) pg/mL post-HD (p=0.002) and then increased back to 27.37 (14.5, 35) pg/mL 2 days later (p < 0.001). Ferritin increased from 1153 ng/mL (782, 1458) preHD to 1313 ng/mL (657, 1638) post HD (p < 0.001) and then decreased back to 1186 ng/mL (754, 1597) (p=0.66) postHD_48hrs. Compared to controls, people receiving HD had significantly elevated levels of hsCRP [6.16 mg/L (2.1, 16.8) vs. 1.1 mg/L (0.81, 3.63) p=0.015], IL1β [1.5 pg/mL (0.05, 2.51) vs. 0.5 pg/mL (1.81, 2.95) p ≤ 0.001], and ferritin [1153 (782, 1458) vs. 132.9 (111, 257) ng/mL p ≤ 0.001], but comparable levels of in IL6 [6.15 pg/mL (4.82, 9.12) vs. 7.49 pg/mL (4.56, 10.39), p=0.77] and TNF [27.35 pg/mL ± 17.48 vs. 17.87 pg/mL ± 12.28, p < 0.12]. In conclusion, people on HD have elevated levels of inflammatory biomarkers, which are not associated with endotoxemia (which is rare) or the dialysis procedure.

Correlation Analysis between Hemoglobin and C-Reactive Protein in Patients Admitted to an Emergency Unit

Anemia and inflammation are common clinical conditions in emergency departments. This study explored a cohort of patients admitted to the emergency department with a particular interest in determining the frequency of anemia and inflammation and the association between hemoglobin (Hb) and C-reactive protein (CRP) concentrations. The study included 125 patients categorized according to their demographic (gender and age) and clinical condition (Hb and CRP concentrations, pathological background, and diagnostic). We found that anemia and inflammation were simultaneously present in 36.0% of the cohort, reaching 67.0% in patients that were subsequently hospitalized. The Hb level was significantly lower in patients with elevated concentration of CRP when compared to individuals with normal CRP levels (11.58 ± 2.23 vs. 13.25 ± 1.80, p = 0.001); furthermore, we found a significantly negative correlation between Hb concentration and the CRP level (rs = −0.42, p < 0.001). The linear regression model applied to the cohort showed that CRP levels explain 15% of Hb variations. The sensitivity of the CRP/Hb ratio (cut-off = 1.32) as a predictor of hospitalization was 80.0%, with a specificity of 68.4% for all patients. These findings confirmed the prevalence of anemia and inflammation and identified a moderate but significant association between Hb and serum CRP in a heterogeneous group of patients admitted to the emergency department.

Infants 21-90 days presenting with a possible serious bacterial infection - are evaluation algorithms from high income countries applicable in the South African public health sector?

BACKGROUND

Young infants with a possible serious bacterial infection (SBI) are a very common presentation to emergency centres (ECs). It is often difficult to distinguish clinically between self-limiting viral infections and an SBI. Available evaluation algorithms to assist clinicians are mostly from high-income countries. Data to inform clinical practice in low- and middle-income countries are lacking.

OBJECTIVES

To determine the period prevalence of SBI and invasive bacterial infection (IBI) and describe current practice in the assessment and management of young infants aged 21-90 days presenting with a possible SBI to a Paediatric Emergency centre (PEC) in Cape Town, South Africa.

METHODS

A retrospective cross-sectional review of infants 21-90 days old presenting to the Tygerberg Hospital PED between 1 January 2016 and 31 May 2016.

RESULTS

A total of 248 infants 21-90 days were included in the study. Sixty-two patients (25%, 95% CI 20-30) had an SBI and 13 (5.2%, 95% CI 3-8) had an IBI. One hundred and sixty-five infants had a possible SBI based on WHO IMCI criteria. The sensitivity of the WHO IMCI criteria in detecting SBI was 82.3% (95% CI 70.5-90.8) and the specificity 38.7% (95% CI 31.7-46.1). More than half (51.2%) of the infants received antibiotics within the 48 h prior to presentation, of which 33.5% included intramuscular injection of Ceftriaxone. Only 20 (8.0%) patients in this age group were discharged home after initial evaluation. A significant relationship was noted between fever and the risk of SBI (p-value 0.010) and IBI (p-value 0.009). There also appeared to be a significant relationship between nutritional status and IBI (p-value 0.013).

CONCLUSION

Period prevalence of SBI and IBI was higher compared to that published in the literature. Validated evaluation algorithms to stratify risk of SBI are needed to assist clinicians in diagnosing and managing infants appropriately in low- and middle-income settings.