Procalcitonin, a marker of bacterial infection

Establishment of a risk prediction model for bowel necrosis in patients with incarcerated inguinal hernia

INTRODUCTION

Incarceration occurred in approximately 5% to 15% of inguinal hernia patients, with around 15% of incarcerated cases progressing to intestinal necrosis, necessitating bowel resection surgery. Patients with intestinal necrosis had significantly higher mortality and complication rates compared to those without necrosis.The primary objective of this study was to design and validate a diagnostic model capable of predicting intestinal necrosis in patients with incarcerated groin hernias.

METHODS

We screened the clinical records of patients who underwent emergency surgery for incarcerated inguinal hernia between January 1, 2015, and December 31, 2022. To ensure balanced representation, the enrolled patients were randomly divided into a training set (n = 180) and a validation set (n = 76) using a 2:1 ratio. Logistic regression analysis was conducted using the rms package in R software, incorporating selected features from the LASSO regression model, to construct a predictive model.

RESULTS

Based on the results of the LASSO regression analysis, a multivariate logistic regression model was developed to establish the predictive model. The predictors included in the model were Abdominal effusion, Hernia Sac Effusion, and Procalcitonin. The area under the receiver operating characteristic (ROC) curve for the nomogram graph in the training set was 0.977 (95% CI = 0.957-0.992). In the validation set, the AUC for the nomogram graph was 0.970. Calibration curve and decision curve analysis (DCA) verified the accuracy and practicability of the nomogram graph in our study.

CONCLUSION

Bowel necrosis in patients with incarcerated inguinal hernia was influenced by multiple factors. The nomogram predictive model constructed in this study could be utilized to predict and differentiate whether incarcerated inguinal hernia patients were at risk of developing bowel necrosis.

Serum Inflammatory Biomarkers in the Diagnosis of Periprosthetic Joint Infections

Accurate preoperative diagnosis of periprosthetic joint infections (PJIs) can be very challenging, especially in patients with chronic PJI caused by low-virulence microorganisms. Serum parameters, such as serum C-reactive protein (CRP) or the erythrocyte sedimentation rate (ESR), are—among other diagnostic test methods—widely used to distinguish septic from aseptic failure after total hip or knee arthroplasty and are recommended by the AAOS in the preoperative setting. However, they are systemic parameters, and therefore, unspecific. Nevertheless, they may be the first and occasionally the only preoperative indication, especially when clinical symptoms are lacking. They are easy to obtain, cheap, and are available worldwide. In the last decade, different novel serum biomarkers (percentage of neutrophils, neutrophils to lymphocytes ratio, platelet count to mean platelet volume ratio, fibrinogen, D-Dimer, Il-6, PCT) were investigated to find a more specific and accurate serum parameter in the diagnosis of PJI. This article reviews the diagnostic value of established (serum CRP, ESR, WBC) and ‘novel’ serum inflammatory biomarkers (fibrinogen, D-dimer, interleukin-6 (IL-6), procalcitonin, percentage of neutrophils (%N), neutrophils to lymphocytes ratio (NLR), platelet count to mean platelet volume ratio (PC/mPV)) for the preoperative diagnosis of periprosthetic joint infections.

One-step-immunoassay of procalcitonin enables rapid and accurate diagnosis of bacterial infection

Procalcitonin (PCT) (i.e. a precursor of calcitonin) attracts much attention as a reliable biomarker of bacterial infections because its concentration increases rapidly in the blood when bacterial infections occur in the body. Sepsis may occur due to indiscriminate and vigorous proliferation of infectious bacteria, and accordingly early diagnosis and treatment of bacterial infection are of crucial importance. However, current diagnostic methods for sepsis suffer from long assay time, multiple and complex assay steps, inaccuracy, and requirement of analytical equipments. The goal of this study is to develop an advanced one-step-immunoassay that enables quick and accurate diagnosis of sepsis through measuring the PCT concentration in patient sera, which is based on self-enhancement of optical detection signals from large gold particles (i.e. clusters of gold nanoparticles) that are formed on the agglomerates of PCT-bound 3-dimensional (3D) probes. The 3D probe is constructed through attaching polyclonal anti-PCT antibodies (IgGs) to the surface of a modified hepatitis B virus (HBV) capsid, where both tandem repeats of the B domain of Staphylococcal protein A (SPA_B) and the hexa-histidine tag are inserted into each HBV core protein (i.e. subunit of HBV capsid). That is, anti-PCT IgGs are attached via strong interaction between the Fc region and surface-exposed SPA_B. Furthermore, hook effect-free and PCT concentration-dependent optical signals were consistently generated by adding both bovine serum albumin (BSA) and nickel ions to patient sera and also by optimally adjusting the 3D probe concentration. Compared to conventional chemiluminescent microparticle immunoassay (CMIA) showing poor linearity of detection signals, this novel immunoassay accurately detected PCT with good linearity between PCT concentrations and optical signals in a wide range of PCT concentrations (0.05–200 ng mL⁻¹) and also showed a sufficiently low limit of detection, resulting in 100% sensitivity and 100% specificity when tested with 30 sepsis patients and 30 healthy individuals.

An advanced one-step-immunoassay enables quick and accurate diagnosis of sepsis with generation of clear optical signals in assay solution, which is based on sensitive detection of procalcitonin in patient sera.

Utility of Routine Laboratory Biomarkers to Detect COVID-19: A Systematic Review and Meta-Analysis

No routine laboratory biomarkers perform well enough in diagnosing COVID-19 in isolation for them to be used as a standalone diagnostic test or to help clinicians prioritize patients for treatment. Instead, other diagnostic tests are needed. The aim of this work was to statistically summarise routine laboratory biomarker measurements in COVID-19-positive and -negative patients to inform future work. A systematic literature review and meta-analysis were performed. The search included names of commonly used, routine laboratory tests in the UK NHS, and focused on research papers reporting laboratory results of patients diagnosed with COVID-19. A random effects meta-analysis of the standardized mean difference between COVID-19-positive and -negative groups was conducted for each biomarker. When comparing reported laboratory biomarker results, we identified decreased white blood cell, neutrophil, lymphocyte, eosinophil, and platelet counts; while lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase were elevated in COVID-19-positive compared to COVID-19-negative patients. Differences were identified across a number of routine laboratory biomarkers between COVID-19-positive and -negative patients. Further research is required to identify whether routine laboratory biomarkers can be used in the development of a clinical scoring system to aid with triage of patients.

Evaluation and comparison of serum procalcitonin and heparin-binding protein levels as biomarkers of bacterial infection in cats

OBJECTIVES

As bacterial infection can lead to sepsis and high mortality, early and easy diagnosis of sepsis can improve survival. In cats, the diagnosis of systemic bacterial infection is quite challenging, and, usually, non-specific markers for inflammation are employed. In humans, procalcitonin, heparin-binding protein and absolute neutrophil count are biomarkers that are studied in bacterial infections and sepsis owing to their high sensitivity and specificity.

METHODS

A total of 56 cats were categorised into 16 healthy cats and 40 bacterially infected cats, diagnosed by various examinations. In all cats, serum procalcitonin and heparin-binding protein levels were measured using ELISA and an absolute neutrophil count was performed.

RESULTS

The median values of procalcitonin levels and absolute neutrophil count were significantly higher in the infection group than in the normal group, but heparin-binding protein levels were not. A procalcitonin level >366 pg/ml was a better biomarker of bacterial infection than heparin-binding protein and absolute neutrophil count (sensitivity: 67.5%; specificity: 93.8%). Procalcitonin was not correlated with heparin-binding protein (r = 0.213, P = 0.115) and absolute neutrophil count (r = 0.393, P = 0.003).

CONCLUSIONS AND RELEVANCE

High procalcitonin levels in cats were associated with bacterial infection. Hence, procalcitonin could be a valuable marker for diagnosing bacterial infections in cats.

Sepsis and ECMO

Sepsis is being recognized as an important complication of extracorporeal membrane oxygenation (ECMO) and its presence is a poor prognostic marker and increases the overall mortality. The survival rate differs in the various types of cannulation techniques. Adult patients with prolonged duration of ECMO constitute the major risk population. Ventilator-associated pneumonia and bloodstream infections form the main sources of sepsis in these patients. It is important to know the most common etiological agents for sepsis in ECMO, which varies partly with the local epidemiology of the hospitals. A high index of suspicion, drawing adequate volumes for blood culture and early and timely administration of appropriate empirical antimicrobials can substantially decrease the morbidity and mortality in this high-risk population. The dosing of antimicrobials is influenced by the pharmacological variations on ECMO machine and is an important consideration. Infection control practices are of paramount importance and need to be followed meticulously to prevent sepsis in ECMO.

Procalcitonin as a Predictive Marker for Bacteremia in Children With a Central Line and Fever

OBJECTIVES

Unnecessary use of antibiotics is an increasing problem. In this study, we sought to determine the diagnostic accuracy of procalcitonin in predicting bacteremia in children with a central line and fever, and we sought to determine optimal cutoff values to maximize sensitivity and specificity. This is the largest study to date in which procalcitonin is examined as a predictive marker of bacteremia in pediatric patients with a central line and fever.

METHODS

We conducted a retrospective cohort study of children aged 0 to 23 years with a central line and fever of 38°C who had procalcitonin and blood cultures drawn before initiation of antibiotics and had no other identified bacterial infection. Patients were also prospectively monitored via a custom-built electronic medical record dashboard for eligibility.

RESULTS

There were 523 patients and >2500 procalcitonin values reviewed for eligibility. Of these, 169 (47%) patients and 335 blood cultures with procalcitonin were included. There were 94 (28%) positive bacterial blood cultures and 241 (72%) negative bacterial blood cultures. In bacteremic cultures, the mean procalcitonin level was 9.96 ± 15.96 ng/mL, and the median procalcitonin level was 4.85 ng/mL (interquartile range 18.5). In nonbacteremic cultures, the mean procalcitonin level was 1.23 ± 10.37 ng/mL, and the median procalcitonin level was 0.3 ng/mL (interquartile range 0.7). A receiver operating characteristic analysis indicated a procalcitonin level of ≥0.6 ng/mL as the best cutoff point that produced a sensitivity of 85.6% and a specificity of 65.7% (area under the curve 0.85).

CONCLUSIONS

Procalcitonin is a sensitive biomarker in predicting bacteremia in children with a central line and fever.

Value of procalcitonin for diagnosing perioperative pneumonia, urinary infections and superficial surgical site infections in patients undergoing primary hip and knee arthroplasty

Serum procalcitonin (PCT) levels may be helpful for the diagnosis of infections during the perioperative period of arthroplasty. However, there is much debate in the literature regarding the appropriate cut-off value for different types of surgery and local bacterial infection. The present study aimed to evaluate serum PCT levels in patients undergoing arthroplasty and to determine the cut-off value that may represent perioperative pneumonia, urinary infections and superficial surgical site infections. The present retrospective study included a total of 500 patients treated between July 2014 and August 2015. The case group contained 25 patients with perioperative infections (pneumonia, urinary and superficial surgical site infections), and the control group contained 25 patients without any post-surgical complications. Serum levels of PCT and white blood cells (WBC) were measured pre-operatively (D0) and at post-operative D4, D6 and D8, and the sensitivity, specificity and predictive value of these parameters were assessed. Regarding the comparison of the mean PCT levels between the case and the control group, a significant difference was seen at D8 (P=0.007), while no significant differences were observed at D0 (P=0.010), D4 (P=0.069) and D6 (P=0.093). No statistically significant differences in WBC levels between groups were observed for (P>0.01). In the control group, the PCT levels at D4 (0.062±0.020 ng/ml) were 2-fold of the mean baseline value, followed by a decrease until D6 (0.051±0.019 ng/ml) and a return close to the normal range by D8 (0.032±0.015 ng/ml). The PCT levels in the case group had rapidly increased on D4 (0.510±1.208 ng/ml). In contrast to the control group, they continuously increased on D6 (0.527±1.360 ng/ml) and D8 (0.686±1.117 ng/ml). From a clinical point of view, infection events were indicated in these patients during post-operative follow-up. For PCT, the area under the receiver operating characteristic curve (AUC) was 0.978 [95% confidence interval (CI), 0.933-1.022], and for WBC, the AUC was 0.562 (95% CI, 0.398-0.0.726). Based on the above data, the PCT value was a significant predictor of infection (AUC>0.9). For PCT, the cut-off point of 0.0995 ng/ml was associated with a sensitivity of 96% and a specificity of 100%. However, WBC were not a significant predictor of infection (0.5<AUC<0.7), and the cut-off value of 7.05×10⁹/l was associated with a sensitivity of 64% and a specificity of 44%. In conclusion PCT was found to be a promising marker for diagnosing bacterial infections post-arthroplasty due to its high specificity. Based on the sensitivity and the specificity, detecting PCT may be more valuable than using WBC in the diagnosis of sepsis-associated pathological changes in the perioperative period.

Procalcitonin: The marker of pediatric bacterial infection

Timely recognition of systemic bacterial infections in pediatric care setting is the basis for effective treatment and control. This review provides an overview of procalcitonin (PCT) as an early marker for the detection of severe, invasive bacterial infection in children. Almost all articles on biochemical property and clinical studies in PubMed and Scopus databases regarding their use in pediatric infections and the use of PCT as a marker of bacterial infections were examined. Various methods and analyzers are currently available for the evaluation of PCT. Employment of PCT in the identification of neonatal bacterial infection is a complex process in some conditions. Age specific cut-off, underlying syndrome, and maternal antibiotics usage should be considered when PCT is to be applied in neonates. PCT might be false-negative in these conditions. However, if used appropriately, it can lead to a higher specificity than other immunologic markers. Due to its correlation with the severity of infection, PCT can consequently be used as a prognostic indicator especially for sepsis and urinary tract infection. It is, therefore, a practical supplementary means for the identification of bacterial infections in pediatric health settings.

The relationship between procalcitonin and thyroid autoantibodies in patients with autoimmune thyroiditis

BACKGROUND

The aim of this study is to investigate the serum levels of procalcitonin and its association with autoantibodies in patients with euthyroid Hashimoto's thyroiditis.

METHODS

A total of 80 participants were included in the study; 40 of which were newly diagnosed with Hashimoto's thyroiditis, aged over 18, and 40 of which were healthy volunteers. The serum levels of procalcitonin were measured by enzyme-linked immunosorbent assay kit. Thyroid function tests were analyzed in hormone laboratory with Electro-chemiluminescence immunoassay.

RESULTS

Hashimoto's thyroiditis patients had higher median procalcitonin levels than those of the control group (34.3 pg/mL vs 27.8 pg/mL respectively; P=.037). Also, male patients had higher median procalcitonin levels as compared to female patients (37 pg/mL vs 27 pg/mL respectively; P=.013). In the Hashimoto's thyroiditis group, procalcitonin level was positively correlated with anti-thyroglobulin and anti-thyroid peroxidase levels (r=.559, P<.001; r=634, P<.001, respectively). The procalcitonin and anti-thyroid peroxidase levels were identified to be an independent predictor in diagnosis of Hashimoto's thyroiditis.

CONCLUSIONS

The fact that procalcitonin was found to be correlated with thyroid autoantibodies and found to be an independent risk factor for Hashimoto's thyroiditis in the regression analysis in the framework of this study urges us to think that procalcitonin may be associated with the autoimmunity.

Serum Procalcitonin Level Reflects the Severity of Cellulitis

Background

Cellulitis is a common bacterial infection of the superficial skin. Procalcitonin is one of the precursor proteins of calcitonin, its levels are elevated in bacterial infection, and it has been established as a diagnostic marker for severe bacterial infections.

Objective

This study evaluated the clinical usefulness of procalcitonin for predicting disease severity and prognosis of cellulitis.

Methods

We reviewed the medical records of 160 patients diagnosed with cellulitis in the past 3 years. Body temperature, procalcitonin, white blood cell (WBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels were measured on their first day of admission. The associations of procalcitonin, WBC, ESR, and CRP with the body temperature and the number of hospitalized days were assessed.

Results

Procalcitonin, WBC, and CRP showed a positive correlation with body temperature. In addition, procalcitonin, WBC, ESR, and CRP showed a positive correlation with number of hospitalized days (p<0.05).

Conclusion

In patients diagnosed with cellulitis, proclacitonin was a helpful parameter to indicate the severity of disease and also a useful predictor of prognosis.

Procalcitonin as a marker of respiratory disorder in neonates

BACKGROUND

Serum procalcitonin (PCT) increases in various respiratory disorders such as acute respiratory distress syndrome. Elevated PCT is also observed in healthy neonates. In this study, we investigated whether PCT is a good marker of respiratory disorder in neonates.

METHODS

A total of 155 neonates with or without respiratory disorder, were eligible for the study. PCT was measured on electrochemiluminescence immunoassay. Each neonate was allocated to the non-respiratory disorder (control) group (n = 95), or a respiratory disorder group (n = 60). PCT was compared between the groups, and association with other markers, including C-reactive protein (CRP) and white blood cell (WBC) count, was analyzed.

RESULTS

Of the 60 neonates in the respiratory disorder group, 39, 10, five, one, two, two, and one neonates had transient tachypnea of the newborn, respiratory distress syndrome, air leak syndrome, meconium aspiration syndrome, 18-trisomy, neonatal asphyxia, and congenital diaphragmatic hernia, respectively. Mean PCT, CRP and WBC count in the respiratory disorder group were 9.01 ng/mL, 0.26 mg/dL, and 16,100 cells/μL, respectively. The area under the curve obtained for PCT in distinguishing between the respiratory disorder and control groups was 0.85 (sensitivity, 66.7%; specificity, 93.0%; optimum cut-off, 3.73 ng/mL), that for CRP was 0.72 (sensitivity, 75.0%; specificity, 64.6%; optimum cut-off, 0.14 mg/dL), and for WBC it was 0.44 (sensitivity, 60.0%; specificity, 29.6%; optimum cut-off, 15,000 cells/μL).

CONCLUSIONS

PCT is more susceptible, as a diagnostic parameter of infection, to the effect of respiratory disturbance than CRP and WBC.

Bedside procalcitonin and acute care

Procalcitonin (PCT) is a 116-amino acid protein with a sequence identical to that of the prohormone of calcitonin. Under normal conditions a specific protease cleaves all PCT to calcitonin, katacalcin and an N-terminal residue and hence in healthy individual PCT levels are either too low or undetectable. However, in severe bacterial infections or septic conditions, intact PCT is found in the blood and the concentrations of PCT may reach up to 1000 ng/ml. Point-of-care testing (POCT) is an important diagnostic tool used in various locations in the hospital, especially in intensive care unit (ICU), the operating room (OR), and emergency set-ups. Laboratory test results are often pivotal to fast decisions in majority of areas where patients are critical. Testing provides physicians with valuable knowledge about the emergency in the patients so that appropriate therapeutic interventions can be made quickly. Early detection of rising PCT levels has great significance and helps in diagnosing and managing the patients quickly. This review highlights various facts about PCT in point-of-care scenarios.

Serum procalcitonin levels in patients with ankylosing spondylitis

AIM

Procalcitonin is a marker of bacterial and fungal infection and sepsis. The present study evaluated the relationship between serum procalcitonin levels and disease activity in patients with ankylosing spondylitis (AS).

METHOD

A total of 61 patients who met the 1984 New York criteria for AS were studied. Twenty-four age- and sex-matched healthy volunteers were recruited to this study as a control group. Disease activity was assessed by the Bath AS Disease Activity Index (BASDAI). The functional status of patients was evaluated by the Bath AS Functional Index (BASFI). Spinal mobility was measured by the Bath AS Metrology Index (BASMI). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and serum procalcitonin levels were measured.

RESULTS

Thirty patients were on anti-tumor necrosis factor-alpha treatment and 31 patients were on conventional treatment. Seventeen (28%) of the AS patients were active (BASDAI > 4) and 44 (72%) of the AS patients were in remission. The median ESR was 14 (34-6) mm/h and 4 (7-2) mm/h (P < 0.001) for the patient and control groups, respectively. The median CRP level was 0.91 (2.72-0.37) mg/dL and 0.15 (0.25-0.07) mg/dL in the patient and control groups, respectively (P < 0.001). Median BASDAI, BASFI and BASMI scores for all AS patients were 3.6 (5.25-2.29), 2.5 (4.22-0.91) and 3 (5-1), respectively. Serum procalcitonin levels were normal (< 0.05 ng/mL) for all patients and controls.

CONCLUSION

Serum procalcitonin levels were not high in AS patients and controls, and the levels were independent of disease activity and medications. If bacterial or fungal infection is suspected in an AS patient, serum procalcitonin level may be useful for diagnosis.

High serum levels of procalcitonin and soluble TREM-1 correlated with poor prognosis in pulmonary tuberculosis

OBJECTIVES

Comparisons of procalcitonin (PCT), C-reactive protein (CRP), and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) would expand our knowledge of which biomarker is the best predictor for outcomes of patients with pulmonary tuberculosis (PTB).

METHODS

We prospectively enrolled 243 PTB patients, in whom PCT, CRP, and sTREM-1 measurement were performed to evaluate their prognostic value for 6-month mortality.

RESULTS

Serum PCT, CRP, and sTREM-1 levels on diagnosis of PTB were significantly higher in nonsurvivors (2.22 ± 6.22 vs. 0.13 ± 0.31 ng/mL, P = 0.043; 42.1 ± 59.4 vs. 12.5 ± 29.1 mg/L, P = 0.004; 332 ± 362 vs. 128 ± 98 pg/mL, P = 0.001, respectively) as compared with 6-month survivors. In multivariate Cox regression analysis, PCT ≧ 0.5 ng/mL (hazard ratio 4.13, 95% CI, 1.99-8.58) and sTREM-1 ≧ 129 pg/mL (hazard ratio 3.39, 95% CI, 1.52-7.58) remained independent mortality predictors. Serum PCT and sTREM-1 levels above the cutoffs were also associated with the presence of disseminated tuberculosis.

CONCLUSIONS

Among PTB patients, higher PCT, CRP, and sTREM-1 levels are observed in nonsurvivors than in 6-month survivors. Serum levels of PCT and sTREM-1 over the cutoffs are independently associated with a poor outcome. In addition, higher PCT and sTREM-1 levels would raise the clinical suspicion of disseminated tuberculosis.

Novel biomarkers to detect infection in revision hip and knee arthroplasties

BACKGROUND

A periprosthetic joint infection is one of the most challenging complications associated with THA and TKA. In the diagnostic process for detecting a periprosthetic joint infection, one of the most important steps is analysis of laboratory infection biomarkers.

QUESTIONS/PURPOSES

We investigated the sensitivity and specificity of the biomarkers procalcitonin, interleukin 6 (IL-6), and interferon α (IFN-α) as compared with conventional biomarkers (C-reactive protein [CRP], leukocyte level) for a periprosthetic joint infection associated with revision arthroplasties.

METHODS

We prospectively included and analyzed 84 patients (124 revision arthroplasties). The blood parameters of interest were procalcitonin, IL-6, IFN-α, leukocyte level, and CRP. Samples were taken preoperatively and on the first, third, and seventh postoperative days. The sensitivity and specificity of these biomarkers then were calculated.

RESULTS

Considering the preoperative values of 84 patients (124 operations), procalcitonin, IL-6, CRP, and leukocyte level correlated with periprosthetic joint infection, whereas IFN-α did not. A procalcitonin cut-off level of 0.35 ng/mL revealed a sensitivity of 80% and specificity of 37%. An IL-6 cut-off level of 2.55 pg/mL had a sensitivity of 92% and specificity of 59%.

CONCLUSIONS

In this study procalcitonin and IL-6 were helpful for detecting periprosthetic joint infections in revision arthroplasties, although CRP generally was superior. Procalcitonin and IL-6 may be considered adjuvant tests when the diagnosis of a periprosthetic joint infection is in doubt. This study showed, in addition to conventional biomarkers such as CRP and leukocyte level, procalcitonin and IL-6 were helpful for detecting infections associated with revision arthroplasties.

Procalcitonin as a marker of bacteremia in children with fever and a central venous catheter presenting to the emergency department

OBJECTIVE

To evaluate the clinical use of procalcitonin (PCT) as a rapid marker for the identification of bacteremia in the emergency department (ED) population of children with fever and a central venous catheter (CVC).

METHODS

Children were identified on presentation to the ED with a chief complaint of fever and who had a CVC. Fever was defined as 38°C or higher orally. Patients were excluded from the study if they had received antibiotics within the previous 24 hours of presenting to the ED, if they had a peripherally inserted central catheter line or by parental refusal. On presentation to the ED, all patients had a complete blood cell count with differential, blood culture from the central line, and PCT levels drawn. All had empiric antibiotics initiated. Blood culture results were recorded, and in the case of positive cultures, time to positive culture was noted.

RESULTS

Sixty-two patients (aged 5 months-18 y) were enrolled, and 14 (23%) had a positive culture. Mean PCT value in bacteremic patients was 18.47 ± 31.6 ng/mL and 0.65 ± 1.2 ng/mL in nonbacteremic patients (P < 0.001). Median PCT for negative blood culture was 0.23 ng/mL (interquartile range, 0.11-0.61) and 1.15 ng/mL for a positive blood culture (interquartile range, 0.45-29.16). The receiver operating characteristic analysis identified a level of PCT of 0.3 ng/mL as the best cutoff point that produced a sensitivity of 93% and a specificity of 63% (area under the curve, 0.82).

CONCLUSIONS

The PCT levels are useful in identifying children with fever and a CVC who are bacteremic in the ED.

Comparing the accuracy of predictors of mortality in ventilator-associated pneumonia

OBJECTIVE

Levels of procalcitonin, midregional pro-atrial natriuretic peptide (MR-proANP), C-terminal provasopressin (copeptin), and C-reactive protein (CRP), as well as Sequential Organ Failure Assessment (SOFA) scores, are associated with severity and described as predictors of outcome in ventilator-associated pneumonia (VAP). This study sought to compare the predictive value of these biomarkers for mortality in VAP.

METHODS

An observational study of 71 patients with VAP. Levels of procalcitonin, MR-proANP, copeptin, and CRP, together with SOFA scores, were determined at VAP onset, designated day 0 (D0), and on day 4 of treatment (D4). Patients received empirical antimicrobial therapy, with modifications based on culture results. Patients who died before D28 were classified as nonsurvivors.

RESULTS

Of the 71 patients evaluated, 45 were classified as survivors. Of the 45 survivors, 35 (77.8%) received appropriate antimicrobial therapy, compared with 18 (69.2%) of the 26 nonsurvivors (p = 0.57). On D0 and D4, the levels of all biomarkers (except CRP), as well as SOFA scores, were lower in eventual survivors than in eventual nonsurvivors. For D0 and D4, the area under the ROC curve was largest for procalcitonin. On D0, MR-proANP had the highest positive likelihood ratio (2.71) and positive predictive value (0.60), but procalcitonin had the highest negative predictive value (0.87). On D4, procalcitonin had the highest positive likelihood ratio (3.46), the highest positive predictive value (0.66), and the highest negative predictive value (0.93).

CONCLUSIONS

The biomarkers procalcitonin, MR-proANP, and copeptin can predict mortality in VAP, as can the SOFA score. Procalcitonin alone has the greatest predictive power for such mortality.

Serum procalcitonin concentration in the evaluation of febrile infants 2 to 60 days of age

OBJECTIVE

Febrile infants younger than 60 days are at risk for serious bacterial infections (SBIs) and often undergo extensive laboratory investigation and hospitalization. We aim to determine the diagnostic value of serum procalcitonin (PCT) concentration for identification of febrile infants at low risk for SBI in comparison to the Rochester Criteria (RC).

METHODS

Infants 2 to 60 days of age with rectal temperature 38°C were enrolled between May 2004 and March 2007. Blood was obtained from each, and PCT was assessed using BRAHMS PCT LIA method. Information for identification of low-risk infants using RC was obtained. Negative predictive value, sensitivity, specificity, and likelihood ratio of PCT were compared with the RC. In univariate analysis, the components of RC and PCT were considered. Variables holding a significant association with the absence of SBI were included in a backward stepwise logistic regression model with SBI as the dependent variable, creating new low risk criteria.

RESULTS

One hundred fifty-five patients were enrolled. Thirteen (8.4%) had an SBI. Procalcitonin concentration at a cutoff value of 0.26 ng/mL is similar in sensitivity (92%) and better in specificity (64%) than RC. A combination of urine white blood cell and PCT was the best model in the regression analysis.

CONCLUSIONS

Procalcitonin concentration is a serological marker for identification of or exclusion of SBI in infants aged 2 to 60 days. The predictive value of PCT in combination with urinary white blood cell count may be clinically useful. A validation study is indicated.

Procalcitonin as a marker of bacterial infection in children undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Owing to systemic inflammatory response syndrome, the diagnosis of post-operative infection after cardiopulmonary bypass is difficult to assess in children with the usual clinical and biological tools. Procalcitonin could be informative in this context.

METHODS

Retrospective study in a paediatric intensive care unit. Blood samples were collected as soon as infection was clinically suspected and a second assay was performed 24 hours later. Using referenced criteria, children were retrospectively classified into two groups: infected and non-infected.

RESULTS

Out of the 95 children included, 14 were infected. Before the third post-operative day, procalcitonin median concentration was significantly higher in the infected group than in the non-infected group - 20.24 nanograms per millilitre with a 25th and 75th interquartile of 15.52-35.71 versus 0.72 nanograms per millilitre with a 25th and 75th interquartile of 0.28 to 5.44 (p = 0.008). The area under the receiver operating characteristic curve was 0.89 with 95% confidence intervals from 0.80 to 0.97. The best cut-off value to differentiate infected children from healthy children was 13 nanograms per millilitre with 100% sensitivity - 95% confidence intervals from 51 to 100 - and 85% specificity - 95% confidence intervals from 72 to 91. After the third post-operative day, procalcitonin was not significantly higher in infected children - 2 nanograms per millilitre with a 25th and 75th interquartile of 0.18 to 12.42 versus 0.37 nanograms per millilitre with a 25th and 75th interquartile of 0.24 to 1.32 (p = 0.26). The area under the receiver operating characteristic curve was 0.62 with 95% confidence intervals from 0.47 to 0.77. A procalcitonin value of 0.38 nanograms per millilitre provided a sensitivity of 70% with 95% confidence intervals from 39 to 89 for a specificity of 52% with 95% confidence intervals from 34 to 68. After the third post-operative day, a second assay at a 24-hour interval can improve the sensitivity of the test.

CONCLUSIONS

Procalcitonin seems to be a discriminating marker of bacterial infection during the post-operative days following cardiopulmonary bypass in children.

Serum procalcitonin in systemic autoimmune diseases--where are we now?

OBJECTIVES

To review the current evidence regarding the value of measuring procalcitonin (PCT) levels in patients with systemic autoimmune diseases, with a focus on the evidence for diagnostic and analytical performance of this biomarker. A brief description of the pathophysiological basis of this biomarker is also included.

METHODS

Using PubMed from the National Library of Medicine, relevant English literature on PCT in patients with different systemic autoimmune diseases, from 1990 to 2009, was reviewed. The search used keywords referring to procalcitonin and systemic lupus erythematosus, antineutrophil cytoplasmic antibody-associated systemic vasculitis, Goodpasture syndrome, rheumatoid arthritis, and giant cell arteritis.

RESULTS

When used in the appropriate clinical setting, the measurement of serum PCT levels is valuable as a marker of severe systemic bacterial and fungal infections and sepsis. Information regarding plasma PCT levels in patients with active underlying systemic autoimmune diseases is limited, primarily from observational studies and case series, with considerable variability of patient characteristics and clinical settings. In the detection of systemic infection concomitant with autoimmune diseases, PCT had a diagnostic sensitivity of 53 to 100% and a specificity of 84 to 97% (depending on the selection criteria) and was superior to other inflammatory markers tested. Most of the studies used a semiquantitative test for PCT measurement (functional assay sensitivity <0.5 ng/mL), which can explain the low sensitivity of the test. PCT levels were not significantly affected by renal function abnormalities or immunosuppressive agents. Although high PCT levels commonly occurred with infection, elevated levels of PCT could be found in patients with vasculitis without evidence of infection, often correlated with high disease activity scores.

CONCLUSIONS

Significantly elevated PCT levels offer good specificity and sensitivity for systemic infection in patients with systemic autoimmune diseases, regardless of the use of corticosteroids or immunosuppressive agents. PCT measurement may add to diagnostic accuracy in patients with systemic autoimmune diseases who present with a febrile illness, especially when highly sensitive PCT assays and specific PCT cutoff ranges are used in a predefined clinical setting (reflecting the likelihood of infection versus an autoimmune disease flare). However, there are limitations when using this biomarker in patients with systemic autoimmune diseases. PCT levels should not replace the necessary extensive diagnostic workup, which should include a thorough history and physical examination, combined with appropriate immunological, microbiological, radiological, and histological data.

Procalcitonin as an early marker of bacterial infection in neutropenic febrile children with acute lymphoblastic leukemia

OBJECTIVE AND DESIGN

The aim of this study was to assess the value of procalcitonin (PCT), C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-a), interleukin (IL)-1b, IL-8, and soluble TNF receptor II (sTNFRII) in early and rapid diagnosis of infection in neutropenic children with acute lymphoblastic leukemia (ALL) and to distinguish bacterial from viral infections.

PATIENTS

The study included five groups (A, B, C, D, and E) of children with ALL undergoing intensive chemotherapy. Groups A and B consisted of neutropenic children with bacterial and viral infection, respectively. Groups C and D consisted of nonneutropenic children with bacterial and viral infection, respectively. Group E consisted of children without neutropenia and without fever.

METHODS

In all groups, blood samples were collected upon admission and then for 7 days on a daily basis. Levels of CRP, PCT, TNF-a, IL-1b, IL-8, and sTNFRII were determined in all blood samples.

RESULTS

We found a highly significant difference in PCT levels between bacterial and nonbacterial episodes. Sensitivity and specificity of PCT were 94 and 96.5%, respectively.

CONCLUSIONS

Serial measurement of PCT levels on a daily basis seems to be helpful for early prediction of severe bacterial infections, monitoring febrile episodes regarding response to antibiotic therapy, and early detection of complications in the infectious process.

The Role of Procalcitonin in Gynaecological Surgery

We evaluated postoperative concentrations of inflammatory indicators, including procalcitonin, after gynaecological operations for benign and malignant tumours in patients with a normal postoperative course and assessed the utility of procalcitonin in differentiating between non-bacterial inflammation and bacteraemic complications in the postoperative period. This prospective study included 99 patients: 47 after a standard gynaecological operation (Piver I) and no postoperative infectious complications (group 1), 35 after a major procedure (Piver II or III) and no postoperative infectious complications (group 2), and five with postoperative sepsis after Piver II or III procedures (group 3). We also studied serum procalcitonin concentrations in a group of 12 patients (group 4) with terminal forms of gynaecological cancer who were hospitalized for palliative treatment but did not undergo surgery. Postoperative C-reactive protein (CRP) concentration corresponded with extent of tissue trauma in groups 1 and 2 and was significantly lower in group 1 than group 2. Inflammatory indicators were highest in groups 1 and 2 on postoperative day 2. In group 3, in which sepsis developed, values were highest on postoperative day 4. In particular, procalcitonin was > 2 ng/ml in all patients with postoperative sepsis by postoperative day 2 but was always ≤ 2 ng/ml in patients without sepsis. In contrast, high procalcitonin levels were noted in the patients in group 4 compared with group 3, with two-thirds of group 4 patients having levels > 2 ng/ml, with no signs of infection or raised CRP. It is concluded that, for early detection of postoperative infectious complications after gynaecological surgery, procalcitonin levels > 2 ng/ml are more specific than CRP.

Procalcitonin for differential diagnosis of graft rejection and infection in patients with heart and/or lung grafts

OBJECTIVES

Investigation of the reliability of Procalcitonin (PCT) for differential diagnosis of acute rejections and non-viral infections in heart and lung transplanted patients.

DESIGN

Retrospective study.

SETTING

Transplant intensive care unit (ICU) at a university hospital.

PATIENTS

57 heart, 18 lung and 3 heart-lung transplant patients.

MEASUREMENTS

PCT was measured in plasma samples of heart and lung transplanted patients using a commercial immuno-luminescence assay and was compared with values of C-reactive protein (CRP) and leukocytes (WBC).

RESULTS

PCT was elevated in patients suffering from bacterial and fungal infections. The magnitude of values was clearly associated with the severity of the infection. Rejections and viral infections did not interfere with the PCT release.

CONCLUSION

PCT is a reliable predictor with discriminating power for non-viral systemic infections in patients after heart and/or lung transplantation. PCT allows an early differential diagnosis between rejection (AR) and bacterial/fungal infection (IF) and thus a rapid and focused therapeutic intervention. It avoids unnecessary antibiotic treatment which could be toxic for the graft itself in patients with rejection only. PCT provides vital information early to clinicians and allows them to improve the management of bacterial/fungal infections in immunocompromized transplant patients. PCT thus facilitates and improves the outcome of survival rate and the quality of life in the postoperative period of patients with heart and/or lung grafts.

Procalcitonin for differential diagnosis of graft rejection and infection in patients with heart and/or lung grafts

OBJECTIVES

Investigation of the reliability of Procalcitonin (PCT) for differential diagnosis of acute rejections and non-viral infections in heart and lung transplanted patients.

DESIGN

Retrospective study.

SETTING

Transplant intensive care unit (ICU) at a university hospital.

PATIENTS

57 heart, 18 lung and 3 heart-lung transplant patients.

MEASUREMENTS

PCT was measured in plasma samples of heart and lung transplanted patients using a commercial immuno-luminescence assay and was compared with values of C-reactive protein (CRP) and leukocytes (WBC).

RESULTS

PCT was elevated in patients suffering from bacterial and fungal infections. The magnitude of values was clearly associated with the severity of the infection. Rejections and viral infections did not interfere with the PCT release.

CONCLUSION

PCT is a reliable predictor with discriminating power for non-viral systemic infections in patients after heart and/or lung transplantation. PCT allows an early differential diagnosis between rejection (AR) and bacterial/fungal infection (IF) and thus a rapid and focused therapeutic intervention. It avoids unnecessary antibiotic treatment which could be toxic for the graft itself in patients with rejection only. PCT provides vital information early to clinicians and allows them to improve the management of bacterial/fungal infections in immunocompromized transplant patients. PCT thus facilitates and improves the outcome of survival rate and the quality of life in the postoperative period of patients with heart and/or lung grafts.

Procalcitonin in young febrile infants for the detection of serious bacterial infections

OBJECTIVES

The objectives of the study were (1) to study the test performance of procalcitonin for identifying serious bacterial infections in febrile infants <or=90 days of age without an identifiable bacterial source and (2) to determine an optimal cutoff value to identify infants at low risk for serious bacterial infections.

METHODS

A prospective observational study was performed with febrile infants <or=90 days of age presenting to an urban, pediatric, emergency department. Serum procalcitonin levels were measured by using an automated high-sensitivity assay. An optimal procalcitonin cutoff value was selected to maximize sensitivity and negative predictive value for the detection of serious bacterial infections. Infants were classified as having definite, possible, or no serious bacterial infections.

RESULTS

A total of 234 infants (median age: 51 days) were studied. Thirty infants (12.8%) had definite serious bacterial infections (bacteremia: n = 4; bacteremia with urinary tract infections: n = 2; urinary tract infections: n = 24), and 12 infants (5.1%) had possible serious bacterial infections (pneumonia: n = 5; urinary tract infections: n = 7). Mean procalcitonin levels for definite serious bacterial infections (2.21 +/- 3.9 ng/mL) and definite plus possible serious bacterial infections (2.48 +/- 4.6 ng/mL) were significantly higher than that for no serious bacterial infection (0.38 +/- 1.0 ng/mL). The area under the receiver operating characteristic curve was 0.82 for definite serious bacterial infections and 0.76 for definite and possible serious bacterial infections. For identifying definite and possible serious bacterial infections, a cutoff value of 0.12 ng/mL had sensitivity of 95.2%, specificity of 25.5%, negative predictive value of 96.1%, and negative likelihood ratio of 0.19; all cases of bacteremia were identified accurately with this cutoff value.

CONCLUSIONS

Procalcitonin has favorable test characteristics for detecting serious bacterial infections in young febrile infants. Procalcitonin measurements performed especially well in detecting the most serious occult infections.

Maternal venous procalcitonin levels do not correlate with umbilical cord blood and venous blood concentrations in the neonate

BACKGROUND

To compare procalcitonin (PCT) concentrations between maternal blood and levels in umbilical cord or venous blood of neonates who were born with or without infection.

METHODS

Forty-six women with singleton pregnancies, complicated by premature rupture of membranes, preterm delivery and/or chorioamnionitis, were enrolled in this study. The study group comprised 15 patients and their infected newborns. The control group consisted of 31 women and their healthy newborns. We compared PCT concentrations between maternal, umbilical cord and neonatal serum, in both study and control groups. Additionally, PCT levels were compared between the corresponding compartments.

RESULTS

PCT concentrations in the umbilical cord and venous blood in infected newborns, but not in non-infected neonates, were significantly higher than maternal serum PCT levels. PCT concentrations of mothers who delivered infected newborns were comparable to those in the controls. However, PCT concentrations in the umbilical cord and in the venous blood of the infected newborns were higher than in healthy newborns.

CONCLUSION

Measurement of maternal PCT concentration during labor does not contribute to early prediction of infection in the neonate. However, umbilical cord PCT concentrations, as well as its neonatal venous levels on the second day of life, seem to be related to intrauterine infection, and may be a useful tool in the diagnosis of early neonatal infection.

Procalcitonin as a screening test for late-onset sepsis in preterm very low birth weight infants

OBJECTIVE

To compare the utility of procalcitonin (PCT) vs C-reactive protein (CRP) as indicators of late-onset neonatal sepsis in very low birth weight (VLBW) infants.

METHODS

PCT and CRP levels were measured in VLBW infants with suspected sepsis and controls. Comparisons were made between infected vs noninfected infants. Using cutoff values of 0.5 and 1.0 ng/ml for PCT and 0.8 mg/dl for CRP, sensitivity, specificity, positive and negative predictive values were calculated to evaluate these assays as potential predictors of late-onset sepsis.

RESULTS

A total of 67 infants were evaluated. Mean PCT levels were significantly higher in the infected group (5.41 ng/ml) compared to the noninfected group (0.43 ng/ml) (p < 0.001). At a cut off value of 0.5 ng/ml, the sensitivity of PCT was 97%, whereas that of CRP was 73% in predicting late-onset sepsis. At a PCT cutoff of 1.0 ng/ml, sensitivities of PCT and CRP were similar (72% each).

CONCLUSION

PCT (0.5 ng/ml) is more sensitive than CRP in predicting late-onset sepsis in VLBW infants.

Serum procalcitonin and cerebrospinal fluid cytokines level in children with meningitis

AIMS: To determine the level of serum procalcitonin and cerebrospinal fluid cytokines in children with bacterial or viral meningitis and to document the use of these parameters in differential diagnosis. RESULTS: Before the start of antibiotic treatment, serum procalcitonin and tumor necrosis factor alpha levels were found to be higher in acute bacterial meningitis compared with viral meningitis and with the control group. Similarly, cerebrospinal fluid interleukin-6 levels were found to be significantly higher in children with acute bacterial meningitis compared with viral meningitis. However, no significant difference was determined between groups in respect to the cerebrospinal fluid interleukin-8 level. CONCLUSION: Serum procalcitonin and cerebrospinal fluid tumor necrosis factor alpha levels can be used in the early diagnosis of bacterial meningitis. Similarly, they may be useful adjuncts in differential diagnosis of bacterial and viral meningitis.

Procalcitonin as an early marker of infection in neonates and children

A child or neonate presenting with fever is a common medical problem. To differentiate between those with a severe bacterial infection and those with a localised bacterial or a viral infection can be a challenge. This review provides an overview of neonatal and paediatric studies that assess the use of procalcitonin as an early marker of bacterial infection. Procalcitonin is an excellent marker for severe, invasive bacterial infection in children. However, the use of procalcitonin in the diagnosis of neonatal bacterial infection is complicated, but if correctly used procalcitonin results in a higher specificity than C-reactive protein. In addition, procalcitonin has been shown to correlate with severity of disease (urinary tract infections and sepsis), and can therefore be used as a prognostic marker. Procalcitonin is therefore a useful additional tool for the diagnosis of bacterial disease in neonates and children.

Serum procalcitonin concentration in patients with Kawasaki disease

BACKGROUND

Procalcitonin (PCT) is a new parameter of inflammation, the clinical usefulness of which is currently being evaluated.

MATERIALS AND METHODS

We determined simultaneously the serum concentrations of PCT and C-reactive protein (CRP) as well as the white blood cell (WBC) count in 25 patients with Kawasaki disease (KD), 17 with bacterial infections, 10 with systemic autoimmune diseases, 17 with viral infections and 18 healthy children. The optimal cut-off value of each parameter for predicting coronary aneurysms was determined using receiver operating characteristic curves.

RESULTS

Significantly higher serum concentrations of PCT were observed in patients with KD (2.3 +/- 3.0 ng/ml) and bacterial infections (2.2 +/- 2.9 ng/ml) than in patients with autoimmune diseases (0.4 +/- 0.4 ng/ml) or viral infections (0.4 +/- 0.3 ng/ml), or in healthy children (0.2 +/- 0.1 ng/ml). The serum PCT but not the WBC count or CRP, differentiated the KD patients from the patients with autoimmune diseases. The optimal cut-off value of 3.0 ng/ml of PCT increased the prediction rate of coronary aneurysms that subsequently occurred in 4 (16%) patients with KD.

CONCLUSIONS

The serum PCT may be clinically useful for determining the severity of KD and for narrowing the differential diagnosis of patients with inflammatory diseases.

Elevation of procalcitonin level in patients with pulmonary tuberculosis and in medical staff with close patient contact

BACKGROUND

Several studies have shown that serum procalcitonin levels increase conspicuously in acute and systemic inflammatory diseases. However, there is insufficient information concerning its activity in chronic infectious diseases such as tuberculosis. In this study, we aimed to assess serum level of procalcitonin in patients with active pulmonary tuberculosis and in medical staff at high risk due to close patient contact (high-risk staff).

METHODS

For this purpose, 30 patients (6 female, 24 male) and 20 staff (8 female, 12 male) were evaluated. Twenty eight healthy blood donors (9 female, 19 male) made up the control group.

RESULTS

Serum procalcitonin level in patients with tuberculosis was 0.76 +/- 0.20 ng/mL. Procalcitonin levels in active tuberculosis patients and staff were not significantly different (p=0.381); however, differences between active tuberculosis patients and control group were significant (p<0.001). In addition, serum procalcitonin levels were also different in staff and control groups (p<0.001).

CONCLUSIONS

This study showed that procalcitonin levels increased both in patients with pulmonary tuberculosis and in the staff. This result considered that procalcitonin could be a good indicator of inflammation in patients with chronic diseases and in persons exposed to long-lasting infections.

C-reactive protein, interleukin-6, and procalcitonin in the immediate postnatal period: influence of illness severity, risk status, antenatal and perinatal complications, and infection

BACKGROUND

Studies of the diagnostic accuracy of most laboratory tests for early-onset neonatal sepsis have yielded variable results. We investigated whether some of this variation might be attributable to differences in population baseline severity and risk status as well as to specific ante- and perinatal variables, independent of the presence of neonatal infection.

METHODS

The Score for Neonatal Acute Physiology (SNAP) was used to define illness severity, with SNAP Perinatal Extension (SNAP-PE) used to define the combined physiologic and perinatal mortality risk. A total of 134 ill newborns (19 with early-onset infection and 115 with no infection) were available for simultaneous analysis of the association of SNAP, SNAP-PE, and maternal and perinatal variables with C-reactive protein (CRP), interleukin-6 (IL-6), and procalcitonin (PCT) concentrations at birth and at 24 and 48 h of life.

RESULTS

Early-onset neonatal infection was associated with significant increases in CRP, IL-6, and PCT concentrations at all three time points, independent of illness severity. However, among babies without infection, higher SNAP and SNAP-PE scores were associated with higher IL-6 concentrations at birth. Certain maternal or perinatal variables altered IL-6 and PCT values in the infected as well as in the uninfected neonates. However, if different cutoff points were used at any of the three neonatal ages, PCT sensitivity and specificity were greater than those of CRP or IL-6.

CONCLUSIONS

Illness severity and risk status are unlikely to interfere with the use of CRP and PCT for detection of early-onset neonatal sepsis. In contrast, the diagnostic value of IL-6 at birth may be altered by physiologic severity and risk indexes. The reliability of CRP, IL-6, and PCT for the diagnosis of early-onset neonatal infection requires specific cutoff values for each evaluation time point over the first 48 h of life.

Procalcitonin and other markers of infection. What should be their role in clinical practice?

Clinicians are always faced with a decision when confronted with a febrile patient; they must decide between what is an infectious condition and what is not, and between what merits hospital observation, what requires empirical antibiotic treatment and what needs outpatient follow-up. In this respect, judgement based on medical history and physical examination outweigh the predictive value of various laboratory markers of infection, as the latter generally reflect a nonspecific reaction of the host to widely different infectious and inflammatory stimuli. In the evaluation of specific subgroups of patients, e.g. those in the intensive care unit, laboratory tests should also preferably form a continuum with medical history and physical examination, aimed at clarifying host condition, the setting and the source of a possible infection.

Postnatal increase of procalcitonin in premature newborns is enhanced by chorioamnionitis and neonatal sepsis

BACKGROUND

To determine the influence of chorioamnionitis and neonatal sepsis on procalcitonin (PCT) levels in very-low-birth-weight (VLBW) infants within the first week of life.

DESIGN

PCT serum levels were measured in cord blood 1 h after delivery and on day 3 and day 7 of life. Chorioamnionitis and neonatal sepsis within the first week were monitored.

RESULTS

Chorioamnionitis was present in eight of 37 patients (21.6%). PCT on day 3 was increased in both the "No chorioamnionitis" (2.54 ng mL(-1), SEM 0.51) and "Chorioamnionitis" (6.96 ng mL(-1), SEM 2.93) groups of VLBW infants compared with the 1st hour values (0.45 and 0.58 ng mL(-1) SEM 0.07 and 0.11, respectively, P < 0.001) of the same patients. The postnatal gain was higher in the "Chorioamnionitis" group (P < 0.01). Neonatal sepsis was diagnosed (after exclusion) in 12 of 32 patients (37.5%). Mean values of maximum PCT in patients with and without sepsis were 8.41 ng mL(-1) (SEM 1.87) and 3.02 ng mL(-1) (SEM 1.38), respectively (P < 0.05). Sensitivity to sepsis of PCT, ratio of immature to total neutrophils (I : T), and C-reactive protein (CRP) were 75%, 50% and 25%, respectively.

CONCLUSIONS

In the group of VLBW infants the PCT level within 72 h of delivery was markedly increased in patients with chorioamnionitis. Compared with I : T and CRP, PCT appears to be a more sensitive marker of neonatal sepsis.

Hypocalcemic syndromes

Hypocalcemia is common in the ICU and is a marker of poor prognosis. The mechanisms behind the low calcium levels include extravasation, increased chelation, intracellular overload of calcium, and an altered parathyroid hormone (PTH) secretion. Hypocalcemia and an altered PTH secretion seem to be related to systemic inflammation, but it is not known today if this response is appropriate or not. Therefore, a general supplementation with calcium in these patients cannot be recommended at this stage.

Procalcitonin release patterns in a baboon model of trauma and sepsis: relationship to cytokines and neopterin

OBJECTIVES

Procalcitonin (PCT) has been described as an early, discriminating marker of bacteria-associated sepsis in patients. However, little is known of its source and actions, in part because no appropriate animal models have been available. We tested the hypothesis that plasma PCT increases during various pathophysiological conditions, such as hemorrhagic shock and sepsis, which differ with regard to the degree of associated endotoxemia. We further hypothesized that in sepsis, PCT would be significantly different in survivors vs. nonsurvivors.

DESIGN

Prospective, blinded analysis of previously collected plasma of experimental animals.

SETTING

Independent nonprofit research laboratory in a trauma hospital and a contract research institute.

SUBJECTS

A total of 22 male baboons (17.5-31 kg).

INTERVENTIONS

Hemorrhagic-traumatic shock was induced by hemorrhage for up to 3 hrs, reperfusion with shed blood and infusion of cobra venom factor (n = 7). By using a similar experimental setup, severe hyperdynamic sepsis was induced (n = 15) by intravenous infusion of live Escherichia coli (2 x 10(9) colony-forming units/kg) over 2 hrs, followed by antibiotic therapy (gentamicin 4 mg/kg twice a day).

MEASUREMENTS AND MAIN RESULTS

Plasma PCT at baseline was barely detectable, but levels increased significantly (p < .05) to 2+/-1.8 pg/mL 2 hrs after the start of reperfusion in the shock group, and to 987+/-230 pg/mL at 4 hrs after E. coli in the sepsis group. Levels were maximal between 6 and 32 hrs and had returned nearly to baseline levels at 72 hrs. Interleukin-6 levels paralleled the course of PCT measurements, whereas a significant increase in neopterin was seen at 24 hrs. PCT levels were approximately three times higher in the sepsis group than in the shock group, corresponding to endotoxin levels (at the end of hemorrhage, 286+/-144 pg/mL vs. 3576+/-979 pg/mL at the end of E. coli infusion; p = .003). PCT levels were significantly different at 24 hrs between survivors (2360+/-620 pg/mL) and nonsurvivors (4776+/-563 pg/mL) in the sepsis group (p = .032), as were interleukin-6 (1562+/-267 vs. 4903+/-608 pg/mL; p = .01) and neopterin/creatinine ratio (0.400+/-0.038 vs. 0.508+/-0.037; p = .032).

CONCLUSIONS

PCT is detectable in the baboon as in humans, both in hemorrhagic shock and sepsis. PCT levels are significantly higher in sepsis than in hemorrhage, a finding that is probably related to the differences in endotoxin. The baboon can be used for the study of PCT kinetics in both models; PCT kinetics are clearly different from other markers of sepsis, either IL-6 or neopterin, in both models. There are significant differences between survivors and nonsurvivors in the sepsis model.