Additional benefit of procalcitonin to C-reactive protein to assess disease activity and severity in Crohn's disease

Procalcitonin in inflammatory bowel disease: A diagnostic or prognostic marker

Serological biomarkers have been rapidly progressing as non-invasive tests for the early detection of inflammatory bowel disease (IBD). Procalcitonin (PCT) is a novel acute-phase reactant protein that is elevated in the inflammatory process, especially in bacterial infections. This study aimed to review the diagnostic value of PCT in IBD activity. However, there were controversies about the role of PCT in the detecting of IBD disease activity. Studies showed varied diagnostic cut-points (ranging from 0.13 to 1.0 ng/dl) and sensitivity up to 93 %. Although the clear role of PCT as a valuable diagnostic marker was not identified in determining disease activity, PCT measurement in addition to other inflammatory markers can improve the diagnostic value of these markers. Moreover, further studies are required to confirm PCT's value in distinguishing IBD disease activity.

Review article: how the intestinal microbiota may reflect disease activity and influence therapeutic outcome in inflammatory bowel disease

BACKGROUND

Intestinal bacteria produce metabolites and by-products necessary for homeostasis. Imbalance in this equilibrium is linked to multiple pathologies including inflammatory bowel disease (IBD). The role of the gut microbiota in determining treatment response is becoming apparent, and may act as biomarker for efficacy.

AIM

To describe knowledge about the intestinal microbiota on disease severity and treatment outcomes in IBD METHODS: Descriptive review using PubMed to identify literature on the intestinal microbiota in IBD RESULTS: Severe IBD has a less diverse microbiota with fewer commensal microbiota communities and more opportunistic pathogenic bacteria originating from the oral cavity or respiratory tract. IBD treatments can alter gut microbiota composition, but in vitro/in vivo studies are needed to prove causation. A diversification of the microbiota is observed during remission. Patients with a more diverse baseline microbiome and higher microbial diversity show better response to anti-tumour necrosis factor-α, vedolizumab and ustekinumab therapy. Higher abundance of short chain fatty acid-producing bacteria, fewer mucus-colonising bacteria and lower abundance of pro-inflammatory bacteria have also been associated with a favourable outcome. Predictive models, based on a combination of microbiota, clinical data and serological markers, have good accuracy for treatment outcome and disease severity.

CONCLUSION

The intestinal microbiota in IBD carries a set of promising biomarkers of disease activity and prediction of therapeutic outcome. Current insights may also help in designing microbiota modulation strategies to improve outcomes in IBD.

Biochemical Biomarkers of Mucosal Healing for Inflammatory Bowel Disease in Adults

Mucosal healing (MH) is the key therapeutic target of inflammatory bowel disease (IBD). The evaluation of MH remains challenging, with endoscopy being the golden standard. We performed a comprehensive overview of the performance of fecal-, serum-, and urine-based biochemical markers in colonic IBD to find out whether we are ready to replace endoscopy with a non-invasive but equally accurate instrument. A Pubmed, Web of Knowledge, and Scopus search of original articles as potential MH markers in adults, published between January 2009 and March 2020, was conducted. Finally, 84 eligible studies were identified. The most frequently studied fecal marker was calprotectin (44 studies), with areas under the curves (AUCs) ranging from 0.70 to 0.99 in ulcerative colitis (UC) and from 0.70 to 0.94 in Crohn`s disease (CD), followed by lactoferrin (4 studies), matrix metalloproteinase-9 (3 studies), and lipocalin-2 (3 studies). The most frequently studied serum marker was C-reactive protein (30 studies), with AUCs ranging from 0.60 to 0.96 in UC and from 0.64 to 0.93 in CD. Fecal calprotectin is an accurate MH marker in IBD in adults; however, it cannot replace endoscopy and the application of calprotectin is hampered by the lack of standardization concerning the cut-off value. Other markers are either not sufficiently accurate or have not been studied extensively enough.

Serum Procalcitonin as a Potential Early Predictor of Short-Term Outcomes in Acute Severe Ulcerative Colitis

BACKGROUND

Delayed colectomy can be life-threatening for patients with acute severe ulcerative colitis (ASUC). However, few biomarkers can predict the outcomes of ASUC patients before treatment. Serum procalcitonin (PCT) has been observed to be increased in ASUC patients.

AIM

The aim of this study was to estimate the association between serum PCT and short-term outcomes in patients with ASUC.

METHODS

A single-center observational study was conducted at a referral hospital from January 2012 to January 2018. Hospitalized ASUC patients, who were administered intravenous corticosteroids (IVCS), were enrolled and followed up for 6 months. The primary outcome was IVCS failure; the secondary outcome was colectomy. Relationships between indicators and clinical outcomes were assessed.

RESULTS

Of 152 ASUC patients enrolled in this study, 81 responded to IVCS and 71 failed (62 required short-term colectomy and 9 responded to second-line rescue therapy). Serum PCT on admission was significantly higher in IVCS-failure cases and surgical cases than in medical responders. Serum PCT ≥ 0.10 µg/L (OR = 4.134, p = 0.001) predicted IVCS failure with specificity of 0.741, and the combined measurement with fecal calprotectin (FC) ≥ 1500 µg/g improved the sensitivity. Serum PCT correlated significantly with the Ulcerative Colitis Endoscopic Index of Severity (r = 0.416, p < 0.001) and FC (r = 0.384, p < 0.001).

CONCLUSION

Serum PCT on admission could be a potential early non-invasive predictive biomarker for IVCS failure in ASUC patients, and a combination of PCT and FC could improve the predictive value.

Usefulness of Procalcitonin in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Background

Mixed results are reported for procalcitonin (PCT) as biomarkers of infection and disease activity in inflammatory bowel disease (IBD).

Method

We systematically evaluated and performed a meta-analysis on the usefulness of PCT in assessing infection and disease activity in IBD.

Results

The pooled standardized mean difference of PCT for those with infection compared with those without was 1.59 (95% CI, 0.72–2.46, P &lt; 0.01) and those with active disease compared with those without was 1.22 (95% CI, 0.66–1.78, P &lt; 0.01), respectively.

Conclusion

PCT may potentially be useful in differentiating an infectious process from IBD and active from inactive IBD.

Use of biomarkers in inflammatory bowel disease

There are many useful biomarkers for initial diagnosis and the management of inflammatory bowel disease. Serologic biomarkers have been traditionally used because they are widely disposable, but recently faecal biomarkers, especially faecal calprotectin, have acquired great importance as they have shown to be more precise when establishing suspicion of the disease and also as predictors of mucosal healing or persistence of inflammatory activity. Faecal calprotectin is a good tool for predicting abnormal endoscopic studies, but has limited specificity because its levels can be altered in many digestive diseases presenting with similar symptoms. The precision of faecal calprotectin is higher when associated with other altered parameters, especially with C-reactive protein, or with clinical scores of inflammatory activity. Finally, there are many new generation serologic and faecal biomarkers. Despite there not being much evidence about these yet, some of them have shown promising results in different studies.

Sepsis Markers Soluble IL-2 Receptor and Soluble CD14 Subtype as Potential Biomarkers for Complete Mucosal Healing in Patients With Inflammatory Bowel Disease

BACKGROUND AND AIMS

Novel noninvasive biomarkers with high diagnostic accuracy are required to assess mucosal healing, which is associated with sustained clinical remission, in inflammatory bowel disease. This study aimed to explore sepsis markers as potential biomarkers for mucosal healing.

METHODS

Patients with ulcerative colitis [UC] or Crohn's disease [CD], who underwent blood tests for C-reactive protein [CRP], serum procalcitonin [PCT], soluble interleukin-2 receptor [sIL-2R], and plasma soluble CD14 subtype [sCD14-ST] within 2 weeks of endoscopy, were retrospectively recruited; and we assessed the relationship between marker levels and clinical features. Complete mucosal healing [cMH] was defined as a Mayo endoscopic subscore [MES] of 0 for UC and a simple endoscopic score for Crohn's disease [SES-CD] of 0 for CD.

RESULTS

In all, 68 UC patients and 33 CD patients were included in this study. In patients with UC, the sIL-2R level was significantly higher in patients without cMH than in those with cMH. The sIL-2R level had the highest diagnostic value for identifying cMH in UC. In patients with CD, CRP and sCD14-ST levels were significantly higher in patients without cMH than in those with cMH, and both CRP and sCD14-ST had good diagnostic values for identifying cMH. The sCD14-ST level had a high diagnostic value for identifying cMH even among CD patients with complete clinical remission, defined as a Harvey-Bradshaw index of 0.

CONCLUSIONS

The sIL-2R and sCD14-ST levels in patients with UC and CD, respectively, can be useful surrogate markers for identifying mucosal healing in inflammatory bowel disease.

Procalcitonin in inflammatory bowel disease: Drawbacks and opportunities

The measurement of procalcitonin has recently become a mainstay for the diagnosis and therapeutic management of severe bacterial infections, especially those sustained by Gram-negative bacteria. Therefore, the aim of this article is to provide a narrative overview on the potential role of procalcitonin measurement in patients with inflammatory bowel disease (IBD). According to the available scientific literature, the clinical significance of procalcitonin for diagnosing IBD or monitoring disease activity remains elusive, and its association with disease severity is confined to a limited number of case-control studies, with low sample size. Nevertheless, literature data also suggests that a supranormal procalcitonin serum concentration (i.e., > 0.5 ng/mL) may reflect the presence of a number of infective complications in IBD, especially bacterial enterocolitis, bacterial gastroenteritis, intraabdominal abscess, postsurgical infection and sepsis. Rather than for diagnosing or assessing disease activity, the measurement of this biomarker may hence retain practical clinical significance for early prediction, timely diagnosis and therapeutic monitoring of many IBD-associated infections and complications.

Efficacy of noninvasive evaluations in monitoring inflammatory bowel disease activity: A prospective study in China

AIM

To optimize the efficacy of noninvasive evaluations in monitoring the endoscopic activity of inflammatory bowel disease (IBD).

METHODS

Fecal calprotectin (FC), clinical activity index (CDAI or CAI), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and procalcitonin (PCT) were measured for 136 IBD patients. Also, FC was measured in 25 irritable bowel syndrome (IBS) patients that served as controls. Then, endoscopic activity was determined by other two endoscopists for colonic or ileo-colonic Crohn’s disease (CICD) with the “simple endoscopic score for Crohn’s disease” (SES-CD), CD-related surgery patients with the Rutgeerts score, and ulcerative colitis (UC) with the Mayo score. The efficacies of these evaluations to predict the endoscopic disease activity were assessed by Mann-Whitney test, χ² test, Spearman’s correlation, and multiple linear regression analysis.

RESULTS

The median FC levels in CD, UC, and IBS patients were 449.6 (IQR, 137.9-1344.8), 497.9 (IQR, 131.7-118.0), and 9.9 (IQR, 049.7) μg/g, respectively (P < 0.001). For FC, CDAI or CAI, CRP, and ESR differed significantly between endoscopic active and remission in CICD and UC patients, but not in CD-related surgery patients. The SES-CD correlated closely with levels of FC (r = 0.802), followed by CDAI (r = 0.734), CRP (r = 0.658), and ESR (r = 0.557). The Mayo score also correlated significantly with FC (r = 0.837), CAI (r = 0.776), ESR (r = 0.644), and CRP (r = 0.634). For FC, a cut-off value of 250 μg/g indicated endoscopic active inflammation with accuracies of 87.5%, 60%, and 91.1%, respectively, for CICD, CD-related surgery, and UC patients. Moreover, clinical FC activity (CFA) calculated as 0.8 × FC + 4.6 × CDAI showed higher area under the curve (AUC) of 0.962 for CICD and CFA calculated as 0.2 × FC + 50 × CAI showed higher AUC (0.980) for UC patients than the FC. Also, the diagnostic accuracy of FC in identifying patients with mucosal inflammation in clinical remission was reflected by an AUC of 0.91 for CICD and 0.96 for UC patients.

CONCLUSION

FC is the most promising noninvasive evaluation for monitoring the endoscopic activity of CICD and UC. CFA might be more accurate for IBD activity evaluation.

Differentiating Clostridium difficile Colitis from Clostridium difficile Colonization in Ulcerative Colitis: A Role for Procalcitonin

BACKGROUND/AIMS

Clostridium difficile infection (CDI) frequently complicates ulcerative colitis (UC) and can mimic disease flare. Differentiating UC flare from CDI remains a clinical challenge, particularly due to C. difficile colonization. Procalcitonin (PCT) is a serum biomarker for bacterial infections. We hypothesized that PCT would differentiate acute CDI from UC flare and C. difficile colonization.

METHODS

A single-center prospective cohort study was conducted from 2013 to 2016. All UC patients with a stool sample for C. difficile testing were eligible. A total of 117 patients were enrolled, while 20 were excluded. Chart review was performed.

RESULTS

Among 27 patients with CDI, median PCT was 60.7 (range 26-560.6) pg/mL, while among 90 patients without CDI, median PCT was 56.7 (range 25.1-2,252) pg/mL (p = 0.9). It was found that 14 patients with CDI responded completely to C. difficile treatment (CDI-R), while 8 patients did not and were diagnosed with UC flare (CDI-NR). For CDI-R, median PCT was 104.5 (range 26.3-560.6), compared to 40.3 (range 26.0-116.3) for CDI-NR (p = 0.036).

CONCLUSIONS

In UC patients presenting with diarrhea, serum PCT was not significantly higher in UC patients with positive C. difficile testing. However, PCT was significantly elevated in CDI-R versus CDI-NR, suggesting that PCT may have utility in making this discrimination.

Usefulness of Measuring Serum Procalcitonin Levels in Patients with Inflammatory Bowel Disease

BACKGROUND/AIMS

The relationships between serum procalcitonin, inflammatory bowel disease (IBD) and intestinal Behçet's disease (BD) have not been completely determined. We aimed to evaluate the usefulness of measuring serum procalcitonin levels to assess disease activity and infection stage in patients with IBD and intestinal BD.

METHODS

We retrospectively analyzed clinical data from 129 patients with IBD and intestinal BD for whom serum procalcitonin and C-reactive protein (CRP) levels were measured between January 2006 and February 2013.

RESULTS

The median serum procalcitonin levels in the IBD and intestinal BD with septic shock or sepsis (n=8), with localized infection (n=76), and without infection (n=45) were 3.46 ng/mL (range, 0.17 to 63.66 ng/mL), 0.22 ng/mL (range, 0.05 to 140.18 ng/mL), and 0.07 ng/mL (range, 0.00 to 31.50 ng/mL), respectively (p=0.001). The serum CRP levels in the IBD and intestinal BD patients did not differ according to the infection stage. Variations in serum procalcitonin levels were not observed in the IBD and intestinal BD patients with different disease activities.

CONCLUSIONS

Serum procalcitonin levels may not be affected by IBD and intestinal BD activity itself, although they may be affected by concomitant infection. Serum procalcitonin measurements could be more useful than CRP in determining the infection stage that reflects the severity of infection in IBD and intestinal BD patients.

Role of biomarkers in diagnosis and evaluation of disease activity of Crohn's disease

Crohn's disease (CD) is a group of chronic, relapsing inflammatory gastrointestinal diseases with unknown etiology. The goals of treatment are to induce the transition from active stage into inactive stage and to maintain remission. Therefore, it is important to diagnose and assess disease activity in patients with CD. Recently, noninvasive markers for intestinal inflammation have been wildly adopted in clinical practice in order to differentiate CD from other diseases, to grade inflammation, to assess the response to therapy, and to demonstrate recurrent inflammation after medical or surgically-induced remission. Fecal and serum calprotectins are among the best-studied noninvasive biomarkers of inflammation in CD which have attracted clinicians' attention. This paper gives an overview of the clinical implications of biomarkers for diagnosing and monitoring disease activity of CD.

Procalcitonin in Crohn's disease with fever episodes, a variable to differentiate intra-abdominal abscess from disease flares

BACKGROUND

Crohn's Disease (CD) is a chronic inflammatory disease accompanied by many complications, such as intra-abdominal abscess (IAA). A frequent problem in CD is the discrimination of fever caused by exacerbated bowel inflammation or IAA.

METHODS

A total of 80 CD patients complaining with fever episodes were included prospectively. PCT, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WBC) were evaluated on admission. IAA was identified based on image studies and response to antibiotic therapy by physicians blind to the serum PCT level. At last, correlation between serum PCT level and patients' disease activity was also investigated.

RESULTS

Sixteen patients were identified with IAA, which showed significantly higher serum PCT level when compared with those patients who have no IAA (0.505 ng/ml vs 0.112 ng/ml, p < 0.01). PCT is a better biomarker of IAA in CD patients compared with CRP, ESR and WBC (AUC = 0.954, 0.757, 0.771 and 0.554, respectively). And the cutoff value for PCT in differentiating patients with and without IAA was 0.35 ng/ml. Correlation between serum PCT level and CDAI score (r = 0.575) was weaker than that of CRP and ESR (r = 0.628 and 0.634 respectively), but stronger than that of WBC (r = 0.162).

CONCLUSION

PCT can be an additional marker for detecting IAA in CD patients with fever episodes, and may serve as a new serological marker of disease activity.

Laparoscopy improves clinical outcome of gastrointestinal fistula caused by Crohn's disease

BACKGROUND

Benefits of laparoscopic surgery in the management of gastrointestinal fistula caused by Crohn disease need to be fully elucidated. We conducted this retrospective study to investigate the safety and feasibility and emphasize the advantages of laparoscopy compared with that of laparotomy for patients with gastrointestinal fistula caused by Crohn disease.

MATERIALS AND METHODS

A total of 1213 patients with gastrointestinal fistula in our center were screened, and 318 qualified patients were enrolled and divided into laparoscopy (n = 122) and laparotomy (n = 196) groups. Postoperative complications, length of hospital stay, systemic stress responses to surgery, postoperative mortality, and economic burden were collected and compared.

RESULTS

A total of 125 laparoscopic interventions were performed with a conversion rate of 20.0%. Fifteen versus 84 postoperative complications were obtained in laparoscopy and laparotomy groups, respectively (P = 0.0033). Total hospitalization was 22.7 d and 38.0 d in laparoscopy and laparotomy groups, respectively (P < 0.0001). Postoperative hospitalization was 10.9 d and 24.8 d in two groups, respectively (P < 0.0001). Elevation curve of serum C-reactive protein and procalcitonin in response to laparoscopy was significantly lower than that to laparotomy. Reduced postoperative mortality (P = 0.0292) and postoperative cost (P = 0.0292) were observed in laparoscopy instead of laparotomy group.

CONCLUSIONS

Laparoscopic approach is safe and feasible and could improve clinical outcome in gastrointestinal fistula patients with Crohn disease.

Clinical significance of serum procalcitonin in patients with ulcerative colitis

AIM: To investigate the association of serum procalcitonin (PCT) level with disease activity and inflammatory markers in ulcerative colitis (UC).

METHODS: Serum PCT levels, white blood cell count, platelet count, erythrocyte sedimentation rate (ESR), albumin, C-reactive protein (CRP) and interleukin-6 (IL-6) levels were analyzed in 31 patients with UC and 18 healthy volunteers. Severity assessments were based on the Truelove and Witts' severity index. Spearman's rank correlation and receiver operating characteristic (ROC) analysis were used to evaluate correlations between variables and diagnostic accuracy, respectively.

RESULTS: Serum PCT level in severe UC patients (n = 11, 0.426 μg/mL ± 0.506 μg/mL) was significantly higher than those in mild-to-moderate UC patients (n = 20, 0.079 μg/mL ± 0.085 μg/mL) and healthy volunteers (n = 18, 0.03 μg/mL ± 0.01 μg/mL) (P = 0.047, 0.027, respectively). Serum PCT level in UC patients was positively correlated with CRP levels, IL-6 levels and ESR, negatively with albumin levels (P < 0.05), but showed no statistically significant correlation with white blood cell count or platelet count (P > 0.05). PCT performed well in the prediction of UC, and was superior to CRP, ESR and white blood cell count for diagnosing severe UC. The area under the ROC curve was 0.895 (95%CI: 0.782-1.000, P < 0.001), 0.727 (95%CI: 0.548-0.906, P = 0.041), 0.856 (95%CI: 0.721-0.992, P = 0.001) and 0.665 (95%CI: 0.463-0.867, P = 0.138), respectively. A threshold of 0.1 μg/L for PCT may detect the most severe form of UC, and the sensitivity, specificity, predictive positive value and negative predictive value predictive were 90.91%, 80.00%, 71.43% and 94.12%, respectively.

CONCLUSION: Serum PCT level correlates with disease activity markers ESR and CRP in UC, and a cut-off of 0.1 μg/L could distinguish the most severe form of UC.

Clinical significance of serum procalcitonin in patients with ulcerative colitis

AIM: To investigate the association of procalcitonin (PCT) with ulcerative colitis (UC) activity.

METHODS: Serum PCT levels, C-reactive protein (CRP) levels, the erythrocyte sedimentation rate, and the white blood cell count were analyzed in 18 patients with UC and 11 healthy volunteers. Serum PCT levels were analyzed by an electrochemiluminescence immunoassay. Severity assessments were based on Truelove and Witts’ severity index. Correlation of serum PCT and CRP levels with UC activity was examined. Moreover, we assessed serum PCT and CRP levels in patients with a Mayo endoscopic subscore.

RESULTS: Serum PCT levels in severe UC patients (n = 7) (0.096 ± 0.034 ng/mL) were significantly higher than in mild-to-moderate UC patients (n = 11) (0.033 ± 0.012 ng/mL) and healthy volunteers (n = 11) (0.035 ± 0.005 ng/mL) (P = 0.0005 and P < 0.0001, respectively). In addition, there was no difference in serum PCT levels between mild-to-moderate UC patients and healthy volunteers. Interestingly, patients with a Mayo endoscopic subscore of 3 points displayed significantly increased levels of serum PCT (0.075 ± 0.043 ng/mL) compared with patients with a subscore of 2 points (0.03 ± 0.011 ng/mL) (P = 0.0302). Moreover, CRP levels in patients with severe UC or a Mayo endoscopic subscore of 3 points were not significantly higher than in patients with mild-to-moderate UC or a Mayo endoscopic subscore of 3 points.

CONCLUSION: Serum PCT levels were significantly correlated with UC activity.

The patient simple clinical colitis activity index (P-SCCAI) can detect ulcerative colitis (UC) disease activity in remission: a comparison of the P-SCCAI with clinician-based SCCAI and biological markers

AIM

To develop a patient-based Simple Clinical Colitis Activity Index (P-SCCAI) of ulcerative colitis (UC) activity and to compare it with the clinician-based SCCAI, C-reactive protein (CRP) and Physician's Global Assessment (PGA) of UC activity. Monitoring UC activity may give patients disease control and prevent unnecessary examinations.

METHODS

Consecutive UC patients randomly completed the P-SCCAI either before or after consultation. Gastroenterologists assessed patients' UC activity on the same day. Overall agreement between SCCAI and P-SCCAI was calculated with Spearman's Rho and Mann-Whitney U test. Agreement regarding active disease versus remission and agreement at domain level were calculated by percent agreement and kappa (κ).

RESULTS

149 (response rate 84.7%) UC patients participated. P-SCCAI and SCCAI showed a large correlation (rs=0.79). The medians (IQR) of the P-SCCAI (3.78;0-15) tended to be higher than those of the SCCAI (2.86;0-13), although this difference did not reach statistical significance (z=1.71| p=0.088). In 77% of the cases the difference between clinicians' and patients' scores was not clinically different (i.e.≤2). Percentage agreement between clinicians and patients, judging UC as active or in remission, was 87%, rs=0.66, κ=0.66, indicating a substantial agreement. In general patients tended to report more physical symptoms than clinicians. C-Reactive protein (CRP) was found to have a significant association with both P-SCCAI and SCCAI (κ=0.32, κ=0.39 respectively) as was PGA (κ=0.73 for both indices).

CONCLUSIONS

The P-SCCAI is a promising tool given its substantial agreement with the SCCAI and its feasibility. Therefore, P-SCCAI can complement SCCAI in clinical care and research.

Analysis of procalcitonin and CRP concentrations in serum of patients with chronic spontaneous urticaria

Background

Our previous findings showed the importance of analysing the peripheral markers of acute phase response (APR) activation, C-reactive protein (CRP) and IL-6 in the context of urticaria activity and severity. However, these biomarkers do not reliably differentiate between APR to infectious and the disease severity.

Aim

In order to investigate a possible association between the immune-inflammatory activation markers CRP and procalcitonin (PCT).

Methods

Serum PCT and CRP concentrations were measured in patients with CU of varying severity as well as in healthy subjects.

Results

Serum PCT and CRP concentrations were significantly increased in more severe CU patients when compared to healthy controls and mild CU, and within the CU population there was a significant correlation between concentrations of PCT and CRP. Serum PCT concentrations remained within normal ranges in most CU patients and were only slightly elevated in some severe CU cases.

Conclusions

PCT serum concentration may be only slightly elevated in some cases of severe CU. Upregulation of PCT synthesis accompanied by parallel changes in CRP concentration reflects a low-grade systemic inflammatory response in CU. PCT should be considered as a better marker than CRP to distinguish between APR to infection and an active non-specific urticarial inflammation.