Spot urine 5-hydroxyindoleacetic acid levels in the early diagnosis of acute appendicitis

Diagnostic performance of urinary 5-Hydroxyindoleacetic Acid in acute appendicitis: a systematic review and diagnostic test accuracy meta-analysis

OBJECTIVES

This study aimed to analyze the diagnostic performance of urinary 5-Hydroxyindoleacetic Acid (5-HIAA) in acute appendicitis (AA).

METHODS

This review was registered in PROSPERO (CRD42023399541). We included prospective or retrospective original clinical studies evaluating the diagnostic performance of 5-HIAA in AA. A search was conducted in PubMed, Web of Science, Scopus and OVID. Search terms and keywords were: (appendicitis OR acute appendicitis) AND (5-HIAA OR 5-Hydroxyindoleacetic acid OR serotonin metabolite). Two independent reviewers selected the articles and extracted relevant data. Methodological quality was assessed using the QUADAS2 index. A synthesis of the results, standardization of the metrics, and a random-effect meta-analysis were performed. Additionally, a coupled forest plot and a diagnostic test accuracy meta-analysis (DTA) were performed.

RESULTS

Twelve studies with data from 1467 participants (724 patients with a confirmed diagnosis of AA and 743 controls) were included in this review. The random-effect meta-analysis of urinary 5-HIAA (AA vs controls) included 7 articles (352 AA and 258 controls) and resulted in a significant mean difference [95% CI] of 23.30 [15.82-30.77] μmol/L (p < 0.001). The DTA meta-analysis of urinary 5-HIAA included 8 articles and resulted in a pooled sensitivity [95% CI] of 68.6 [44.1-85.9]% and a pooled specificity [95% CI] of 82 [54.7-94.5]%.

CONCLUSIONS

Although the evidence is heterogeneous and limited, urinary 5-HIAA emerges as a potential non-invasive diagnostic tool for AA. Urinary 5-HIAA does not seem to be a useful biomarker to distinguish between NCAA and CAA. Future prospective studies with a large sample size and a rigorous design are necessary to validate these findings.

TRIAL REGISTRATION

PROSPERO (CRD42023399541).

Biomarker of urinary 5-HIAA as a valuable predictor of acute appendicitis

Background

Serotonin-containing cells are abundantly found in the appendix. Studies have shown that acute appendicitis is likely to be characterized by altered urinary 5-hydroxyindole acetic acid (5-HIAA), an active serotonin metabolite. The aim of this study is to investigate the diagnostic potential of 5-HIAA as a biomarker for acute appendicitis.

Method

This cross-sectional study enrolled patients referred at the Madani Hospital, with right iliac fossa pain, suspected to having the acute appendicitis. Before the initiation of the basic treatment and surgery, urine samples were obtained from the patients. Enzyme-linked immunosorbent assay (ELISA) was used for the analysis of 5-HIAA urinary levels. The obtained data were statistically analyzed using SPSS v18.

Results

Of 129 patients included in the study with the mean age of 29 years, 62 (48.1%) were men and 67 (51.9%) were women. Appendectomy was performed in 96 patients, where 81 cases were that of acute appendicitis. The mean levels of 5-HIAA in acute appendicitis group and in the negative appendectomy group was not statistically significant. The sensitivity of the test was 54.3% based on 7.4 ​μmol/L as cut-off %-HIAA value.

Conclusion

Our study reports that 5-HIAA urine concentration is not a reliable diagnostic marker for the diagnosis of acute appendicitis.

Discovery of Urinary Proteomic Signature for Differential Diagnosis of Acute Appendicitis

Acute appendicitis is one of the most common acute abdomens, but the confident preoperative diagnosis is still a challenge. In order to profile noninvasive urinary biomarkers that could discriminate acute appendicitis from other acute abdomens, we carried out mass spectrometric experiments on urine samples from patients with different acute abdomens and evaluated diagnostic potential of urinary proteins with various machine-learning models. Firstly, outlier protein pools of acute appendicitis and controls were constructed using the discovery dataset (32 acute appendicitis and 41 control acute abdomens) against a reference set of 495 normal urine samples. Ten outlier proteins were then selected by feature selection algorithm and were applied in construction of machine-learning models using naïve Bayes, support vector machine, and random forest algorithms. The models were assessed in the discovery dataset by leave-one-out cross validation and were verified in the validation dataset (16 acute appendicitis and 45 control acute abdomens). Among the three models, random forest model achieved the best performance: the accuracy was 84.9% in the leave-one-out cross validation of discovery dataset and 83.6% (sensitivity: 81.2%, specificity: 84.4%) in the validation dataset. In conclusion, we developed a 10-protein diagnostic panel by the random forest model that was able to distinguish acute appendicitis from confusable acute abdomens with high specificity, which indicated the clinical application potential of noninvasive urinary markers in disease diagnosis.

Does elevated urinary 5-hydroxyindole acetic acid level predict acute appendicitis in children?

BACKGROUND

Acute appendicitis is the most common abdominal surgical emergency in children, and appendectomy is the most frequent acute abdominal operation. Prompt diagnosis and surgical treatment are required to reduce the risk of perforation and prevent complications, especially in small children. Enterochromaffin cells that contain large amounts of serotonin are mostly located in the distal appendix. Serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) could therefore be a marker for acute appendicitis.

OBJECTIVE

We tested urinary 5-HIAA concentrations in spot urine samples from children with acute appendicitis.

METHODS

We enrolled 93 patients who underwent surgery for suspicion of acute appendicitis. The diagnosis was made intraoperatively and confirmed histopathologically. Additionally, urine samples from 102 healthy children were collected as controls. Their 5-HIAA was measured using high-performance liquid chromatography.

RESULTS

Acute appendicitis was diagnosed in 81 patients, whereas there were other explanations for abdominal pain in the remaining 12 patients in the non-appendicitis group. The control group comprised 102 healthy children. Considering the median of all measured 5-HIAA values as the cut-off, we analysed the proportions of patients with elevated values in all the groups. Our analysis showed that statistically there was no significant difference in the distribution of percentages among the groups. The area under the curve for 5-HIAA was 0.55 (95% CI 0.47 to 0.62) with sensitivity and specificity 60.4% and 48.9%, respectively.

CONCLUSIONS

Urine 5-HIAA concentration measured in spot samples is not a reliable method for diagnosing acute appendicitis in children.

Serum, Saliva, and Urine Irisin with and Without Acute Appendicitis and Abdominal Pain

A 112-amino-acid protein irisin (IRI) is widely expressed in many organs, but we currently do not know whether appendix tissue and blood cells express it. If appendix tissue and neutrophil cells express IRI, measuring its concentration in biological fluids might be helpful in the diagnosis of acute appendicitis (AA), since neutrophil cells are the currently gold-standard laboratory parameters for the diagnosis of AA. Therefore, the purpose of this study was to investigate the suitability of enzyme-linked immunosorbent assay-based measurements of the proposed myokine IRI for the discrimination of patients with AA from those with acute abdominal pain (AP) and healthy controls. Moreover, immunoreactivity to IRI was investigated in appendix tissues and blood cells. Samples were collected on admission (T1), 24 hours (T2), and 72 hours (T3) postoperatively from patients with suspected AA and from patients with AP corresponding to T1–T3, whereas control subject blood was once corresponding to T1. IRI was measured in serum, saliva, and urine by using enzyme-linked immunosorbent assay, whereas in appendix tissue and blood cells, IRI was detected by immunohistohcemistry. Appendix tissue and blood cells (except for erythrocytes) are new sources of IRI. Basal saliva, urine, and serum levels were higher in children with AA compared with postoperative levels (T2) that start to decline after surgery. This is in line with the finding that IRI levels are higher in children with AA when compared with those with AP or control subject levels, most likely due to a large infiltration of neutrophil cells in AA that release its IRI into body fluids. Measurement of IRI in children with AA parallels the increase or decrease in the neutrophil count. This new finding shows that the measurement of IRI and neutrophil count can together improve the diagnosis of AA, and it can distinguish it from AP. IRI can be a candidate marker for the diagnosis of AA and offers an additional parameter to neutrophil count. The promising receiving operating curve results indicate the following sensitivities and specificities, respectively, for IRI: serum 90% and 55%, saliva 90% and 60%, and urine 90% and 50%. Serum neutrophil count gave a sensitivity of 90% and a specificity of 90%. This promising result now needs to be confirmed in a larger group of patients.

Spot urinary 5-hydroxyindoleacetic acid is not an ideal diagnostic test for acute appendicitis

BACKGROUND AND PURPOSE OF THE STUDY

There is growing evidence to suggest the use of urinary 5-hydroxyindoleacetic acid (5-HIAA) test to help with the diagnosis of appendicitis. The aim of our study was to establish whether urinary 5-HIAA could be used as an effective diagnostic test for acute appendicitis.

DESIGN AND METHODS

A prospective double-blinded study was carried out from December 2014 to October 2015. Patients admitted to the emergency surgical ward of a teaching hospital with suspected appendicitis were included in the study. The diagnostic accuracy of the test was measured by receiver operating characteristic curve.

RESULTS

Ninety-seven patients were divided into 2 groups: acute appendicitis (n=38) and other diagnosis (n=59). The median value of urinary 5-HIAA was 24.19μmol/L (range, 5.39-138.27) for acute appendicitis vs 18.87μmol/L (range, 2.27-120.59) for other diagnosis group (P=.038). The sensitivity and specificity of urinary 5-HIAA at a cutoff value of 19μmol/L were 71% and 50%, respectively. Receiver operating characteristic analysis showed that the area under curve was 0.64 (confidence interval [CI], 0.513-0.737) for urinary 5-HIAA, which was lower than white blood cell count (0.69; CI, 0.574-0.797), neutrophil count (0.68; CI, 0.565-0.792), and C-reactive protein (0.76; CI, 0.657-0.857). There was no significant difference in the median values of 5-HIAA between different grades of severity of appendicitis (P=.704).

CONCLUSION

Urinary 5-HIAA is not an ideal test for the diagnosis of acute appendicitis.

Neutrophil gelatinase-associated lipocal in protein levels as an acute appendicitis biomarker in children

OBJECTIVE

Appendicitis is very commonly encountered in emergency clinics. There is an urgent need for early and accurate predictive biomarkers of appendicitis in order to save lives, because currently-available biomarkers are imprecise and their delayed response impairs the ability of emergency doctors and pediatric surgeons to provide timely and potentially effective therapies. This study was performed to determine whether changes in the blood levels of neutrophil gelatinase-associated lipocalin (NGAL) can help to diagnose acute appendicitis in children and distinguish acute appendicitis from abdominal pain.

METHODS

Sixty children were enrolled and divided into three groups, with 20 patients per group: Group 1 (patients with appendicitis), Group 2 (patients with abdominal pain) and Group 3 (control). Blood NGAL levels were determined by ELISA.

RESULTS

The basal average serum NGAL levels were 8.2 ng/ml for Group 1, 3.9 ng/ml for Group 2, and 3.3 ng/ml for Group 3. Twenty-four and 72 h after surgery the levels were 5.1 and 2.8 ng/ml, respectively, in Group 1, 2.9 and 2.8 ng/ml in Group 2, and 2.6, 2.7 ng/ml in Group 3. Setting the cut-off point to 7 generated an area under the receiving operating curve (ROC) curve at 95 % confidence interval with 77.3 % sensitivity and 97.4 % specificity.

CONCLUSION

These data indicate a significant difference in NGAL values between basal and postoperative measurements in appendicitis patients (p < 0.05). The ROC curve results showed that NGAL is a promising novel biomarker for the differential diagnosis of acute appendicitis from abdominal pain.

Determination of urinary 5-hydroxyindoleacetic acid by combining Dμ-SPE using carbon coated TiO2 nanotubes and LC–MS/MS

Background: In this article, carbon coated titanium dioxide nanotubes (TiO2-NT@C) are employed for the determination of 5-hydroxyindole-3-acetic acid in urine by LC–MS/MS. Results: All the variables involved in the extraction have been studied and optimized in depth. The method has been analytically characterized on the basis of its linearity, accuracy, sensitivity and precision. The LOD is 155.8 μg/l while the repeatability and the reproducibility, expressed as RSD, are better than 5.42 and 5.25%, respectively. The obtained relative recovery is 115%. Conclusion: TiO2-NT@C permit the efficient extraction of 5-hydroxyindole-3-acetic acid from complex biological samples such as urine allowing its sensitive determination by LC–MS/MS.

Diagnostic characteristics of S100A8/A9 in a multicenter study of patients with acute right lower quadrant abdominal pain

OBJECTIVES

Over the past decade, clinicians have become increasingly reliant on computed tomography (CT) for the evaluation of patients with suspected acute appendicitis. To limit the radiation risks and costs of CT, investigators have searched for biomarkers to aid in diagnostic decision-making. We evaluated one such biomarker, calprotectin or S100A8/A9, and determined the diagnostic performance characteristics of a developmental biomarker assay in a multicenter investigation of patients presenting with acute right lower quadrant abdominal pain.

METHODS

This was a prospective, double-blinded, single-arm, multicenter investigation performed in 13 emergency departments (EDs) from August 2009 to April 2010 of patients presenting with acute right lower quadrant abdominal pain. Plasma samples were tested using the investigational S100A8/A9 assay. The primary outcome of acute appendicitis was determined by histopathology for patients undergoing appendectomy or 2-week telephone follow-up for patients discharged without surgery. The sensitivity, specificity, negative likelihood ratio (LR-), and positive likelihood ratio (LR+) of the biomarker assay were calculated using the prespecified cutoff value of 14 units. A post hoc stability study was performed to investigate the potential effect of time and courier transport on the measured value of the S100A8/A9 assay test results.

RESULTS

Of 1,052 enrolled patients, 848 met criteria for analysis. The median age was 24.5 years (interquartile range [IQR] = 16-38 years), 57% were female, and 50% were white. There was a 27.5% prevalence of acute appendicitis. The sensitivity and specificity for the investigational S100A8/A9 assay in diagnosing acute appendicitis were estimated to be 96% (95% confidence interval [CI] = 93% to 98%) and 16% (95% CI = 13% to 19%), respectively. The LR- ratio was 0.24 (95% CI = 0.12 to 0.47), and the LR+ was 1.14 (95% CI = 1.10 to 1.19). The post hoc stability study demonstrated that in the samples that were shipped, the estimated time coefficient was 7.6 × 10(-3) ± 2.0 × 10(-3) log units/hour, representing an average increase of 43% in the measured value over 48 hours; in the samples that were not shipped, the estimated time coefficient was 2.5 × 10(-3) ± 0.4 × 10(-3) log units/hour, representing a 13% increase on average in the measured value over 48 hours, which was the maximum delay allowed by the study protocol. Thus, adjusting the cutoff value of 14 units by the magnitude of systematic inflation observed in the stability study at 48 hours would result in a new cutoff value of 20 units and a "corrected" sensitivity and specificity of 91 and 28%, respectively.

CONCLUSIONS

In patients presenting with acute right lower quadrant abdominal pain, we found the investigational enzyme-linked immunosorbent assay (ELISA) test for S100A8/A9 to perform with high sensitivity but very limited specificity. We found that shipping effect and delay in analysis resulted in a subsequent rise in test values, thereby increasing the sensitivity and decreasing the specificity of the test. Further investigation with hospital-based laboratory analyzers is the next critical step for determining the ultimate clinical utility of the ELISA test for S100A8/A9 in ED patients presenting with acute right lower quadrant abdominal pain.

Is urinary 5-hydroxyindoleacetic acid helpful for early diagnosis of acute appendicitis?

OBJECTIVE

Acute appendicitis is the most common abdominal emergency in children and young adults. There are a lot of serotonin-containing cells in the appendix, which release serotonin into the bloodstream in response to inflammation. Consequently, serotonin is converted to 5-hydroxyindoleacetic acid (5-HIAA) and secreted into the urine. On this basis, urinary 5-HIAA could be a marker for acute appendicitis. In this study, we investigated the value of 5-HIAA levels in spot urine in the diagnosis of acute appendicitis.

METHODS

The urinary 5-HIAA was measured by an enzyme-linked immunosorbent assay in the spot urine of 70 patients who presented to the emergency department with a clinical picture of acute appendicitis. Urine concentration results were correlated to final histopathologic reports, and the diagnostic value of this factor was measured.

RESULTS

Diagnosis of appendicitis was confirmed by histopathologic reports in 59 of 70 patients with presumptive diagnosis of appendicitis. Considering 5.25 mg/L as the cutoff point for urinary 5-HIAA, 28 patients had high urinary 5-HIAA levels, whereas 42 patients had values within reference range. The sensitivity and specificity of this test was 44% and 81%, respectively.

CONCLUSIONS

The measurement of urinary 5-HIAA levels is not an ideal diagnostic tool for ruling out or determination of acute appendicitis.

Discovery and validation of urine markers of acute pediatric appendicitis using high-accuracy mass spectrometry

STUDY OBJECTIVE

Molecular definition of disease has been changing all aspects of medical practice, from diagnosis and screening to understanding and treatment. Acute appendicitis is among many human conditions that are complicated by the heterogeneity of clinical presentation and shortage of diagnostic markers. Here, we sought to profile the urine of patients with appendicitis, with the goal of identifying new diagnostic markers.

METHODS

Candidate markers were identified from the urine of children with histologically proven appendicitis by using high-accuracy mass spectrometry proteome profiling. These systemic and local markers were used to assess the probability of appendicitis in a blinded, prospective study of children being evaluated for acute abdominal pain in our emergency department. Tests of performance of the markers were evaluated against the pathologic diagnosis and histologic grade of appendicitis.

RESULTS

Test performance of 57 identified candidate markers was studied in 67 patients, with median age of 11 years, 37% of whom had appendicitis. Several exhibited favorable diagnostic performance, including calgranulin A (S100-A8), alpha-1-acid glycoprotein 1 (orosomucoid), and leucine-rich alpha-2-glycoprotein (LRG), with the receiver operating characteristic area under the curve and values of 0.84 (95% confidence interval [CI] 0.72 to 0.95), 0.84 (95% CI 0.72 to 0.95), and 0.97 (95% CI 0.93 to 1.0), respectively. LRG was enriched in diseased appendices, and its abundance correlated with severity of appendicitis.

CONCLUSION

High-accuracy mass spectrometry urine proteome profiling allowed identification of diagnostic markers of acute appendicitis. Usage of LRG and other identified biomarkers may improve the diagnostic accuracy of clinical evaluations of appendicitis.