Validity of the urinary trypsinogen-2 test in the diagnosis of acute pancreatitis

Current trends in acute pancreatitis: Diagnostic and therapeutic challenges

Acute pancreatitis (AP) is an inflammatory disease of the pancreas, which can progress to severe AP, with a high risk of death. It is one of the most complicated and clinically challenging of all disorders affecting the abdomen. The main causes of AP are gallstone migration and alcohol abuse. Other causes are uncommon, controversial and insufficiently explained. The disease is primarily characterized by inappropriate activation of trypsinogen, infiltration of inflammatory cells, and destruction of secretory cells. According to the revised Atlanta classification, severity of the disease is categorized into three levels: Mild, moderately severe and severe, depending upon organ failure and local as well as systemic complications. Various methods have been used for predicting the severity of AP and its outcome, such as clinical evaluation, imaging evaluation and testing of various biochemical markers. However, AP is a very complex disease and despite the fact that there are of several clinical, biochemical and imaging criteria for assessment of severity of AP, it is not an easy task to predict its subsequent course. Therefore, there are existing controversies regarding diagnostic and therapeutic modalities, their effectiveness and complications in the treatment of AP. The main reason being the fact, that the pathophysiologic mechanisms of AP have not been fully elucidated and need to be studied further. In this editorial article, we discuss the efficacy of the existing diagnostic and therapeutic modalities, complications and treatment failure in the management of AP.

Diagnosis and Treatment of Acute Pancreatitis

The pancreas is a glandular organ that is responsible for the proper functioning of the digestive and endocrine systems, and therefore, it affects the condition of the entire body. Consequently, it is important to effectively diagnose and treat diseases of this organ. According to clinicians, pancreatitis—a common disease affecting the pancreas—is one of the most complicated and demanding diseases of the abdomen. The classification of pancreatitis is based on clinical, morphologic, and histologic criteria. Medical doctors distinguish, inter alia, acute pancreatitis (AP), the most common causes of which are gallstone migration and alcohol abuse. Effective diagnostic methods and the correct assessment of the severity of acute pancreatitis determine the selection of an appropriate treatment strategy and the prediction of the clinical course of the disease, thus preventing life-threatening complications and organ dysfunction or failure. This review collects and organizes recommendations and guidelines for the management of patients suffering from acute pancreatitis.

Usefulness of urinary trypsinogen-2 and trypsinogen activation peptide in acute pancreatitis: A multicenter study in Japan

BACKGROUND

Rapid urinary trypsinogen-2 dipstick test and levels of urinary trypsinogen-2 and trypsinogen activation peptide (TAP) concentration have been reported as prognostic markers for the diagnosis of acute pancreatitis.

AIM

To reconfirm the validity of all these markers in the diagnosis of acute pancreatitis by undertaking a multi-center study in Japan.

METHODS

Patients with acute abdominal pain were recruited from 17 medical institutions in Japan from April 2009 to December 2012. Urinary and serum samples were collected twice, at enrollment and on the following day for measuring target markers. The diagnosis and severity assessment of acute pancreatitis were assessed based on prognostic factors and computed tomography (CT) Grade of the Japanese Ministry of Health, Labour, and Welfare criteria.

RESULTS

A total of 94 patients were enrolled during the study period. The trypsinogen-2 dipstick test was positive in 57 of 78 patients with acute pancreatitis (sensitivity, 73.1%) and in 6 of 16 patients with abdominal pain but without any evidence of acute pancreatitis (specificity, 62.5%). The area under the curve (AUC) score of urinary trypsinogen-2 according to prognostic factors was 0.704, which was highest in all parameter. The AUC scores of urinary trypsinogen-2 and TAP according to CT Grade were 0.701 and 0.692, respectively, which shows higher than other pancreatic enzymes. The levels of urinary trypsinogen-2 and TAP were significantly higher in patients with extended extra-pancreatic inflammation as evaluated by CT Grade.

CONCLUSION

We reconfirmed urinary trypsinogen-2 dipstick test is useful as a marker for the diagnosis of acute pancreatitis. Urinary trypsinogen-2 and TAP may be considered as useful markers to determine extra-pancreatic inflammation in acute pancreatitis.

A Clinical Model for the Early Diagnosis of Acute Pancreatitis in the Emergency Department

OBJECTIVE

This study aimed to develop a diagnostic model that predicts acute pancreatitis (AP) risk before imaging.

METHODS

Emergency department patients with serum lipase elevated to 3 times the upper limit of normal or greater were identified retrospectively (September 1, 2013-August 31, 2015). An AP diagnosis was established by expert review of full hospitalization records. Candidate predictors included demographic and clinical characteristics at presentation. Using a derivation set, a multivariable logistic regression model and corresponding point-based scoring system was developed to predict AP. Discrimination accuracy and calibration were assessed in a separate validation set.

RESULTS

In 319 eligible patients, 182 (57%) had AP. The final model (area under curve, 0.92) included 8 predictors: number of prior AP episodes; history of cholelithiasis; no abdominal surgery (prior 2 months); time elapsed from symptom onset; pain localized to epigastrium, of progressively worsening severity, and severity level at presentation; and extent of lipase elevation. At a diagnostic risk threshold of 8 points or higher (≥99%), the model identified AP with a sensitivity of 45%, and a specificity and a positive predictive value of 100%.

CONCLUSIONS

In emergency department patients with lipase elevated to 3 times the upper limit of normal or greater, this model helps identify AP risk before imaging. Prospective validation studies are needed to confirm diagnostic accuracy.

Serial-omics characterization of equine urine

Horse urine is easily collected and contains molecules readily measurable using mass spectrometry that can be used as biomarkers representative of health, disease or drug tampering. This study aimed at analyzing microliter levels of horse urine to purify, identify and quantify proteins, polar metabolites and non-polar lipids. Urine from a healthy 12 year old quarter horse mare on a diet of grass hay and vitamin/mineral supplements with limited pasture access was collected for serial-omics characterization. The urine was treated with methyl tert-butyl ether (MTBE) and methanol to partition into three distinct layers for protein, non-polar lipid and polar metabolite content from a single liquid-liquid extraction and was repeated two times. Each layer was analyzed by high performance liquid chromatography—high resolution tandem mass spectrometry (LC-MS/MS) to obtain protein sequence and relative protein levels as well as identify and quantify small polar metabolites and lipids. The results show 46 urine proteins, many related to normal kidney function, structural and circulatory proteins as well as 474 small polar metabolites but only 10 lipid molecules. Metabolites were mostly related to urea cycle and ammonia recycling as well as amino acid related pathways, plant diet specific molecules, etc. The few lipids represented triglycerides and phospholipids. These data show a complete mass spectrometry based—omics characterization of equine urine from a single 333 μL mid-stream urine aliquot. These omics data help serve as a baseline for healthy mare urine composition and the analyses can be used to monitor disease progression, health status, monitor drug use, etc.

Serum amylase and lipase and urinary trypsinogen and amylase for diagnosis of acute pancreatitis

BACKGROUND

The treatment of people with acute abdominal pain differs if they have acute pancreatitis. It is important to know the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis, so that an informed decision can be made as to whether the person with abdominal pain has acute pancreatitis. There is currently no Cochrane review of the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis.

OBJECTIVES

To compare the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase, either alone or in combination, in the diagnosis of acute pancreatitis in people with acute onset of a persistent, severe epigastric pain or diffuse abdominal pain.

SEARCH METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, National Institute for Health Research (NIHR HTA and DARE), and other databases until March 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase.

SELECTION CRITERIA

We included all studies that evaluated the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis. We excluded case-control studies because these studies are prone to bias. We accepted any of the following reference standards: biopsy, consensus conference definition, radiological features of acute pancreatitis, diagnosis of acute pancreatitis during laparotomy or autopsy, and organ failure. At least two review authors independently searched and screened the references located by the search to identify relevant studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from the included studies. The thresholds used for the diagnosis of acute pancreatitis varied in the trials, resulting in sparse data for each index test. Because of sparse data, we used -2 log likelihood values to determine which model to use for meta-analysis. We calculated and reported the sensitivity, specificity, post-test probability of a positive and negative index test along with 95% confidence interval (CI) for each cutoff, but have reported only the results of the recommended cutoff of three times normal for serum amylase and serum lipase, and the manufacturer-recommended cutoff of 50 mg/mL for urinary trypsinogen-2 in the abstract.

MAIN RESULTS

Ten studies including 5056 participants met the inclusion criteria for this review and assessed the diagnostic accuracy of the index tests in people presenting to the emergency department with acute abdominal pain. The risk of bias was unclear or high for all of the included studies. The study that contributed approximately two-thirds of the participants included in this review was excluded from the results of the analysis presented below due to major concerns about the participants included in the study. We have presented only the results where at least two studies were included in the analysis.Serum amylase, serum lipase, and urinary trypsinogen-2 at the standard threshold levels of more than three times normal for serum amylase and serum lipase, and a threshold of 50 ng/mL for urinary trypsinogen-2 appear to have similar sensitivities (0.72 (95% CI 0.59 to 0.82); 0.79 (95% CI 0.54 to 0.92); and 0.72 (95% CI 0.56 to 0.84), respectively) and specificities (0.93 (95% CI 0.66 to 0.99); 0.89 (95% CI 0.46 to 0.99); and 0.90 (95% CI 0.85 to 0.93), respectively). At the median prevalence of 22.6% of acute pancreatitis in the studies, out of 100 people with positive test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 74 (95% CI 33 to 94); 68 (95% CI 21 to 94); and 67 (95% CI 57 to 76) people have acute pancreatitis, respectively; out of 100 people with negative test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 8 (95% CI 5 to 12); 7 (95% CI 3 to 15); and 8 (95% CI 5 to 13) people have acute pancreatitis, respectively. We were not able to compare these tests formally because of sparse data.

AUTHORS' CONCLUSIONS

As about a quarter of people with acute pancreatitis fail to be diagnosed as having acute pancreatitis with the evaluated tests, one should have a low threshold to admit the patient and treat them for acute pancreatitis if the symptoms are suggestive of acute pancreatitis, even if these tests are normal. About 1 in 10 patients without acute pancreatitis may be wrongly diagnosed as having acute pancreatitis with these tests, therefore it is important to consider other conditions that require urgent surgical intervention, such as perforated viscus, even if these tests are abnormal.The diagnostic performance of these tests decreases even further with the progression of time, and one should have an even lower threshold to perform additional investigations if the symptoms are suggestive of acute pancreatitis.

Value of serum amylase and lipase in early diagnosis of acute pancreatitis: A Meta-analysis

AIM: To systematically assess the value of serum amylase and lipase in the early diagnosis of acute pancreatitis (AP) to provide the best evidence for clinical decision-making.

METHODS: Medline, EMBASE, Science Direct, Springer link, CBM, Cnki, Wan fang and VIP database were electronically searched between January 2004 and November 2013 to collect the articles assessing serum amylase and lipase in early diagnosis of AP. Quality assessment was made using the QUADAS scale. The Meta-Disc1.4 software was used to assess the heterogeneity of included articles, plot the SROC curve, and calculate the summary sensitivity and specificity.

RESULTS: A total of 22 articles were included, including 16 Chinese studies, and 6 English articles. The summary sensitivity, summary specificity and the area under the SROC curve of serum amylase in diagnosing AP were 73% (95%CI: 71%-75%), 87% (95%CI: 85%-88%) and 0.8758, respectively. The corresponding values for serum lipase were 89% (95%CI: 87%-90%), 88% (95%CI: 86%-89%) and 0.9430.

CONCLUSION: Serum lipase has higher diagnostic value in early diagnosis of AP than serum amylase. Serum lipase can be used as an early diagnostic marker for AP.

Criteria for the diagnosis and severity stratification of acute pancreatitis

Recent diagnostic and therapeutic progress for severe acute pancreatitis (SAP) remarkably decreased the case-mortality rate. To further decrease the mortality rate of SAP, it is important to precisely evaluate the severity at an early stage, and initiate appropriate treatment as early as possible. Research Committee of Intractable Diseases of the Pancreas in Japan developed simpler criteria combining routinely available data with clinical signs. Severity can be evaluated by laboratory examinations or by clinical signs, reducing the defect values of the severity factors. Moreover, the severity criteria considered laboratory/clinical severity scores and contrast-enhanced computed tomography (CE-CT) findings as independent risk factors. Thus, CE-CT scans are not necessarily required to evaluate the severity of acute pancreatitis. There was no fatal case in mild AP diagnosed by the CE-CT severity score, whereas case-mortality rate in those with SAP was 14.8%. Case-mortality of SAP that fulfilled both the laboratory/clinical and the CE-CT severity criteria was 30.8%. It is recommended, therefore, to perform CE-CT examination to clarify the prognosis in those patients who were diagnosed as SAP by laboratory/clinical severity criteria. Because the mortality rate of these patients with SAP is high, such patients should be transferred to advanced medical units.

Urinary trypsinogen-2 for diagnosing acute pancreatitis: a meta-analysis

BACKGROUND

Currently, serum amylase and lipase are the most popular laboratory markers for early diagnosis of acute pancreatitis with reasonable sensitivity and specificity. Urinary trypsinogen-2 (UT-2) has been increasingly used but its clinical value for the diagnosis of acute pancreatitis and post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis has not yet been systematically assessed.

DATA SOURCES

A comprehensive search was carried out using PubMed (MEDLINE), Embase, and Web of Science for clinical trials, which studied the usefulness of UT-2 as a diagnostic marker for acute pancreatitis. Sensitivity, specificity and the diagnostic odds ratios (DORs) with 95% confidence interval (CI) were calculated for each study and were compared with serum amylase and lipase. Summary receiver-operating curves were conducted and the area under the curve (AUC) was evaluated.

RESULTS

A total of 18 studies were included. The pooled sensitivity and specificity of UT-2 for the diagnosis of acute pancreatitis were 80% and 92%, respectively (AUC=0.96, DOR=65.63, 95% CI: 31.65-139.09). The diagnostic value of UT-2 was comparable to serum amylase but was weaker than serum lipase. The pooled sensitivity and specificity for the diagnosis of post-ERCP pancreatitis were 86% and 94%, respectively (AUC=0.92, DOR=77.68, 95% CI: 24.99-241.48).

CONCLUSIONS

UT-2 as a rapid test could be potentially used for the diagnosis of post-ERCP pancreatitis and to an extent, acute pancreatitis. Further studies are warranted to confirm these results.