A prospective study of serum pancreatic elastase-1 in the diagnosis and assessment of acute pancreatitis

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.

Practical Interpretation and Application of Exocrine Pancreatic Testing in Small Animals

The pancreas remains a difficult organ to evaluate using laboratory methods alone. No single laboratory test is diagnostic of pancreatitis (chronic or acute) without other diagnostic modalities concurring with the diagnosis or ruling out other diseases. The diagnosis of pancreatitis is particularly difficult in cats, and pancreatitis often occurs with other diseases. The use of pancreatic cytology may be useful in diagnosing both inflammation and neoplasia. Exocrine pancreatic insufficiency (EPI) can be relatively easily diagnosed when clinically manifested by the measurement of trypsinlike immunoreactivity. Diagnosis is more difficult when EPI is subclinical.

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.

Early diagnosis of asparaginase-associated pancreatitis based on elevated serum elastase-1 levels: Case reports

L-asparaginase (L-asp) is a well-known anticancer agent used in the treatment of acute lymphoblastic leukemia (ALL) in children. However, it is also known to induce several acute complications, such as acute pancreatitis. This is a presentation of two pediatric acute lymphoblastic leukemia (ALL) cases of asparaginase-associated pancreatitis (AAP) diagnosed at an early stage based on elevated serum elastase-1 levels, in the presence of normal serum amylase levels. Early diagnosis and treatment of AAP, although imperative, is occasionally difficult if only standard diagnostic procedures are followed. Elastase-1 is a potentially useful marker for the early diagnosis of AAP. Therefore, the measurement of elastase-1 levels, in addition to amylase and lipase levels, is recommended in L-asp-treated patients.

Bioinformatic identification of proteins with tissue-specific expression for biomarker discovery

BACKGROUND

There is an important need for the identification of novel serological biomarkers for the early detection of cancer. Current biomarkers suffer from a lack of tissue specificity, rendering them vulnerable to non-disease-specific increases. The present study details a strategy to rapidly identify tissue-specific proteins using bioinformatics.

METHODS

Previous studies have focused on either gene or protein expression databases for the identification of candidates. We developed a strategy that mines six publicly available gene and protein databases for tissue-specific proteins, selects proteins likely to enter the circulation, and integrates proteomic datasets enriched for the cancer secretome to prioritize candidates for further verification and validation studies.

RESULTS

Using colon, lung, pancreatic and prostate cancer as case examples, we identified 48 candidate tissue-specific biomarkers, of which 14 have been previously studied as biomarkers of cancer or benign disease. Twenty-six candidate biomarkers for these four cancer types are proposed.

CONCLUSIONS

We present a novel strategy using bioinformatics to identify tissue-specific proteins that are potential cancer serum biomarkers. Investigation of the 26 candidates in disease states of the organs is warranted.

Specificity and sensitivity of serum canine pancreatic elastase-1 concentration in the diagnosis of pancreatitis

The aim of the current study was to determine the sensitivity and specificity of serum canine pancreatic elastase-1 (cPE-1) for the diagnosis of pancreatitis in dogs. The study was prospective, assessing dogs presenting with clinical signs similar to pancreatitis. Sixty-one dogs were recruited (49 with pancreatic disease and 12 with non-pancreatic disease). There was no significant difference in serum cPE-1 between dogs with pancreatic disease and non-pancreatic disease. However, there was a significant difference in serum cPE-1 between severe acute pancreatitis and non-pancreatic disease. A cut-off value for serum cPE-1 > 17.24 ng/ml resulted in sensitivity of 61.4% and specificity of 91.7% for diagnosis of all types of pancreatic disease. The sensitivity rose to 65.85% and 78.26% for the diagnosis of all types of acute pancreatitis and severe acute pancreatitis, respectively. Serum cPE-1 is more sensitive at diagnosing severe acute pancreatitis than chronic or mild acute pancreatitis, and has a high positive likelihood ratio. Dogs with chronic pancreatitis tended to have lower serum cPE-1 concentration, suggesting decreased exocrine function.

New diagnostic criteria of acute pancreatitis

Practical guidelines for the diagnosis of acute pancreatitis are presented so that a rapid and adequate diagnosis can be made. When acute pancreatitis is suspected in patients with acute onset of abdominal pain and tenderness mainly in the upper abdomen, the diagnosis of acute pancreatitis is made on the basis of elevated levels of pancreatic enzymes in the blood and/or urine. Furthermore, other acute abdominal diseases are ruled out if local findings associated with pancreatitis are confirmed by diagnostic imaging. According to the diagnostic criteria established in Japan, patients who present with two of the following three manifestations are diagnosed as having acute pancreatitis: characteristic upper abdominal pain, elevated levels of pancreatic enzymes, and findings of ultrasonography (US), CT or MRI suggesting acute pancreatitis. Detection of elevated levels of blood pancreatic enzymes is crucial in the diagnosis of acute pancreatitis. Measurement of blood lipase is recommended, because it is reported to be superior to all other pancreatic enzymes in terms of sensitivity and specificity. For measurements of the blood amylase level widely used in Japan, it should be cautioned that, because of its low specificity, abnormal high values are also often obtained in diseases other than pancreatitis. The cut-off level of blood pancreatic enzymes for the diagnosis of acute pancreatitis is not able to be set because of lack of sufficient evidence and consensus to date. CT study is the most appropriate procedure to confirm image findings of acute pancreatitis. Elucidation of the etiology of acute pancreatitis should be continued after a diagnosis of acute pancreatitis. In the process of the etiologic elucidation of acute pancreatitis, judgment whether it is gallstone-induced or not is most urgent and crucial for deciding treatment policy including the assessment of whether endoscopic papillary treatment should be conducted or not. The diagnosis of gallstone-induced acute pancreatitis can be made by combining detection of elevated levels of bilirubin, transamylase (ALT, AST) and ALP detected by hematological examination and the visualization of gallstones by US.

JPN Guidelines for the management of acute pancreatitis: diagnostic criteria for acute pancreatitis

The currently used diagnostic criteria for acute pancreatitis in Japan are presentation with at least two of the following three manifestations: (1) acute abdominal pain and tenderness in the upper abdomen; (2) elevated levels of pancreatic enzyme in the blood, urine, or ascitic fluid; and (3) abnormal imaging findings in the pancreas associated with acute pancreatitis. When a diagnosis is made on this basis, other pancreatic diseases and acute abdomen can be ruled out. The purpose of this article is to review the conventional criteria and, in particular, the various methods of diagnosis based on pancreatic enzyme values, with the aim of improving the quality of diagnosis of acute pancreatitis and formulating common internationally agreed criteria. The review considers the following recommendations:

— Better even than the total blood amylase level, the blood lipase level is the best pancreatic enzyme for the diagnosis of acute pancreatitis and its differentiation from other diseases.

— A pivotal factor in the diagnosis of acute pancreatitis is identifying an increase in pancreatic enzymes in the blood.

— Ultrasonography (US) is also one of the procedures that should be performed in all patients with suspected acute pancreatitis.

— Magnetic resonance imaging (MRI) is one of the most important imaging procedures for diagnosing acute pancreatitis and its intraperitoneal complications.

— Computed tomography (CT) is also one of the most important imaging procedures for diagnosing acute pancreatitis and its intraabdominal complications. CT should be performed when a diagnosis of acute pancreatitis cannot be established on the basis of the clinical findings, results of blood and urine tests, or US, or when the etiology of the pancreatitis is unknown.

— When acute pancreatitis is suspected, chest and abdominal X-ray examinations should be performed to determine whether any abnormal findings caused by acute pancreatitis are present.

— Because the etiology of acute pancreatitis can have a crucial influence on both the treatment policy and severity assessment, it should be evaluated promptly and accurately. It is particularly important to differentiate between gallstone-induced acute pancreatitis, which requires treatment of the biliary system, and alcohol-induced acute pancreatitis, which requires a different form of treatment.

Role of macrophage migration inhibitory factor in acute lung injury in mice with acute pancreatitis complicated by endotoxemia

Acute pancreatitis accompanied by a subsequent infectious attack can often lead to multisystem organ dysfunction, including acute lung injury (ALI), but the molecular mechanisms are poorly defined. In this study, we explored the role of the priming insult by induction of cerulein pancreatitis, which was followed by the second attack due to endotoxemia, in the development of ALI in mice. Experiments revealed that LPS injection in mice with acute pancreatitis caused the development of ALI, as indicated by blood-gas derangements, pulmonary vascular hyperpermeability, increased inflammatory cell counts in bronchoalveolar lavage, and histologic lung damage. This was associated with the pancreatitis-induced increase in expression of macrophage migration inhibitory factor (MIF) in the lungs, together with elevated expression of Toll-like receptor (TLR)-4, both of which were inhibited by administration of anti-protease-activated receptor (PAR)-2 antibody. Furthermore, anti-MIF antibody treatment suppressed the pancreatitis-induced elevation of TLR-4 pulmonary expression. Genetic removal of MIF from mice resulted in less development of ALI in the setting of acute pancreatitis complicated by endotoxemia. These findings demonstrate that activation of protease-activated receptor-2 with trypsin, which can be released after pancreatitis induction, positively regulates the transcript level of MIF, and increased MIF results in exaggerated pulmonary expression of TLR-4, leading to the development of ALI with a subsequent infectious attack. We thus suggest that interventions designed to modulate MIF may have therapeutic advantages in treating ALI in patients with acute pancreatitis complicated by bacterial infection.

Serum elastase in the diagnosis of acute pancreatitis: a prospective study

BACKGROUND

The aim of the present study was to evaluate the usefulness of the elastase 1 (E1) enzyme-linked immunosorbent assay (ELISA) in the diagnosis of acute pancreatitis. This is the first Australian evaluation of the E1 ELISA.

METHODS

Three groups of patients were prospectively assessed: control patients, patients with acute pancreatitis, and patients with acute non-pancreatitic abdominal pain. Serum was collected on all patients on admission and the sensitivity, specificity and diagnostic accuracy of serum elastase, amylase and lipase was determined.

RESULTS

Twenty-nine patients with 30 episodes of pancreatitis, 38 patients with acute non-pancreatitic abdominal pain and 121 control patients were studied. For all patient episodes E1 ELISA at a cut-off of 3.5 ng/mL had a sensitivity of 80%, specificity of 96% and an efficiency of 94% in the diagnosis of acute pancreatitis. For episodes more than 48 h after onset of symptoms, sensitivity was 100%, specificity was 96% and diagnostic efficiency was 96%. This performance was equivalent to amylase but inferior to lipase.

CONCLUSION

Of the biochemical markers for pancreatitis currently available, lipase is the most useful. The relatively inferior sensitivity and problematic reference range for the ELISA E1, together with its limitations in measuring total elastase, currently prevent its widespread use.

Clinical laboratory assessment of acute pancreatitis

BACKGROUND

Several biochemical markers in blood and urine have been investigated to establish their clinical application in patients with acute pancreatitis (AP). The relevant studies are reviewed and critically appraised.

METHODS

Medline and the World Wide Web were searched and the relevant literature was classified under the following categories: (1) diagnosis of AP and (2) prediction of: a) disease severity, b) pancreatic necrosis and its secondary infection, c) organ failure and death, and d) disease etiology.

RESULTS AND CONCLUSIONS

Serum lipase is a more reliable diagnostic marker of AP than serum amylase. Urinary strip tests for trypsinogen activation peptide (TAP) and trypsinogen-2 provide a reliable early diagnosis of AP. Useful predictors of severity may include serum procalcitonin and urinary TAP and trypsinogen-2 on admission, serum interleukins-6 and -8 and polymorphonuclear elastase at 24 h, and serum C-reactive protein (CRP) at 48 h. Other markers such as amyloid A and carboxypeptidase B activation peptide (CAPAP) need further investigation. Biochemical prediction of pancreatic necrosis requires 72 h to reach reliability and is impractical. However, the daily monitoring of serum procalcitonin provides a non-invasive detection of infected necrosis; the promising role of phospholipase A(2) in this regard requires further investigation. Early transient hypertransaminasemia reliably predicts biliary etiology, while serum carbohydrate-deficient transferrin and trypsin may predict an alcoholic etiology.

Cutting edge: an endogenous pathway to systemic inflammatory response syndrome (SIRS)-like reactions through Toll-like receptor 4

Systemic inflammatory response syndrome (SIRS) is typically associated with trauma, surgery, or acute pancreatitis. SIRS resembles sepsis, triggered by exogenous macromolecules such as LPS acting on Toll-like receptors. What triggers SIRS in the absence of infection, however, is unknown. In this study, we report that a SIRS-like response can be induced in mice by administration of soluble heparan sulfate, a glycosaminoglycan associated with nucleated cells and extracellular matrices, and by elastase, which cleaves and releases heparan sulfate proteoglycans. The ability of heparan sulfate and elastase to induce SIRS depends on functional Toll-like receptor 4, because mutant mice lacking that receptor or its function do not respond. These results provide a molecular explanation for the initiation of SIRS.

Severe acute pancreatitis is related to increased early urinary levels of the activation Peptide of pancreatic phospholipase A(2)

BACKGROUND/AIM

In acute pancreatitis, it is believed that generalized activation of pancreatic zymogens leads to autodigestion of the pancreas and if excessive to systemic organ injury. Under physiological circumstances, secretory phospholipase A(2) type I (sPLA(2)-I) is activated by trypsinogen, but the extent of this activation in acute pancreatitis is unclear. The aim of this study was to assess time course and level of activation of sPLA(2)-I and trypsinogen in acute pancreatitis, relative to severity.

METHODS

246 patients were enrolled into a prospective European multicenter study. 137 patients had mild and 35 had severe acute pancreatitis, and there were 74 control patients. Urinary samples were taken on admission and at 6-hour intervals for 48 h, then every 12 h up to 72 h, and finally daily for at least 5 days for measurement of the activation peptide of sPLA(2)-I (pro-phosphatase A(2); PROP) and trypsinogen activation peptide.

RESULTS

The median maximum PROP values were significantly elevated 48 h after symptom onset in patients with severe acute pancreatitis [1.52 (95% CI 0.8-2.9) nmol/l] as compared with patients with mild acute pancreatitis [0.72 (0.55-1) nmol/l, p = 0.002] and controls [0.49 (0.22-1.2) nmol/l, p = 0.001], but not before or after this time point. The best cutoff point for urinary PROP to predict overall severity was >1 nmol/l < or =48 h after symptom onset (negative predictive value = 88%), but the PROP levels failed to predict the development of multi-organ dysfunction.

CONCLUSIONS

Activation of sPLA(2)-I is associated with the early pathogenesis of acute pancreatitis, but not in the development of distant organ damage. This observation raises questions as to the theory of generalized zymogen activation being a principle mechanism involved in the pathogenesis of distant organ damage in acute pancreatitis.

New laboratory tests in acute pancreatitis

Acute pancreatitis (AP) is a common disease with wide variation of severity. The diagnosis of AP is usually based on high serum amylase or lipase values but the accuracy of these methods is considered unsatisfactory. One in five of the patients develops a severe disease and carries a considerable risk of development of organ failure and high mortality. Early detection of patients with severe AP and especially those with increased risk of organ failure is importance since such patients seem to benefit from treatment in an intensive care unit started as soon as possible after presentation. In addition to enzymological methods, increasing interest has been focused on laboratory markers reflecting the level of inflammatory response in AP. At present, in routine clinical work the most commonly used severity marker is serum C-reactive protein, the concentration of which rises too slowly to be used for early prediction of severity. New therapies aiming at modifying the course of systemic inflammation in AP are being developed and therefore monitoring the patient's immune inflammatory status is needed. In this review article we present the current knowledge of laboratory tests, which has been evaluated for diagnostic and prognostic purposes in AP.