Fecal elastase-1 as a test for pancreatic function: a review.

Pancreatic elastase-1 is a specific human protease synthetized by the acinar cells. Immunoreactive elastase-1 cannot be detected in either porcine or bovine pancreatic enzyme preparations. It is very stable and, in contrast to fecal chymotrypsin, elastase is unaffected by exogenous pancreatic enzyme treatment, and correlates well with exocrine pancreatic function tests. The measurement of this proteolytic enzyme in stool by means of an enzyme-linked immunosorbent assay (ELISA) is a sensitive, specific, and relatively inexpensive non-invasive test. It is an accurate function test for patients with chronic pancreatitis confirmed by endoscopic retrograde cholangiopancreatography and computerized axial tomography. It shows higher sensitivity and specificity for exocrine pancreatic insufficiency than fecal chymotrypsin determination and is comparable to oral pancreatic function tests such as the pancreolauryl test.     

Hereditary pancreatitis in a young adult: Acute to chronic

This report investigates an unusual case of recurrent pancreatitis. A 22-year-old female was admitted to the emergency room for severe abdominal pain, nausea, and weight loss. She reported having these symptoms since she was a toddler. The clinician ordered fecal pancreatic elastase-1, fat-soluble vitamins, molecular studies, and imaging of the pancreas by computed tomography. The screening test result for fecal pancreatic elastase-1 revealed severe pancreatic exocrine insufficiency, and the concentrations of fat-soluble vitamins were also low. Imaging showed scattered calcifications in the pancreas. These findings supported a diagnosis of chronic pancreatitis. Due to the rarity of chronic pancreatitis in young adults, molecular studies were performed. The patient was found to be homozygous for a mutation in the SPINK1 gene, which is associated with hereditary pancreatitis. This case report discusses hereditary pancreatitis and highlights data on the utilization of fecal pancreatic elastase-1 to assess pancreatic exocrine insufficiency.     

Fecal chymotrypsin and elastase-1 determination on one single stool collected at random: diagnostic value for exocrine pancreatic status

OBJECTIVE: The secretin-cholecystokinin test is the "gold standard" to evaluate exocrine pancreatic function. But this direct duodenal intubation test is invasive, particularly in children, time-consuming, and expensive. For several years, indirect noninvasive tests of pancreatic insufficiency have been developed, such as fecal chymotrypsin (FChT) and fecal elastase-1 (FEL-1) measurements. Generally, elastase-1 is truly admitted to be the most relevant test of exocrine pancreatic status. However, so far, no consensus for stool collection protocol exists. The aim of our study was to investigate the diagnostic advantage from measuring fecal proteases in stool samples collected for two or three consecutive days in comparison to one single stool sample collected at random. DESIGN: A total of 69 children were divided into group A (stool samples collected for three consecutive days) and group B (stool samples collected for two consecutive days). These two groups included pancreatic-sufficient patients (PS) and severe pancreatic-insufficient patients (PI). One single determination of fecal chymotrypsin activity and of fecal elastase-1 concentration was realized on each stool. RESULTS: The same relatively important intraindividual variability of fecal proteases was observed in group A and B (mean coefficients of variation (CVs) 36% vs. 40.2% for chymotrypsin, 22.2% vs. 26.8% for elastase-1). No significant PS or severe PI diagnostic discordance was observed between 1, 2, or 3 days of stool collections. CONCLUSION: Our study clearly shows that the determination of fecal proteases on one single stool collected at random is sufficient to evaluate pancreatic exocrine status for PS and severe PI.     

Diagnostic utility of a new monoclonal antibody pancreatic isoamylase assay in chronic pancreatic diseases

In order to evaluate the efficacy of a monoclonal pancreatic (P) isoamylase assay in the diagnosis of chronic pancreatic disease and to compare the behavior of this test with that of amylase and elastase 1, these three enzymes were measured in the sera of 39 healthy controls, 28 patients with pancreatic cancer, 50 with chronic pancreatitis and 60 with extra-pancreatic diseases. In patients with chronic relapsing pancreatitis, increased P-isoamylase and elastase 1 values were found in similar percentages (about 70%), whereas the percentage for elevated amylase values was lower (52%). Elastase 1 was increased in 52% of patients with pancreatic cancer, while the other two enzymes were only occasionally elevated. The levels for all three enzymes were abnormal in some patients with extra-pancreatic diseases. It may be concluded that this assay for P-isoamylase determination is sufficiently sensitive and reliable in detecting pancreatic inflammation, even though some limitations concerning its specificity should be born in mind.     

Comparative evaluation of the diagnosis of acute pancreatitis based on serum and urine enzyme assays

We compared the diagnostic sensitivities of serum amylase, lipase (assayed enzymatically and immunologically), trypsinogen and elastase-1, the 2-h-timed urine amylase excretion and the ratio of amylase and creatinine clearances in the recognition of acute pancreatitis. Serial serum and urine findings from 39 patients with acute pancreatitis, and from 42 patients with non-pancreatic causes of abdominal pain (controls), as well as findings from 24 healthy subjects (normals) were studied. Decision thresholds were established for each parameter using either the control or the normal population, and the resulting diagnostic sensitivities determined. On hospital admission, all serum assays were equally sensitive, but on subsequent days lipase, trypsinogen and elastase-1 assays all significantly surpassed the sensitivity of the serum amylase assay. On the second and subsequent hospitalization days, determination of timed urine amylase excretion offered no advantage over the serum amylase, and the ratio of amylase and creatinine clearances lacked discrimination altogether.     

Evaluation and comparison of cathodic trypsin-like immunoreactivity, pancreatic lipase and pancreatic isoamylase in the diagnosis of acute pancreatitis in 849 consecutive patients with acute abdominal pain

In 849 patients (417 men, 432 women) consecutively hospitalized with acute abdominal pain we compared the value of serum cathodic trypsin-like immunoreactivity, pancreatic lipase (EC 3.2.1.3) and pancreatic isoamylase (EC 3.2.1.1) as diagnostic tests for acute pancreatitis. The diagnoses of acute pancreatitis (in 49 patients, 5.8%) and other diseases were made without knowledge of these enzyme values. When evaluated by means of receiver operating characteristic curves no differences were found in diagnostic performance of the three enzymes. Use of combinations of different enzymes had no advantage over single enzyme determination using discrimination analysis for evaluation. The highest efficiency was for all three enzymes 0.991 (95% confidence limits: 0.983-0.995) and for all three enzymes the discrimination value giving this efficiency was several times the upper limit of reference range: 1 779 micrograms/l for cathodic trypsin-like immunoreactivity, 831 U/l for pancreatic isoamylase and 316 micrograms/l for pancreatic lipase. None of the enzymes had any prognostic value at admission in predicting a mild or severe attack of acute pancreatitis. In conclusion, no single enzyme or combination of enzymes had any diagnostic advantage for acute pancreatitis in patients with acute abdominal pain. Thus selection of one of the three enzymes as diagnostic test of acute pancreatitis is to be based on considerations such as economy, methodological simplicity, possibility of automated assay and the time-consumption at the assay.     

Serum phospholipase A2 activity in chronic pancreatic diseases.

This study was performed to investigate the phospholipase A2 (PLA2) serum activity in patients with chronic pancreatic disease. PLA2, elastase-1, total, and pancreatic isoamylase were evaluated in 40 control subjects, 28 patients with pancreatic cancer, 51 with chronic pancreatitis, and 36 with extrapancreatic diseases, mainly of gastrointestinal origin. Elastase-1, PLA2, and pancreatic isoamylase were increased in 56%, 25%, and 15% of patients with pancreatic cancer, and in 40%, 31%, and 41% of subjects with chronic pancreatitis. All four enzymes gave pathological values in a number of patients with extrapancreatic diseases. We conclude that the diagnostic efficacy of phospholipase A2 in chronic pancreatic disease is similar to that of other well known pancreatic enzymes, with an unsatisfactory sensitivity and specificity.     

Evaluation of a new urinary amylase test strip in the diagnosis of acute pancreatitis

We have developed a novel rapid test strip for detecting pancreatic amylase in urine and prospectively evaluated its accuracy in screening for acute pancreatitis (AP). The test strip is based on the immunochromatography principle and uses two monoclonal antibodies specific for pancreatic amylase. Urine samples were collected from 500 consecutive patients with acute abdominal disease (52 with AP) and prospectively tested with the strip. The accuracy of the test strip was compared with that of two quantitative urine amylase determinations and a urinary dipstick test for amylase (Rapignost). Sensitivity of the test was 69% and specificity was 97% in differentiating patients with AP from those with acute abdominal extrapancreatic disease at admission. The negative predictive value was 0.986. The test showed moderate agreement both with an assay measuring total amylase activity and with another measuring pancreatic amylase immunoreactivity. At similar high specificity (97%), quantitative determination of total amylase activity (cut-off 3960 U/L) and pancreatic amylase (cut-off 2180 micrograms/L) showed lower sensitivity (54% and 41%) than the test strip (69%). The test is specific and rapid to perform, and it rules out AP with high probability. It could therefore be useful in an emergency setting without laboratory facilities in the differential diagnosis of acute abdominal pain.     

Advances in the enzyme diagnosis of pancreatic diseases

This paper reviews recent developments of analytical methods for the determination of alpha-amylase, of its isoenzymes, and of lipase. The evaluation of severity and etiology of acute pancreatitis by enzyme assays, e.g., pancreatic elastase 1, phospholipase A2, and routine enzymes are discussed. The limited significance of enzyme determinations as compared to imaging and endoscopic procedures for the diagnosis of chronic pancreatitis is demonstrated. Indirect "tubeless" tests for the evaluation of pancreatic exocrine insufficiency with respect to the secretion of chymotrypsin (chymotrypsin in stool and NBT-PABA test) and cholesterol esterase (pancreolauryl test) are reviewed. Finally, the superiority of morphologic investigations over biochemical tests for the timely detection of pancreatic carcinoma is shown.     

Stem cell factor and macrophage-colony stimulating factor in patients with pancreatic cancer.

Stem cell factor (SCF) and macrophage-colony stimulating factor (M-CSF) have assumed an increasing importance in cancer biology. In the present study we investigated the serum levels of these cytokines in pancreatic cancer patients in relation to controls and to patients with benign lesions of the pancreas (chronic pancreatitis group). The classical tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9) were also tested. We compared the serum levels of cytokines with tumor stage. We also defined the receiver-operating characteristics (ROC) curve for cytokines and classical tumor markers. The cytokines were measured in 47 patients with pancreatic cancer, in 27 patients with chronic pancreatitis and in 35 healthy subjects. SCF and M-CSF were determined using enzyme-linked immunosorbent assay (ELISA). CEA and CA 19-9 were measured by microparticle enzyme immunoassay. There were significant differences in the levels of circulating SCF, M-CSF, CEA and CA 19-9 in the pancreatic cancer patients compared to the control group, but only the serum levels of M-CSF, CEA and CA 19-9 were significantly higher in pancreatic cancer patients compared to the pancreatitis group. The levels of cytokines and tumor markers were higher in patients with a more advanced tumor stage. The M-CSF serum levels correlated positively with the tested tumor markers. The M-CSF area under the ROC curve was higher than the SCF area. These results suggest that M-CSF is a better candidate for a pancreatic cancer tumor marker than SCF.     

Evaluation of a fecal pancreatic elastase-1 enzyme-linked immunosorbent assay: Assessment versus an established assay and implication in classifying pancreatic function

BACKGROUND: Disagreement continues regarding 2 fecal pancreatic elastase-1 (PE-1) ELISAs and their respective capabilities to assess pancreatic function. METHODS: The BioServ Diagnostics polyclonal PE-1 ELISA was validated and its performance characteristics compared to the previously validated ScheBo((R)) Biotech monoclonal PE-1 ELISA. Split sample study results were analyzed by Deming regression and Bland-Altman plot analysis. Data mining was utilized to explore PE-1 distribution and evaluate PE-1 and fecal fat correlation. RESULTS: Analysis demonstrates limited quantitative agreement; slope=0.9640, intercept=10.787, R(2)=0.633. Means were 228.8 and 226.2 microg PE-1/g stool for the polyclonal and monoclonal assays respectively. Bland-Altman analysis showed 91% of paired values within 2 SD of their means. There was good qualitative agreement when interpreted against established intervals with 91% of results equivalent in pancreatic function classification. The remaining 9% varied by one classification level with no bias evident. The distribution of PE-1 concentrations (n=400, 0-25 years) classified 78% of subjects with normal pancreatic function, 7% with moderate pancreatic insufficiency and 15% with severe insufficiency. There was little agreement between PE-1 and fecal fat results. CONCLUSIONS: The polyclonal PE-1 ELISA is an acceptable alternative to the monoclonal PE-1 ELISA. PE-1 is a potential substitute for fecal fat for evaluating pancreatic function.     

Endosonographic features in patients with non-alcoholic early chronic pancreatitis improved with treatment at one year follow up

Since the prevention of early chronic pancreatitis (ECP) into chronic pancreatitis might be critical for the reduction of pancreatic cancer, we tried to clarify the pathophysiology of ECP patients, focusing on ECP patients without alcoholic chronic pancreatitis. 27 ECP patients without alcoholic chronic pancreatitis and 33 patients with functional dyspepsia with pancreatic enzyme abnormalities (FD-P) were enrolled in this study. Diagnosis of ECP was made when imaging findings showed the presence of more than 2 out of 7 endoscopic ultrasound features. Duodenal degranulated eosinophils and glucagon-like peptide 1 producing cells were estimated by immunostaining. There were no significant differences in characteristics and psychogenic factors between ECP and FD-P patients. Interestingly, endoscopic ultrasound score in ECP patients significantly improved, albeit clinical symptoms in ECP patients showed no improvement at one year follow up. The extent of migration of duodenal degranulated eosinophils in FD-P patients was significantly higher compared to that in ECP patients. The levels of elastase-1 and trypsin in ECP patients with improved endoscopic ultrasound features were significantly reduced by the treatment. Further studies will be needed to clarify whether clinical symptoms and endoscopic ultrasound features in ECP patients without alcoholic chronic pancreatitis were improved in longer follow up study.     

Immunochemical qualitative latex agglutination test for pancreatic lipase in serum evaluated for use in diagnosis of acute pancreatitis

In 417 patients (213 men, 204 women) consecutively hospitalized with acute abdominal pain we evaluated the clinical usefulness of a latex-agglutination test at admission to screen for concentrations of pancreatic lipase (EC 3.1.1.3) in serum greater than 300 micrograms/L. The diagnoses of acute pancreatitis (in 25 patients, 6%) and other diseases were made without knowledge of the results of the latex test or of quantification of pancreatic lipase in the serum by enzyme immunoassay. In the latex assay, when agglutination was taken as a positive test for acute pancreatitis, we found a diagnostic efficiency of 0.986 (95% confidence limits: 0.971-0.997) for acute pancreatitis. The predictive value of a positive latex test result with respect to acute pancreatitis was 0.807 (0.625-0.926); the predictive value of a negative test was 1.000 (0.991-1.000). Six patients had false-positive test results. No false-negative test results were found by enzyme immunoassay. We conclude that the latex agglutination test is useful as an emergency test for diagnosis of acute pancreatitis in patients with acute abdominal pain; negative results virtually exclude acute pancreatitis.     

Endoscopic ultrasonography (EUS) and fine-needle aspiration (FNA) cytology for diagnosis of chronic pancreatitis

BACKGROUND AND STUDY AIMS: Previous studies have shown that endoscopic ultrasonography (EUS) sensitively detects morphologic abnormalities due to chronic pancreatitis. However, morphologic EUS findings have limited specificity, particularly at the early stages of chronic pancreatitis. Our aims were to study pancreatic morphology and inflammation in patients with chronic pancreatitis, using EUS and fine-needle aspiration cytology (EUS-FNA), and to compare the results with those of endoscopic retrograde cholangiopancreatography (ERCP) and pancreatic function tests. PATIENTS AND METHODS: 37 patients (48 +/- 13 years) with clinical symptoms and laboratory test findings suggestive of chronic pancreatitis were prospectively studied. Patients with malignancy or major concomitant disorders were excluded. Clinical evaluation included indirect pancreatic function tests. Morphologic criteria for chronic pancreatitis included echo-intense septae/echo-reduced foci (i. e. pseudolobularity), ductal irregularities, and calcifications. EUS-FNA was performed in 27/37 patients, by means of the Hitachi FG34-UX echo endoscope and a 22-gauge needle, and tissue specimens were submitted for standard cytological evaluation. ERCP served as reference in all patients, using the Cambridge classification. RESULTS: 31 patients had chronic pancreatitis while six had normal findings at ERCP. EUS showed morphologic abnormalities of the pancreas in 33 patients. Morphologic abnormalities alone reached a sensitivity of 97 % for chronic pancreatitis with a specificity of only 60 %, while the positive predictive value (PPV) was 94 %, and the negative predictive value (NPV) was 75 %. EUS-FNA increased the negative predictive value to 100 % and the specificity to 67 %. On average, 2.3 needle passes were necessary to obtain sufficient amounts of tissue. The correlation of EUS findings with pancreatic function tests was poor. EUS results were in agreement with regard to the severity of chronic pancreatitis in 5/8 patients with grade I disease, in 11/13 patients with grade II, and in 10/10 patients with grade III disease. Minor complications occurred in two patients (7 %). CONCLUSIONS: EUS is as sensitive and effective as ERCP in the detection of chronic pancreatitis, particularly when only mild disease is present. However, EUS findings have limited specificity, particularly in patients with mild disease. EUS-FNA with cytology is safe and improves the negative predictive value. Negative EUS-FNA findings rule out chronic pancreatitis, but cytological investigation alone does not improve the specificity of EUS findings, suggesting that further improvements in tissue sampling and analysis are necessary to support routine use of FNA in patients with chronic pancreatitis.     

Clinical course of alcoholic pancreatitis

AIM: To study a natural course of alcoholic pancreatitis (AP). MATERIAL AND METHODS: Follow-up clinical, laboratory and radiation examinations were made of 170 patients with alcoholic pancreatitis. Exocrine secretion of the pancreas was assessed by secretin-pancreozymin test. Morphological signs of pancreatitis were studied in patients who had died of pancreatic cancer. RESULTS: In 24% of patients AP manifested with acute attack. In 76% it was preceded with weak clinical symptoms. AP ran was complicated with pseudotumorous pancreatitis, calcinosis and pancreatic pseudocysts. Pancreatic secretion was suppressed in 87% patients though clinically it was evident only in 12% cases. Autopsy cases of pancreatic cancer carried morphological markers of chronic pancreatitis. CONCLUSION: Various clinical forms of AP represent stages of its development: early symptoms, recurrences, complications and decompensated failure of the pancreatic function. The presence of pancreatitis in patients with pancreatic cancer causes difficulties in differential diagnosis between these diseases.     

胰型淀粉酶、脂肪酶在急性胰腺炎中的临床应用

目的为了评价急性胰腺炎中胰型淀粉酶（P—AMY）的临床应用价值,对总淀粉酶（α-AMY）、P—AMY、脂肪酶（lipase,LPS）进行方法学评价。方法选择急性胰腺炎患者126例、其他疾病患者对照组105例、健康对照组95例,用日立7600全自动生化分析仪测定α-AMY、P—AMY、LPS。本实验室临界值定为α-AMY216 U／L、P—AMY 115U／L、LPS 200U／L。结果α-AMY、P-AMY、LPS灵敏度分别为73．1％、88．5％、92．3％,特异性分别为70．5％、81．9％、82．9％,ROC工作曲线下α-AMY、P-AMY、LPS灵敏度分别为65．4％、88．5％、88．5％,特异性分别为86．7％、80．9％、89．5％,α-AMY和P—AMY之间差异有统计学意义（P=0．045）,P-AMY和LPS之间差异无统计学意义（P=0．613）。结论P-AMY检测比α-AMY更敏感、更特异性地反映急性胰腺炎。LPS也同样在急性胰腺炎中具有高灵敏度和特异性,临床上应同时检测P-AMY和LPS作为诊断急性胰腺炎的指标,具有更重要意义。     

SHCS and the laboratory diagnosis of HIV infection--from the development of the HIV Western blot to virus quantification and clinically relevant individual virus characterization

The first reliable diagnostic tools for the diagnosis of HIV infection, Western blot and ELISA, were created 20 years ago in the U.S., using initially sera from AIDS patients diagnosed clinically in Switzerland. In Swiss laboratories the diagnosis of HIV infection today is established by using 4th generation screening tests which detect both antibodies and p24 antigen while in the doctor's surgery a rapid antibody assay is used. Confirmation in authorized confirmatory labs relies on a set of different minimal combinations of positive test results derived from both the first and second blood specimen. In patients with a confirmed diagnosis of HIV infection, two further principal questions arise concerning, on the one hand, the virus load and, on the other hand, some clinically relevant properties of the infecting virus (type or subtype, resistance against antiretroviral drugs). The paper starts with a personal flashback to the first days of HIV diagnostics and describes the sensible use of tests available today for answering the above-mentioned principal questions. Alternative methods which can be used when standard tests fail or appear unreliable are mentioned also.     

血清黏蛋白抗原4对胰腺癌的诊断价值研究

摘要：目的：研究血清黏蛋白抗原4(mucin antigen 4,MUC4)对胰腺癌诊断价值。 方法：用ELISA法测定胰腺癌患者血清中MUC4的含量,根据ROC曲线确定MUC4的cut off值并计算ROC曲线下面积（AUC^ROC）,根据诊断效能评估表评价MUC4、CA19-9和CA242对胰腺癌诊断价值。 结果:胰腺癌患者血清MUC4的浓度和阳性率与慢性胰腺炎组及健康对照组比较有显著性差异(P<0.01),而慢性胰腺炎组与健康对照组之间无明显差异(P>0.05);MUC4的cut off值为4.54 ng/mL,AUC^ROC为0.880;胰腺癌患者血清MUC4表达敏感性、特异性和准确性明显优于CA19-9和CA242（P<0.01）。 结论:MUC4可单独或与其他指标联合应用诊断胰腺癌,作为鉴别胰腺癌和慢性胰腺炎的重要参考指标。     

Evaluation of a dipstick method for the detection of human immunodeficiency virus infection

Serology has been a fundamental tool to prevent post-transfusional infection with human immunodeficiency virus (HIV) and for epidemiological surveys, the first step to attempt control of the pandemia. Enzyme immunoassay is in widespread use. Nevertheless, simpler methods are needed in many countries, where laboratory facilities and trained personnel are limited, and HIV prevalence is high. The evaluation of a simple and noninstrumented HIV antibody test is presented here. The test employs synthetic antigens of HIV-1 and HIV-2 attached to the teeth of a polystyrene comb, which fit into the wells of standard microtiter plates where samples are diluted. Captured antibodies are developed with colloidal gold-labeled Protein A. Three seroconversion panels plus 662 samples were tested, including HIV-1 and HIV-2-infected individuals, normal blood donors, and a noninfected baby born to a seroreactive mother. When compared with enzyme-linked immunosorbent assay (ELISA) and Western blot, the dipstick showed 100% sensitivity and 98.7% specificity. The simplicity of result evaluations and excellent reagent stability make the dipstick suitable for small blood banks and for epidemiological surveys.