Evaluation of the clinical usefulness of pancreatic alpha amylase as a novel biomarker in dogs with acute pancreatitis: a pilot study

Pancreatic alpha amylase (P-AMY) is used as a biomarker of acute pancreatitis (AP) in human medicine. To our knowledge, there are no studies evaluating the usefulness of P-AMY in dogs with AP. In this study, we evaluated the diagnostic value of P-AMY, currently not verified in veterinary medicine. The AP group (n = 40) consisted of dogs with AP diagnosed using clinical signs and laboratory examinations, including abnormal canine pancreatic lipase (cPL) concentration, and compatible abdominal ultrasound examination at first presentation. Evaluation of the canine AP severity (CAPS) score was performed. The control group (n = 38) was composed of normal dogs without any abnormalities in clinical findings, blood exams or diagnostic imaging. The correlation of P-AMY with cPL was confirmed by Pearson's correlation analysis (r = 0.564, p < .001). The sensitivity and specificity for the most appropriate cut-off values of P-AMY were recorded similar to the values of DGGR. The dogs with AP and CAPS ≥11 had significantly higher serum P-AMY (p = .016) contrary to DGGR lipase and cPL. Furthermore, there was a significant difference in the median P-AMY dependent on the presence of systemic inflammatory response syndrome (p = .001). P-AMY showed similar level of diagnostic accuracy along with sensitivity and specificity compared to DGGR lipase. In addition, P-AMY showed a significant association with CAPS score, contrary to cPL and DGGR lipase. Along with other biomarkers associated with AP, P-AMY has the potential of usefulness as a supportive diagnostic and prognostic biomarker of AP in dogs.

Type of CFTR mutation determines risk of pancreatitis in patients with cystic fibrosis

BACKGROUND & AIMS

Different mutations in the cystic fibrosis gene (CFTR) are associated with different functional status of the exocrine pancreas. We investigated whether CFTR genotypes determine the risk of pancreatitis in patients with cystic fibrosis (CF).

METHODS

Patients with pancreatic-sufficient CF were identified from 2 CF population-based databases (N = 277; 62 with pancreatitis and 215 without pancreatitis); patients' genotypes and clinical characteristics were analyzed. The loss of pancreatic function associated with each CFTR genotype was determined based on the pancreatic insufficiency prevalence (PIP) score.

RESULTS

Patients with pancreatitis were more likely to have genotypes associated with mild (70%) than moderate-severe (30%) PIP scores (P = .004). The cumulative proportion of patients who developed pancreatitis through to the age of 50 years was significantly greater for genotypes associated with mild (50%) than moderate-severe (27%) PIP scores (P = .006). The genotype associated with mild PIP scores had a hazard ratio of 2.4 for pancreatitis (95% confidence interval, 1.3-4.5; P = .006). Patients with pancreatitis were diagnosed with CF at an older median age than those without pancreatitis (14.9 years [interquartile range, 9.5-27.7] vs 9.3 years [interquartile range, 1.5-21.4]; P = .003) and had lower mean levels of sweat chloride than patients without pancreatitis (74.5 ± 26.2 mmol/L vs 82.8 ± 25.2 mmol/L; P = .03).

CONCLUSIONS

Specific CFTR genotypes are significantly associated with pancreatitis. Patients with genotypes associated with mild phenotypic effects have a greater risk of developing pancreatitis than patients with genotypes associated with moderate-severe phenotypes. This observation provides further insight into the complex pathogenesis of pancreatitis.

Evidence of a generalized defect of acinar cell function in Shwachman-Diamond syndrome

BACKGROUND

: Because the acinar cells of the exocrine pancreas in patients with Shwachman-Diamond syndrome (SDS) are severely depleted, we hypothesized that a similar deficiency may be present in acinar cells of the parotid gland.

PATIENTS AND METHODS

: We determined serum pancreatic isoamylase and parotid amylase activities in 16 patients with SDS, 13 healthy controls, and 13 disease controls (cystic fibrosis or fibrosing pancreatitis). Parotid amylase and electrolyte concentrations were measured in stimulated parotid gland secretions. Starch digestion was assessed by breath hydrogen testing in patients with SDS (with and without enzyme supplements) and healthy controls.

RESULTS

: Serum pancreatic and parotid isoamylase values were lower in the patients with SDS than in the healthy controls (P < 0.0001 and P = 0.0002, respectively). Serum pancreatic isoamylase, but not parotid isoamylase, was significantly lower in the disease controls than in the healthy controls (P < 0.0001 and P = 0.17, respectively). Secreted parotid gland amylase concentration (units per milligram of protein) in patients with SDS was lower than that in the healthy controls (P = 0.04), whereas the disease controls were comparable to the healthy subjects (P = 0.09). Secreted parotid chloride concentration was inversely correlated with amylase concentration in the patients with SDS (P = 0.01), but no correlation was seen in the healthy controls or disease controls. When patients with SDS ingested starch without enzyme supplementation, their breath hydrogen excretion was significantly higher than that in the healthy controls (P = 0.009). Following starch ingestion with enzymes, breath hydrogen in the patients with SDS was lower (P < 0.05) than with no enzyme treatment, and no different from controls (P = 0.37).

CONCLUSIONS

: Mutations in the SBDS gene cause a generalized functional abnormality of exocrine acinar cells.

Do common in silico tools predict the clinical consequences of amino-acid substitutions in the CFTR gene?

Computational methods are used to predict the molecular consequences of amino-acid substitutions on the basis of evolutionary conservation or protein structure, but their utility in clinical diagnosis or prediction of disease outcome has not been well validated. We evaluated three popular computer programs, namely, PANTHER, SIFT and PolyPhen, by comparing the predicted clinical outcomes for a group of known CFTR missense mutations against the diagnosis of cystic fibrosis (CF) and clinical manifestations in cohorts of subjects with CF-disease and CFTR-related disorders carrying these mutations. Owing to poor specificity, none of tools reliably distinguished between individual mutations that confer CF disease from mutations found in subjects with a CFTR-related disorder or no disease. Prediction scores for CFTR mutations derived from PANTHER showed a significant overall statistical correlation with the spectrum of disease severity associated with mutations in the CFTR gene. In contrast, PolyPhen- and SIFT-derived scores only showed significant differences between CF-causing and non-CF variants. Current computational methods are not recommended for establishing or excluding a CF diagnosis, notably as a newborn screening strategy or in patients with equivocal test results.

A case of a composite adrenal medullary tumor of pheochromocytoma and ganglioneuroma masquerading as acute pancreatitis

Composite adrenal medullary tumors, composed of both pheochromocytoma and ganglioneuroma, are extremely rare, as are pheochromocytomas masquerading as acute relapsing pancreatitis. We recently experienced a case of a 48-year-old male with both these phenomena. The patient complained of an acute onset of intense abdominal discomfort. At the same time, pancreatic enzymes were increased in concentration. An abdominal computed tomographic scan revealed an enlarged pancreas and a 3-cm left adrenal incidentaloma. Biochemical and 131I-MIBG scintigraphic findings were compatible with a pheochromocytoma. Yet, he had no clinical manifestations suggesting pheochromocytoma. An adrenalectomy was performed and a composite adrenal medullary tumor of pheochromocytoma and ganglioneuroma was confirmed during a pathologic examination. This case illustrates two points: 1) acute abdominal intense discomfort and hyperamylasemia may be unusual presentations of pheochromocytomas; and 2) the possibility of the pheochromocytoma, albeit rare, should be considered when a relapsing pancreatitis of uncertain etiology develops.

Lipase and pancreatic amylase versus total amylase as biomarkers of pancreatitis: an analytical investigation

OBJECTIVE

To evaluate the biomarkers of pancreatitis Colorimetric Lipase, Total Amylase and Pancreatic Amylase (immunoinhibition) assays on the Roche COBAS INTEGRA 700.

RESULTS

Pancreatic and Total Amylase assays and Colorimetric Lipase showed excellent imprecision of 1.6 to 2.3% and linearity (slope = 0.94-0.99, y-intercepts-1 to +3 U/L, r = 0.999) over the range of 17 to 900, 35 to 880, and 21 to 150 U/L, respectively. There was an excellent correlation between Pancreatic and Total Amylase: Pancreatic Amylase = 0.99 (+/- 0.02) x Total Amylase-36(+/- 8) (n = 106, r = 0.97, p < 1 x 10(-5), y intercept p < 1 x 10(-5)). Colorimetric Lipase showed some correlation to Total and Pancreatic Amylase results: Colorimetric Lipase = 1.54 (+/- 0.16) x Total Amylase-81(+/- 37) (n = 100, r = 0.70, p < 1 x 10(-6), y intercept p = 0.03), and Colorimetric Lipase = 1.78 (+/- 0.15) x Pancreatic Amylase-50(+/- 29) (n = 99, r = 0.78, p < 1 x 10(-6), y intercept p = 0.09).

CONCLUSION

We recommend running the more specific Pancreatic Amylase as biomarker of pancreatitis on the Roche COBAS INTEGRA.

Serum pancreatic enzymes define the pancreatic phenotype in patients with Shwachman-Diamond syndrome

OBJECTIVE

To evaluate the role of serum enzymes for defining the pancreatic phenotype in Shwachman-Diamond syndrome (SDS), an inherited multisystem condition.

STUDY DESIGN

Serum pancreatic trypsinogen and isoamylase were measured in 164 patients known or presumed to have SDS. The diagnosis was confirmed in 90 patients. Among 74 unconfirmed cases, 35 ("probable SDS") had hematologic dysfunction but lacked documented pancreatic dysfunction, whereas 39 patients ("improbable SDS") lacked both documented pancreatic and hematologic dysfunction. Classification and regression tree (CART) analysis was performed in 90 patients with SDS and 134 control patients to establish a rule for defining the pancreatic phenotype of SDS; the rule was then applied to the patients with unconfirmed diagnosis.

RESULTS

In the control patients, serum trypsinogen showed little variation with age, whereas serum isoamylase values rose from birth on, attaining adult values by 3 years. For patients with SDS, serum trypsinogen values were low in young patients and tended to increase with age, whereas serum isoamylase values remained low at all ages. The CART rule combined results from both enzymes and classified the pancreatic phenotype in all but one SDS patient, who was <3 years of age. Excluding patients <3 years of age, CART identified the pancreatic phenotype in 82% and 7% of the "probable SDS" and "improbable SDS" cases, respectively.

CONCLUSIONS

Serum pancreatic enzymes are useful for determining the pancreatic phenotype and confirming the diagnosis of SDS.

Recommendations for the routine use of pancreatic amylase measurement instead of total amylase for the diagnosis and monitoring of pancreatic pathology

This document reviews the scientific evidence expected to persuade clinical laboratories to substitute pancreatic amylase measurement for total amylase in cases of suspected pancreatic pathology. A substantial evidence is now available to support such change. The measurement of pancreatic amylase in serum is: 1. more sensitive and specific for the detection of pancreatic tissue damage than that of the total enzyme activity, 2. easy and quick to perform in emergency conditions, 3. analytically precise in relation to its clinical application, 4. suitable for easy transfer and comparison of results from different care delivery units, and 5. characterized by well-defined decision limits for the diagnosis of acute pancreatitis.

Development and evaluation of assays for the determination of total and pancreatic amylase at 37 degrees C according to the principle recommended by the IFCC

OBJECTIVES

The aim of our study was a) to optimize assays for measurement of total (T-) and pancreatic (P-)amylase at 37 degrees C based on the principle recommended by the IFCC at 30 degrees C, b) to evaluate the analytical performance of these assays in a multicentric study and c) to establish reference intervals for serum and urine for either method.

METHODS

Optimized conditions for 37 degrees C were elaborated with regard to substrate concentration, pH, inorganic additives and glucosidase activity. The cleavage pattern of the EPS substrate was studied by HPLC. Liquid ready-to-use reagents for T- and P-amylase were provided to six European laboratories.

RESULTS

The assays showed good performance characteristics (median intraassay CVs 1.0% for T- and 1.3% for P-amylase, median interassay CVs 3.0% for either assay, dynamic range 15-fold URL for T- and 30-fold for P-amylase), high correlation with the previous EPS methods (r > 0.996, slope 0.43, intercept < 5 U/L) in serum, heparin plasma and urine and good analytical specificity of the P-amylase assay (residual S-amylase activity 2.4%). Serum reference ranges were found to be 28 to 100 U/L for T- and 13 to 53 U/L for P-amylase (n = 775); URLs in urine were estimated as 490 U/L or 280 U/g creatinine for males and 450 U/L or 380 U/g creatinine for females with total amylase.

CONCLUSION

We believe that these assays based on the 30 degrees C IFCC recommendation represent a further improvement in amylase methodology at 37 degrees C and merit broad application in clinical routine.

Total and Pancreatic Amylase Measured with 2-Chloro-4-nitrophenyl-4-O-β-d-galactopyranosylmaltoside

Background: Many different methods have been used to assay amylase activity, using nitrophenylated oligosaccharides as substrate; however, the hydrolysis steps in these methods are complex.

Methods: We developed a new continuously monitoring assay for amylase activity in biological fluids, using 2-chloro-4-nitrophenyl-4-O-β-d-galactopyranosylmaltoside (GalG2CNP) as the substrate; this assay was used with anti-human salivary amylase monoclonal antibodies for specific determination of the pancreatic isoenzyme. Amylase converted GalG2CNP into β-d-galactopyranosylmaltose and 2-chloro-4-nitrophenol, which was measured at 405 nm.

Results: GalG2CNP was cleaved between 2-chloro-4-nitrophenol and β-d-galactopyranosylmaltose and did not undergo transfer reactions. The within-assay CVs (n = 20) for total amylase (T-AMY) and pancreatic amylase (P-AMY) were 0.6–1.6% and 0.5–2.5%, respectively; and day-to-day CVs (n = 10) for T-AMY and P-AMY were 0.8–3.7% and 0.6–4.1%, respectively. T-AMY and P-AMY activities in serum or urine obtained by the proposed method correlated well with those determined by the 2-chloro-4-nitrophenyl 4-O-β-d-galactopyranosyl-β-maltotetraoside method or the modified IFCC method.

Conclusions: This novel assay for T-AMY and P-AMY measures both activities stoichiometrically, directly, and easily, and may be suitable for routine procedures.

Determination of total and pancreatic alpha-amylase in human serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate

A reagent and assay conditions for the determination of the catalytic concentration of alpha-amylase (E.C. 3.2.1.1) in serum with 2-chloro-4-nitrophenyl-alpha-D-maltotrioside as substrate are described. The selected reaction mixture contains 50 mmol/l 2-(N-morpholino)ethanesulfonic acid buffer at pH 6.1 (37 degrees C), 300 mmol/l sodium chloride, 5 mmol/l calcium chloride and 450 mmol/l potassium thiocyanate. The described method is suitable for the measurement of total as well as pancreatic alpha-amylase by including antibodies against the salivary isoenzyme. The method shows the absence of a lag phase period, is sensitive and precise, has a large analytical range and is free from interference by hemoglobin, bilirubin and triglycerides. Comparative studies showed good correlation with other well established methods.

Analytical evaluation of a newly developed ELISA mass assay for pancreatic amylase

OBJECTIVE

To evaluate a newly developed ELISA mass assay for Pancreatic Amylase.

METHODS

The serum levels of pancreatic amylase were measured by an in-house developed ELISA assay on microtitre plate and compared with two activity assays: immunoinhibition and electrophoresis.

RESULTS

The proposed method was accurate and precise, as indicated by a recovery of 102% and coefficient of variation of less than 5% for within-run and less than 10% for between-run assay. The proposed assay showed good correlation with the activity assays (r = 0.98). The mass concentrations were three times higher than the activities. The relative values (mass or activity units/upper reference limits), however, were concordant in controls and in pancreatic and non-pancreatic conditions.

CONCLUSION

Our results indicate that the activity measurements and mass concentrations of pancreatic amylase in serum are comparable and interchangeable after adjusting for the reference range.

A new rapid immunoinhibition pancreatic amylase assay: diagnostic value for pancreatitis

A new rapid immunoinhibition pancreatic amylase assay was compared to total amylase and lipase in an unbiased sample of 1005 emergency department patients with suspicion of pancreatitis, of which 55 had a final diagnosis of pancreatitis. Imprecision of the assays for both amylases (less than 2.5%) were better than for lipase (less than 6.1%). Correlation (R2) of pancreatic amylase with total amylase was 0.991 but only 0.789 with lipase. Using Receiver Operator Characteristics analysis, the best diagnostic cutoff point for all three enzymes was near the upper limit of the reference interval. With pancreatic amylase, sensitivity, specificity, and predictive values for positive and negative results are, respectively, 85.5, 92.5, 39.8, and 99.1%; we found similar values for lipase but poorer values (78.2, 92.0, 36.1, and 98.7%) for total amylase. Tests combination did not improve the diagnostic performance significantly. In the diagnosis of pancreatitis, pancreatic amylase (p = 0.037) and lipase (p = 0.049) had better diagnostic performance than total amylase. The correct diagnosis of pancreatitis could be achieved in 47 instead of 43 patients with either pancreatic amylase or lipase as opposed to total amylase among 1005 patients in this study. We conclude that pancreatic amylase and lipase are incrementally better diagnostic tools than total amylase for the diagnosis of pancreatitis.

Renal isoamylase clearance as a measure of altered renal charge selectivity in patients with diabetes mellitus

Microalbuminuria is well established as a marker for early renal damage in diabetic patients. Differences in charge selectivity in glomerular protein filtration may also be an early marker of renal damage. We investigated the possible usefulness of the renal clearances of pancreatic and salivary amylases, and the ratio of the two, as markers of early renal damage in 55 diabetic subjects and 21 healthy controls. Diabetic patients with established albuminuria and microalbuminuria had increased clearance of salivary amylase and a trend toward lower pancreatic/salivary amylase clearance ratios compared to healthy controls and diabetic subjects without albuminuria, but the overlap with controls and diabetics without albuminuria was too large for the test to be useful.

Function tests in the diagnosis of chronic pancreatitis. Critical evaluation

Direct pancreatic function tests, such as the secretin-pancreozymin test and the Lundh test, are--by direct measurement of the contents of duodenal secretion following exogenous (hormonal) or endogenous (test meal) stimulation--the best way to assess exocrine pancreatic function. However, these tests are time-consuming, invasive, and expensive, and therefore their use is limited to specialized centers only. Several studies have shown that indirect pancreatic function tests are a practicable alternative to direct pancreatic function tests for diagnosing exocrine pancreatic insufficiency. They allow staging of the disease and thereby facilitate comparison of different studies. They are also useful in some cases for determining whether pancreatic enzyme replacement therapy is necessary or not. In contrast to morphological procedures, they involve neither side effects, risks for the patient, nor complications for patients, investigators, and laboratory staff alike. The procedures being standardized, the test results depend to a lesser extent on the experience of the investigator, and more on the selection of and the instructions to the patient, and to some extent, on the severity of the exocrine pancreatic insufficiency. Like all pancreatic function tests, the indirect tests do not give a clue to etiology nor help investigators to differentiate between pancreatic insufficiency owing to chronic pancreatitis and that owing to pancreatic cancer. The role of pancreatic function tests in diagnosing early chronic pancreatitis in comparison to morphological examinations remains to be established.

Parotid swelling. Does it affect serum isoamylase level?

Serum levels of total amylase and P-type, and S-type isoamylase were measured in 57 patients with chronic parotid swelling (41 men and 16 women; mean age 60.4) and the same number of age- and sex-matched control individuals without parotid swelling (41 men and 16 women; mean age 60.3). None of the three enzyme measurements differed significantly between patients with parotid swelling and control subjects. It is concluded that chronic enlargement of parotid glands does not affect serum isoamylase level.

Urinary phospholipase A2 excretion in chronic pancreatic diseases

This study was performed to investigate the behavior of phospholipase A2 (PLA2) in serum and urine of patients with chronic pancreatic diseases and to ascertain whether any factors influenced the results. In 30 controls, 45 patients with pancreatic cancer, 54 with chronic pancreatitis, and 64 with extrapancreatic diseases, serum and urinary PLA2, pancreatic isoamylase and RNase, and urinary N-acetylglucosaminidase (NAG) were measured. Serum PLA2 levels were higher in patients with chronic pancreatitis than in all the other groups. In our patients, only occasionally was urinary PLA2 elevated, the increase occurring almost exclusively in the presence of an acute inflammatory disease, e.g., relapsed chronic pancreatitis or active inflammatory bowel disease. A correlation was found between serum PLA2 and serum RNase, an indicator of tissue damage, but not between serum PLA2 and pancreatic isoamylase. Urinary PLA2 output was correlated with its renal input and with RNase output. No correlation was found between PLA2 output and pancreatic isoamylase or NAG urinary excretion. In conclusion, (1) the determination of serum PLA2 activity may be an aspecific test of pancreatic disease; (2) PLA2 urinary excretion occasionally increases, especially in the presence of severe phlogosis, which occurs in chronic pancreatitis, in particular during relapse; and (3) irrespective of the tissue origin of urinary PLA2, its increased excretion may be accounted for in part by its increased circulating levels. It is, however, more likely the consequence of a renal tubular dysfunction, which is sometimes found in patients with pancreatic diseases.

New method for the determination of pancreatic amylase evaluated

We have carried out a multicenter evaluation of a new reagent carrier for Reflotron, specific for pancreatic amylase where the salivary isoenzyme is inhibited by two specific monoclonal antibodies. This new procedure combines easy handling with low imprecision (median CV less than 3%) in control material, serum, heparinized blood, and plasma) and close correlation (r = 0.991 to 0.999) with established manual and automated methods. The same close correlation was found with values obtained from either venous or capillary finger-stick blood. Salivary amylase up to 54 kU/L (37 degrees C) was inhibited to about 97%. Endogenous interference by hemoglobin, bilirubin, triglycerides, cholesterol, or hematocrit was found to be negligible within a wide range of interferent concentrations. Out of a panel of 28 commonly used drugs it was shown that only two (ascorbic acid and paracetamol), and then only at toxic concentrations, caused a deviation in amylase activity of greater than 10%. From the results of this study we conclude that this new method is suitable for highly precise and accurate measurements of pancreatic amylase in emergency and routine laboratories.

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.

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.

Monoclonal antibodies to barley alpha-amylase I: production, characterization, and application to a specific immunoassay

Monoclonal antibodies (MAbs) to barley alpha-amylase I have been produced, purified and characterized. Six are specific for the alpha-amylase I isoform, while one also reacts with alpha-amylase II. All but one recognize the antigen in solution. Topology of the MAbs was investigated by additivity in ELISA, which led us to subdivide them into four groups. An immunoassay was developed using one of these MAbs, to measure alpha-amylase I activity in an extract containing both isoforms.

Diagnostic value of measuring pancreatic isoamylase with a double-monoclonal antibody immunoassay in serum of hospitalized hyperamylasemic patients

We evaluated the diagnostic utility of measuring pancreatic isoamylase (P-AMY) with a double-monoclonal antibody technique in a population of 43 consecutive hospitalized hyperamylasemic patients in comparison with serum pancreatic lipase (LPS) activity. In 27 cases (62.8%), the final diagnosis was acute pancreatitis. Predictive values were calculated for P-AMY and LPS activities, and a P-AMY percentage was calculated for selected decision levels. The maximal diagnostic efficiency was 0.930, 0.814, and 0.767 for LPS, P-AMY activity, and P-AMY percentage, respectively, indicating that serum LPS measurement was clinically superior to P-AMY for distinguishing patients with or without pancreatitis. Measurement of both P-AMY activity and percentage in serum did not significantly improve diagnostic accuracy.

Tumor-associated trypsin inhibitor in patients with chronic pancreatic diseases

Serum TATI (tumor-associated trypsin inhibitor) was measured in 41 control subjects, 30 patients with pancreatic cancer, 53 with chronic pancreatitis, and 47 with extrapancreatic diseases, mainly of gastrointestinal origin. TATI was found to be elevated in some subjects in all groups of patients; patients with chronic pancreatitis studied during an acute exacerbation of the disease had the highest percentage (68%) of pathological values. TATI was found to be correlated with elastase 1, tissue polypeptide antigen, and total and pancreatic isoamylase. A significant relationship was also found between TATI and serum creatinine levels.

Comparison of two methods for the determination of the isoenzymes of alpha-amylase in serum and urine

In this paper we describe our results of the determination of the isoenzymes of alpha-amylase in serum and urine with two monoclonal antibodies, using 4,6-ethylidene-protected 4-nitrophenylmaltoheptaoside as substrate. For comparison we have used the wheat-germ inhibitor method with blue starch as substrate. The differences observed between each method were small. The technique using monoclonal antibodies is easy and reliable and can, therefore, replace the wheat-germ inhibitor method.

Total amylase and pancreatic isoamylase in serum and urine: considerations from data on biological variation

The analytical, within-subject and between-subject components of variation were estimated for amylase activity and pancreatic isoamylase activity in serum measured using newer analytical methods. Desirable analytical imprecisions based on within-subject variation were CV less than or equal to 4.4% and CV less than or equal to 7.0%, respectively. Conventional population-based reference intervals were not useful because of marked individuality; clinical decision-making points should be derived from the desired sensitivity and specificity. Serial results must change more than about 30% and 40% respectively before significance (P less than or equal to 0.05) can be claimed. Similar data on total amylase and pancreatic isoamylase activities in random and first morning urines showed that the use of conventional reference intervals was appropriate. Very large changes (greater than 100%) were required before a difference in serial results was significant. Calculation of the urine amylase/creatinine ratio appeared to confer no advantage. Derivation of the ratio of pancreatic isoamylase to total amylase activity in serum or urine was unlikely to provide additional information of value in either diagnosis or monitoring.

Evaluation of a new assay for pancreatic amylase: performance characteristics and estimation of reference intervals

We have evaluated a new assay for the specific determination of pancreatic (P) isoamylase, the principle being based on a synergistic inhibitory effect of two monoclonal antibodies directed towards salivary (S) amylase. After 3 min incubation, activities were determined with maltoheptaoside-PNP as substrate on a Hitachi 705 analyzer at 25, 30 and 37 degrees C, respectively. Coefficients of variation ranged from 0.6 to 5.4% for within-run and 2.1 to 9.9% for day-to-day precision. Linearity held up to 1200 U/L (25 degrees C) and 2300 U/L (37 degrees C). Comparison of the new method with the wheat germ inhibitor technique showed an excellent correlation, with coefficients ranging from 0.990 to 1.00. Using purified P- and S-amylase we observed no inhibiting cross-reactivity of the antibodies with the P-isoenzyme, but an incomplete blockage of S-amylase: residual activity was approximately 2% at 25 and 30 degrees C, and 2.5% at 37 degrees C. The distribution pattern of P-, S- and total amylase activity in serum of healthy subjects was only slightly skewed to the right. We found neither an influence of sex nor of age on the reference ranges. In random urine samples, distribution of activities was strongly skewed. However, if the activity was related to the urinary creatinine concentration, an approximately normal distribution was obtained, allowing, as in serum, the establishment of upper and lower reference values.