Bentiromide test using liquid-chromatographic measurement of p-aminobenzoic acid and its metabolites for diagnosing pancreatic insufficiency in childhood

Untargeted Metabolomics for the Diagnosis of Exocrine Pancreatic Insufficiency in Chronic Pancreatitis

Background and Objectives: The clinical manifestations and course of chronic pancreatitis (CP) are often nonspecific and variable, hampering diagnosis of the risk of exocrine pancreatic insufficiency (EPI). Development of new, reproducible, and non-invasive methods to diagnose EPI is therefore a major priority. The objective of this metabolomic study was to identify novel biomarkers associated with EPI. Materials and Methods: We analyzed 53 samples from patients with CP, 32 with and 21 without EPI, using an untargeted metabolomics workflow based on hydrophilic interaction chromatography coupled to high-resolution mass spectrometry. Principal component and partial least squares-discriminant analyses showed significant between-group differentiation, and univariate and multivariate analyses identified potential candidate metabolites that significantly differed between samples from CP patients with EPI and those without EPI. Results: Excellent results were obtained using a six-metabolic panel to diagnose the presence of EPI in CP patients (area under the ROC curve = 0.785). Conclusions: This study confirms the usefulness of metabolomics in this disease setting, allowing the identification of novel biomarkers to differentiate between the presence and absence of EPI in CP patients.

Biochemical tests in diseases of the intestinal tract: their contributions to diagnosis, management, and understanding the pathophysiology of specific disease states

Biochemical testing plays a major role in the complete evaluation of patients with suspected or established intestinal disease. We have classified these tests according to the medium in which they are performed: breath tests, including isotopic and nonisotopic tests, fecal tests, urine tests, serum tests, tissue tests, and other tests. The principles of various tests are outlined, and the role of each test in the evaluation of particular gastrointestinal disorders is discussed.

Glycine conjugation of para-aminobenzoic acid (PABA): a quantitative test of liver function

OBJECTIVE

To evaluate glycine conjugation of para-aminobenzoic acid (PABA) to the hippurated metabolites, para-aminohippuric acid (PAHA), and para-acetamidohippuric acid (PAAHA) as a quantitative liver function test in patients with liver disease.

DESIGN AND METHODS

Serum concentrations of PABA and metabolites were measured by high pressure liquid chromatography in 24 controls and 50 patients with hepatobiliary disease.

RESULTS

Hippurate formation was significantly decreased in all patient groups with chronic liver disease versus controls. The hippurate ratio (% hippurated metabolites formed) correlated with severity of disease, serum albumin, and factor VII concentrations. PAHA concentration was a better prognostic indicator than factor VII concentrations in patients with acute liver disease; concentrations of zero correctly predicted a poor outcome in patients with fulminant liver failure.

CONCLUSIONS

Glycine conjugation of PABA may be useful as a quantitative liver function test in patients with hepatobiliary disease and as a prognostic index in patients with fulminant liver failure.

Biochemical tests in the diagnosis of chronic pancreatitis and in the evaluation of pancreatic insufficiency

Chronic pancreatitis (adults) and cystic fibrosis (children) are the most common diseases leading to exocrine pancreatic insufficiency that, when reduced to < 5% of normal function, is characterised by steatorrhoea. The pathogenesis of the former condition is outlined, and recent concepts are emphasized. Biochemical tests to detect pancreatic insufficiency and to identify pancreatic disease as the cause of steatorrhoea include: serum enzyme tests (lipase, amylase, trypsin); stool chymotrypsin; isotopic tests based upon the assimilation of [14C] lipids and starch or excretion of the isotope as breath CO2, as well as the dual-labelled Schilling test; oral function tests utilising substrates hydrolysed by pancreatic enzymes such as benzoyl tyrosyl-p-aminobenzoic acid and fluorescein dilaurate; and duodenal intubation studies following meal-induced or hormonal stimulation of the pancreas. The rationale for these tests and the cumulative clinical experience of their utility are reviewed. A recommended diagnostic strategy is briefly presented. The role of various biochemical procedures to evaluate the efficacy of pancreatic enzyme replacement therapy is also described.