Bentiromide Test Research Articles

Risk Factors for Pancreatic Stone Formation in Type 1 Autoimmune Pancreatitis: A Long-term Japanese Multicenter Analysis of 624 Patients.

Autoimmune pancreatitis (AIP) has the potential to transform into chronic pancreatitis with pancreatic stone involvement. This retrospective investigation sought to clarify the risk factors for stone formation in type 1 AIP. Questionnaires on patients with type 1 AIP were sent to 22 high-volume medical centers across Japan to compare the clinical features of patients with and without pancreatic stone formation. Of the completed records on 624 type 1 AIP patients, 31 (5%) had experienced pancreatic stones. Median follow-up duration was 1853 days. Bentiromide test values at diagnosis were significantly lower, and hemoglobin A1c values after corticosteroid treatment were significantly higher in patients with pancreatic stones. Imaging results disclosed that pancreatic atrophy and hilar or intrahepatic bile duct stenosis were significantly more frequent in patients with pancreatic stone formation. Pancreatic head swelling tended to be more frequent in this group as well. On the other hand, a shorter follow-up period was associated with the nonformation of pancreatic stones. The increased frequency of pancreatic head swelling in type 1 AIP patients exhibiting pancreatic stones indicated a propensity for pancreatic juice stasis with subsequent stone development and pancreatic dysfunction occurring over longer periods of disease duration.

Recovery from Exocrine Pancreatic Insufficiency in a Patient with Fulminant Type 1 Diabetes

A 34-year-old man was admitted to our hospital with diabetic ketoacidosis due to fulminant type 1 diabetes. The patient's pancreatic exocrine and endocrine functions were as follows: the bentiromide (PABA) test value on day 14 was 33.9%, thus indicating exocrine dysfunction. One year and a half later, the PABA test value had improved to 71.0%. On the other hand, the serum C-peptide level after meal ingestion was under the detection limit. The mechanisms underlying pancreatic exocrine abnormalities seem to be different from those underlying accelerated pancreatic beta-cell failure in patients with fulminant type 1 diabetes.

Diagnosis of Protein-Losing Gastroenteropathy By Using Double Balloon Enteroscopy (DBE) and Videocapsule Endoscopy (VCE)

Background and Aims: Protein-losing gastroenteropathy often remains undiagnosed with conventional imaging modalities. Double balloon enteroscopy (DBE) and videocapsule endoscopy (VCE) enabled visual diagnosis of diseases deep in the small bowel. In this study, We aim to determine the usefulness of VCE and DBE for the diagnosis of protein-losing gastroenteropathy. Methods: Of 553 consecutive patients who underwent DBE between June 2003 and November 2008, 12 patients (7 men and 5 women, mean age 45.0) had presented with hypoproteinemia (n=12), edema (n=8), chronic diarrhea (n=6), anemia (n=6), ascites (n=1), and pleural effusion (n=1). These 12 patients were diagnosed as protein-losing gastroenteropathy by 99mTc-HSA-D scintigraphy and/or α1-antitrypsin clearance. They underwent DBE, VCE and double-contrast fluoroscopic enteroclysis, then the diagnostic yields of these examinations were compared. To rule out malabsorption syndrome, fecal Sudan III stain, D-xylose test, and bentiromide test was performed. Results: Final diagnosis were as follows; primary lymphangiectasia (n=3), non specific multiple ulcers (n=3), amyloidosis (n=2), simple ulcer syndrome (n=1), malignant lymphoma (n=1), secondary enteropathy associated with heart failure (n=1), and liver cirrhosis (n=1). DBE showed abnormal findings in 9/12 (75.0%) and enabled final diagnosis in 10 of 12 (83.3%) in addition to pathologic findings of biopsy specimens. VCE showed abnormal findings in 4/5 (80%) and enabled final diagnosis in 2/5(40%). fluoroscopic enteroclysis showed abnormal findings and enabled final diagnosis in 2/7 (28.6%). One patient could not be diagnosed as primary lymphangiectasia by VCE or DBE with biopsy in life and died of congestive heart failure. Autopsy revealed lymphangiectasia in the submucosal layer but not in the mucosal layer, which had caused no typical findings in the biopsy specimens at DBE. For evaluation of malabsorption syndrome, fecal Sudan III stain was performed in 4 patients, a D-xylose test in 2, and a bentiromide test in 4, but all was negative. Treatment was as follows; albumin infusion (n=7), elemental diet (n=6), corticosteroid (n=5), diuretic (n=5), octreotide (n=3), tranexamic acid (n=1), low fat diet with medium-chain triglycerides (n=1), 5-aminosalicylic acid (n=1), chemotherapy (n=1). Conclusions: Non-invasive visual observation throughout the small bowel at VCE and pathologic findings by biopsy specimens at DBE was useful for the diagnosis of protein-losing enteropathy. As biopsies at DBE were impossible to detect submucosal lymphangiectasia in one case, boring biopsy, jumbo biopsy, or enteroscopic mucosal resection may have been useful.

EFFECT OF EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY AND ENDOSCOPIC TREATMENT ON SYMPTOMS AND PANCREATIC FUNCTION IN PANCREATOLITHIASIS

Aims: To investigate the efficacy of extracorporeal shockwave lithotripsy (ESWL) combined with endoscopic treatment for pancreatolithiasis and assess the pancreatic functions after treatment.Patients: Forty‐eight cases with pancreatolithiasis in the main pancreatic duct (MPD) treated by ESWL combined with endoscopic treatments were investigated.Methods: The disappearance rate of abdominal symptoms, the frequency of admission for acute exacerbation of pancreatitis before and after treatment, the relationship of removal of pancreatic stones with recurrence and stricture of the MPD, and pancreatic functions before and after treatment were examined.Results: Treatment for pancreatolithiasis improved symptoms in 95.1% and significantly reduced the frequency of admission for 1 year from 1.4 to 0.2 on average. Pancreatic stones were excellently eliminated in 93.8%. Even in cases complicated with the stricture of MPD, combination with endoscopic techniques provided treatment efficacy comparable to that in cases without such complications. The Bentiromide test significantly improved within 3 months after treatment. It improved 1–2 and 2–3 years after treatment but there was no significant difference. Endocrine functions were maintained in 93.6%, 74.3%, 66.7%, and 64.3% within 3 months, 1–2 years, 2–3 years, and 3 or more years, respectively, after treatment.Conclusions: ESWL combined with endoscopic treatment provides comparable treatment efficacy in cases with and without stricture of the MPD. Treatment for pancreatolithiasis is useful for not only alleviating abdominal symptoms but also maintaining pancreatic exocrine function and management of the diabetes.

THE EFFICACY OF ENDOSCOPIC PANCREATIC STENTING FOR THE TREATMENT IN PATIENTS WITH CHRONIC PANCREATITIS

Purpose: Endoscopic pancreatic stenting (EPS) is increasingly used to decompress the pressure of the main pancreatic duct (MPD) in chronic pancreatitis (CP). The proper duration of the stent placement, however, has not been fully investigated. The aim of this study is to evaluate the clinical benefits of EPS in patients with CP. Methods: The medical records of 61 consecutive patients (male 43, female 18) from March 1993 to October 2003 are reviewed. They all had pancreatic pain and severe MPD stenoses in head or body of the pancreas. Forty-nine patients received 80 plastic stents (7F or 10F). The stents were removed when they were regarded as being dysfunction by ultrasoundgraphy or when the single duration was over 12 months. New one was employed when ERP showed no improvement of the MPD stenosis after the removal of the old one. We evaluated the stent survival time, which was defined as being well drained with no MPD dilatation and pain relief. We also evaluated adverse events such as stent occlusion and dislocation. As for long-term results (over 36 months), we compared the relapse of pain, MPD diameter and pancreatic exocrine function (bentiromide test) between two groups: EPSs group, including fourteen patients who received EPS and Non-EPS group, including twelve patients with MPD stenoses who had not employed EPS. Results: 50% stent survival time of 10F-EPS was estimated as 320 days by Kaplan-Meier analysis and was significantly longer than that of 7F (82 days). Mild obstructive pancreatitis occurred in 2 patients at 64 days and 192 days. The relapse rate of pain in EPSs is 21% (3/14), which was lower than that of Non-EPS (50%:6/12). The MPD diameters in EPSs and Non-EPS changed from 6.1mm to 4.0 mm, 5.5 mm to 6.2 mm, respectively, with statistical significance. Pancreatic exocrine function was more preserved in EPSs than Non-EPS. Conclusions: EPS had clinical benefits especially in pain relief and preservation of pancreatic exocrine function for severe MPD stenosis in CP.

Pancreatic stenting for the preservation of pancreatic function in chronic pancreatitis with stricture

Background: Although many reports have documented pain relief achieved by pancreatic stenting, the effect of stenting on pancreatic function is less clear. In addition, the effects of stent caliber and patency have not been considered in most previous studies. Pain and pancreatic function after stenting of the main pancreatic duct (MPD) were examined.Methods: Records of 24 patients with chronic pancreatitis who had an MPD stricture treated with a 10‐Fr stent from June 1996 to June 2002 were reviewed. The average age was 57.0 ± 1 years, and the male : female ratio was 7 : 1. Eleven patients had diabetes mellitus. Stent patency, pancreatic pain and pancreatic endocrine and exocrine function were examined before stenting and 6 months after stenting. Stenting was continued for 1 year or more, with repeated stent exchange every 3 months.Results: The stent became occluded in 29% of cases, migration occurred in 15% of cases, and the 50% patency time was 125 days. Pancreatic pain was relieved by stenting in all cases. The diameter of the MPD, the Bentiromide test value, weight and body mass index were improved.Conclusion: Stenting relieves blockage of the main pancreatic duct and provides both pain relief and preservation of residual pancreatic function.

Critical Review of Diagnostic Methods Used in Chronic Pancreatic Disease

This paper provides a balanced assessment of the various pancreatic function tests and imaging techniques used in the differential diagnosis of chronic pancreatic disease. Function tests that study the digestive capacity of the pancreas (fat absorption of dietary lipids, fluorescein- or radiolabelled fats, bentiromide test, etc) have high specificity, but very low sensitivity. This is because 90% of pancreas has to be destroyed before steatorrhea or creatorrhea occurs. Tests that directly measure pancreatic bicarbonate and protein secretion (secretin test, etc) are more accurate and may detect pancreatic dysfunction even before anatomical changes occur. Measurement of pancreatic enzymes in serum or urine, or the decreased decline of serum amino acids during their incorporation into pancreatic enzymes, are not sufficiently sensitive or specific to help diagnose pancreatic disease. Sensitive and specific tumour markers are not yet available. Thus screening tests are not cost-effective - if they are negative, they do not exclude pancreatic disease; and if positive, they have to be confirmed by more specific tests. Imaging techniques are the most commonly used methods of investigation. The usefulness of abdominal survey films, barium studies, percutaneous transhepatic cholangiography, endoscopic retrograde cholangiopancreatography (ERCP), ultrasonography, computed tomographic scan, magnetic resonance imaging and endoscopic ultrasonography is critically reviewed. Most of the radiological methods can be combined with cytology or biopsy. Histology demonstrating malignancy establishes this diagnosis, but negative biopsies do not exclude malignant tumours. Presently only ERCP and endoscopic ultrasound can diagnose cancers sufficiently early to allow for possible `curative' surgery, and only endoscopic ultrasound is capable to stage tumours for the assessment of resectability.

Prevalence and clinical features of chronic pancreatitis in southern india

We have conducted a field study in India in the state of Kerala involving 28,567 inhabitants to determine the prevalence and clinical features of chronic pancreatitis of the tropics (CPT), an illness that is endemic in several regions of India. Selection criteria for the present study included: 1. Characteristic abdominal pain; 2. Evidence of diabetes mellitus; and 3. Evidence of malnutrition/malabsorption. A diagnosis of chronic calcific pancreatitis (CCP) was established by evidence of either 1, 2, or 3 plus X-ray evidence of pancreatic calculi. Diagnosis of noncalcifying chronic pancreatitis (NCCP) was established by 1, 2, or 3 plus an abnormal ultrasound of the pancreas and an abnormal bentiromide test. CPT was discovered among 36 individuals (prevalence 1:793). Strict entry criteria may have excluded additional cases. CPT was far advanced at the time of diagnosis in that 28 had evidence of calcification, 19 had diabetes mellitus, and 27 had an abnormal bentiromide test. The major differences from previous hospital-based studies were female predominance (male/female ratio, 1:1.8), onset of disease at an older age (mean 23.9 yr), and evidence of milder disease. We conclude that previous hospital-based reports that CPT is a severe illness with a male predominance may reflect greater access of seriously ill individuals in general and males in particular to medical care.

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

We assessed the diagnostic capability of the bentiromide test using a high-pressure liquid-chromatography method to analyze p-aminobenzoic acid and its metabolites in plasma as an indirect measure of exocrine pancreatic function. Mean total amine concentration in pancreatic-insufficient subjects was significantly lower than in control subjects. There were 3 of 15 false-negative results and no false-positive results. We conclude that this chromatographic method is an effective means of analyzing p-aminobenzoic acid and its metabolites after ingestion of bentiromide.

The bentiromide test using plasma p-aminobenzoic acid for diagnosing pancreatic insufficiency in young children: The effect of two different doses and a liquid meal

The bentiromide test was evaluated using plasma p-aminobenzoic acid as an indirect test of pancreatic insufficiency in young children between 2 months and 4 years of age. To determine the optimal test method, the following were examined: (a) the best dose of bentiromide (15 mg/kg or 30 mg/kg); (b) the optimal sampling time for plasma p-aminobenzoic acid; and (c) the effect of coadministration of a liquid meal. Sixty-nine children (1.6 ± 1.0 years) were studied, including 34 controls with normal fat absorption and 35 patients (34 with cystic fibrosis) with fat maldigestion due to pancreatic insufficiency. Control and pancreatic insufficient subjects were studied in three age-matched groups: (a) low-dose bentiromide (15 mg/kg) with clear fluids; (b) high-dose bentiromide (30 mg/kg) with clear fluids; and (c) high-dose bentiromide with a liquid meal. Plasma p-aminobenzoic acid was determined at 0, 30, 60, and 90 minutes then hourly for 6 hours. The dose effect of bentiromide with clear liquids was evaluated. High-dose bentiromide best discriminated control and pancreatic insufficient subjects, due to a higher peak plasma p-aminobenzoic acid level in controls, but poor sensitivity and specificity remained. High-dose bentiromide with a liquid meal produced a delayed increase in plasma p-aminobenzoic acid in the control subjects probably caused by retarded gastric emptying. However, in the pancreatic insufficient subjects, use of a liquid meal resulted in significantly lower plasma p-aminobenzoic acid levels at all time points; plasma p-aminobenzoic acid at 2 and 3 hours completely discriminated between control and pancreatic insufficient patients. Evaluation of the data by area under the time-concentration curve failed to improve test results. In conclusion, the bentiromide test is a simple, clinically useful means of detecting pancreatic insufficiency in young children, but a higher dose administered with a liquid meal is recommended.

Basal chymotrypsin secretion and the bentiromide test in chronic pancreatitis

The bentiromide test appears to be useful in detecting chronic pancreatitis with measurements of urinary excretion of PABA after the oral administration of BT-PABA. Although the bentiromide test may reflect abnormal pancreatic chymotrypsin secretion, the test has not previously been correlated with basal pancreatic chymotrypsin secretion. Normal volunteers and patients with chronic pancreatitis underwent the bentiromide test (500 mg) and intubation with a multilumen duodenal catheter. Duodenal juice was analyzed for chymotrypsin, and the content, concentration, and output were determined. In addition, the ability of the duodenal juice to generate PABA from BT-PABA was measured and correlated with the other secretory studies. Normal subjects had a urinary PABA excretion of 81.4 ± 4.1 %. Two groups of subjects with chronic pancreatitis were identified, one with a normal mean PABA excretion, 73.9±9%, and the other with a decreased mean PABA excretion, 35.5 ±5%. The basal chymotrypsin output of 18.2±8 U/min and the duodenal juice generation of PABA, 0.1 ±.04 ug/mL in the subjects with chronic pancreatitis were both less than found in normals, 105.1 ±48.6 U/min and 0.4 ±.04 μg/mL (p<.05). The percent PABA excretion did not correlate significantly with the three basal secretory studies. Duodenal juice PABA generation correlated only with the basal concentration of chymotrypsin (r = 7, p<.01). It appears that the bentiromide test, although capable of detecting subjects with chronic pancreatitis, may not accurately reflect the amount of basal duodenal chymotrypsin.

Exocrine pancreatic function after gastrectomy: Specificity of indirect tests

We compared intraindividually the specificity of indirect pancreatic function tests before and after total (n = 4; Roux-en-Y) or subtotal (n = 6; Billroth II) gastrectomy. Before gastrectomy only 1 patient showed a falsely pathological result with the pancreolauryl test (90% specificity), while the results of all the other tests were correctly normal (100% specificity using the usual cutoff limits). After gastrectomy the respective specificities were as follows: pancreolauryl test 10%, bentiromide test 70%, fecal chymotrypsin 70%, and plasma amino acid consumption test 100%. There was no obvious difference in the reduction of specificity between subtotal and total gastrectomy. The respective preoperative to postoperative changes in the median test data were as follows: plasma amino acid consumption test +21%, bentiromide test −12%, fecal chymotrypsin −51%, and pancreolauryl test −53%. It is concluded that after gastrectomy only the plasma amino acid consumption test is unaffected by postoperative anatomic alterations.

Simplified oral pancreatic function test.

The standard Bentiromide test and a new modified test using p-aminosalicylic acid (PAS) as a pharmacokinetic marker for p-aminobenzoic acid (PABA) have been evaluated in the detection of pancreatic exocrine insufficiency in children. The conventional two day test using a colorimetric assay for urinary PABA discriminated poorly between five children with pancreatic insufficiency and 13 others with normal pancreatic function. Two further groups of patients, comprising 28 with pancreatic exocrine insufficiency and 20 with normal pancreatic function underwent the modified test, and urine samples were analysed by high performance liquid chromatography. The results showed a complete separation between groups. The use of PAS eliminates a number of sources of error inherent in a two day Bentiromide test and provides a simplified and accurate diagnostic test for pancreatic insufficiency. The PABA-PAS modified test enables collection of the urine to be done during a single six hour period.

The development of the chymotryptic activity during postnatal life using the bentiromide test.

The chymotryptic activity was assessed in 40 newborns and infants age 3-180 days using the NBT-PABA test. Nine newborns were studied serially at different age periods. A group of 18 cystic fibrosis patients and a group of 17 healthy children served as pancreatic insufficient and pancreatic sufficient controls, respectively. The results demonstrate a gradual increase with age of chymotryptic activity, approaching the levels of older children at about 180 days. The newborns who were studied serially demonstrated an individual pattern of increase in their chymotryptic activity. In the first days of life, newborns show low chymotryptic activity similar to that found in cystic fibrosis patients.

Exocrine pancreatic function in chronic urticaria patients is normal.

25 patients with chronic urticaria suspected to be of 'alimentary origin', were studied for a quantitative or qualitative deficiency of pancreatic enzyme secretion. All showed a normal fecal chymotrypsin excretion and 23/25 a normal bentiromide (PABA) and pancreolauryl test. In 2 females the urinary PABA and pancreolauryl tests were borderline pathological. This does not support the hypothesis that a pancreatic deficiency (of the kind which could be identified with the methods used) is associated with chronic urticaria in patients in whom improvement of urticaria occurs under a hydric or low antigenic diet.

Bentiromide test is not affected in patients with small bowel disease or liver disease.

The bentiromide test reliably detects exocrine pancreatic insufficiency. The synthetic peptide attached to p-aminobenzoic acid (PABA) is cleaved by chymotrypsin, PABA is absorbed in the small intestine, partially conjugated in the liver, and excreted in the urine. It has been claimed that the bentiromide test is abnormal not only in patients with pancreatic insufficiency but also in patients with small bowel or liver disease because of impaired PABA absorption or conjugation, respectively. This study prospectively evaluates the bentiromide test in 12 patients with small bowel disease and 18 patients with biopsy-proven liver disease. One of 30 patients had an abnormal bentiromide test. Cumulative 6-h urinary arylamine excretion and plasma PABA concentration, 2 h after administration, were in the same range as healthy controls. We conclude that the bentiromide test is not affected by small bowel or liver disease. An abnormal test is virtually diagnostic for exocrine pancreatic insufficiency.

Exocrine pancreatic function as determined in a same-day test with use of bentiromide and p-aminosalicylic acid.

We describe a new approach to the bentiromide test of exocrine pancreatic function, p-Aminosalicylic acid (PAS), a compound closely related to the bentiromide fragment p-aminobenzoic acid (PABA), is used as a marker of the pharmacokinetic behavior of PABA to derive a PABA excretion index. This index is identical to that derived with [14C]-PABA. Concentrations of both PABA and PAS are measured in urine by "high-performance" liquid chromatography, which avoids the drug interferences encountered with established assays of PABA. We discuss the practical and diagnostic advantages of this new approach to the bentiromide test.

Altered PABA pharmacokinetics in cystic fibrosis. Implications for bentiromide test.

The bentiromide test has been proposed as a useful noninvasive method for assessing exocrine pancreatic function in cystic fibrosis (CF) patients. Following oral administration, this peptide is selectively cleaved by pancreatic chymotrypsin liberating PABA which is passively absorbed. Recent studies have suggested that PABA measured in plasma is superior to the more established method of estimating urinary recovery of this marker. However, in using the plasma test in CF patients, one makes the assumption that the PABA marker has similar distribution and elimination patterns in normal and CF subjects. Since many drugs display altered pharmacokinetics in CF patients, we studied the disposition of PABA following ingestion of free PABA in six controls (age 19-28 years) and 18 CF patients (13-18 years; seven steatorrheic and 11 nonsteatorrheic). Elimination of T1/2 of PABA was significantly shorter in CF patients (58 +/- 21 min) compared to controls (93.5 +/- 28) (P less than 0.005). PABA clearance was similar in the control and CF patients (2.99 +/- 1.21 and 3.27 +/- 1.02 ml/min/kg, respectively). PABA distribution volume was smaller, although not significantly so, than in the controls (268 +/- 107 vs 376 +/- 140 ml/kg). Good correlation was found between PABA distribution volume and T1/2 (r = 0.51 P less than 0.02). Our simulation data suggest that altered pharmacokinetics of PABA in CF patients would cause their PABA levels to be 7% lower than controls at 90 min, 18% at 120 min, 29% at 150 min, and 38% at 180 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Bentiromide test for assessing pancreatic dysfunction using analysis of para-aminobenzoic acid in plasma and urine: Studies in cystic fibrosis and Shwachman's syndrome

We evaluated the bentiromide test by analyzing para-aminobenzoic acid (PABA) in plasma and urine (a) for the identification of patients with complete pancreatic insufficiency and (b) as an alternative to the secretin-cholecystokinin test. Nine control subjects, 18 patients with cystic fibrosis, and 4 patients with Shwachman's syndrome were studied. Based upon the secretin-cholecystokinin test, pancreatic function was judged to be < 0.1% of normal in 7 patients with cystic fibrosis and malabsorption and between 0.7% and 90% of control values in 11 patients with cystic fibrosis and 4 patients with Shwachman's syndrome without malabsorption. The bentiromide test was performed in two stages: first with bentiromide alone, then with equimolar free PABA. After ingestion of free PABA, the plasma profile and urinary excretion of PABA were comparable in controls, patients with cystic fibrosis, and patients with Shwachman's syndrome. Thirty minutes after oral bentiromide, plasma PABA values in patients with and without malabsorption were significantly lower than in the control group. From 60 to 180 min after ingestion, plasma PABA levels in patients without malabsorption were no different from controls; whereas levels in patients with malabsorption were significantly lower than in controls and in those without malabsorption, reaching the highest significance at 90 min. Similar results were obtained when the urinary excretion of PABA was considered. Only the 90-min plasma test reliably detected cystic fibrosis patients with steatorrhea, however. Duodenal colipase output was highly correlated with both the 90-min plasma test and the urinary excretion of PABA, with similar results for lipase and trypsin output. Reliable detection of pancreatic dysfunction, nevertheless, was not obtained even with the plasma test, in cystic fibrosis patients with > 5%–10% of the mean normal enzyme output. In patients with Shwachman's syndrome, none of whom had malabsorption, the plasma and urinary test failed to detect pancreatic dysfunction even with enzyme output as low as 1% of normal.

Colorimetric plasma assay for the bentiromide test (BT-PABA) for exocrine pancreatic insufficiency

Bentiromide is a synthetic peptide, N-benzoyl- l-tyrosyl- p-aminobenzoic acid, which has been used as a test for exocrine pancreatic function. Following oral administration, bentiromide is hydrolyzed by chymotrypsin to yield free p-aminobenzoic acid (PABA) which is absorbed, conjugated and excreted in the urine. The PABA conjugates reach their peak levels in blood in 90–120 min. Healthy individuals have higher levels of PABA than patients with pancreatic insufficiency. A simple, accurate, and precise method for the determination of PABA in blood has been developed and validated. The plasma (1 ml) is deproteinized by perchloric acid. The conjugates are hydrolyzed and the total PABA is determined colorimetrically by the Bratton-Marshall test. The standard curve in plasma is linear up to 8 μg/ml of PABA. A similar semimicro method using 200 μl of plasma suitable of pediatric samples shows comparable results. Average analytical recovery is 97% and precision studies of pooled within-run and total between-run showed CV% of 5.0 and 5.7%, respectively.