USEFULNESS OF LIPASE / AMYLASE RATIO IN ACUTE ... - medIND

Indian Journal of Clinical Biochemistry, 2009 / 24 (4)greater than 3.0 can be used to differentiate between alcoholicand non-alcoholic pancreatitis. Further the lipase to amylaseratio of greater than 3.0 can be used to differentiate severeAP from mild and moderate forms of AP. The aims andobjectives of the study were to (a) To collect data of patientsdiagnosed with acute pancreatitis in the past 5 years. Thedata should include age, sex, etiological factors proposed,CT findings and serum lipase and amylase. (b) To categorizepatients based on etiological factors into alcoholic and nonalcoholicand calculate the serum lipase to amylase ratio. (c)To categorize patients based on the ultrasound findings andcalculate their serum lipase to amylase ratio.MATERIALS AND METHODSWe conducted a retrospective study on patients attending theclinics of Gastroenterology and Emergency medicine betweenMay 2003 and May 2008. The data were retrieved from themedical records of the patients and compiled for the study.The study is on hospital-based south Indian population.One thousand one hundred and thirty two patients (768 maleand 364 female) with AP were selected for study. The diagnosisof AP is based on the evidence of two or more combination ofthe following presentations: at least three folds increase inserum amylase and / or lipase levels, in addition to history ofupper abdominal pain and further confirmed byultrasonography and/ or CT performed during the hospital stay.The majority of patients had come as out patient with a historyof abdominal pain of 2 to 3 days with varying degree that wereeventually admitted to the hospital. All patients withquestionable diagnosis of other possible abdominal conditionsand incomplete data collections were excluded in this study.All patients with clinical presentations suggestive of chronicpancreatitis such as pancreatic duct dilatation, calcificationsand malabsorption were excluded.576 patients had an etiology of pancreatitis by alcoholism (withan average alcohol intake of 75 g and above), 341 patientswith etiology of pancreatitis of biliary origin and 215 patientswere secondary to / associated with trauma, dyslipidemia, endstage renal disease and diabetes mellitus (labeled asmiscellaneous). The CT findings of 261 patients wereretrievable and were classified as per Balthazar criteria (2)into three groups: Grade Mild (n = 88): normal, local or diffuseenlargement of the pancreas; Grade Moderate (n = 82):pancreatic gland abnormalities associated with peripancreaticinflammation; Grade Severe (n = 91): fluid collection in one ormore location and / or the presence of gas in or adjacent tothe pancreas. The serum amylase and lipase concentrationwere analyzed at admission. The lipase to amylase ratio wascalculated after converting the values of serum lipase andamylase values into multiples of upper reference limit that wasused. The lipase / amylase ratio were also correlated withultrasound findings. The serum lipase and amylase wereanalyzed on DADE Behring automated analyzer with itsdedicated reagents. The photometric technique for serumamylase was done using CNPG3 substrate (3). The lipasewas done by method of Neumann et al (4). Statistical analysiswas performed using ANOVA tests, Non parametric test andZ test for comparison of the three groups based on severityby statistical package SPSS. The p< 0.05 was considered asstatistically significant.RESULTSOur study showed that alcoholic acute pancreatitis patients(n = 1125; 44 ± 9.6 years) were significantly younger thanthose with biliary (n = 578; 62.1 ± 14.3 years) andmiscellaneous pancreatitis (n = 429; 58.5 ± 6.3 years). Themean serum amylase levels were significantly lower inalcoholic group in comparison to non-alcoholic groups. Serumamylase values (reference values: 25 to 115 U/L) wereTable 1 : Levels of serum lipase / amylase ratio in different groupsAlcoholic AP Biliary AP Miscellaneous APNumber of patients (n) 576 341 215Age (years) 44 ± 9.6 62.1 ± 14.3 58.5 ± 6.3Male / Female ratio 569 / 7 116 / 125 88 / 127Serum amylase (U/L) (reference interval : 25 – 115 U/L) 923.4 ± 557.5* 1736.2 ± 390.7 * 535.8 ± 477.6 *Serum lipase (U / L) (reference interval : 114 – 286 U/L) 3226.3 ± 1384.7* 6064.5 ± 1640.8* 2132.3 ± 1210Serum lipase / amylase ratio 4.25 ± 2.33* 1.5 ± 0.61* 2.44 ± 1.6*The values are expressed as Mean ± SE. *p< 0.05, Statistically significant difference observed in serum amylase and serum lipase / amylase ratiobetween alcoholic, biliary and miscellaneous AP. Statistically significant difference observed in serum lipase between alcoholic and biliary AP,miscellaneous and biliary group but there was no statistically significant difference between miscellaneous and alcoholic AP groups (‘p’ value =0.07)362