How should I evaluate and manage a 28-year-old woman with persistent isolated serum amylase elevation (~250 U/L) and dull right-sided abdominal pain, normal lipase, prior normal abdominal ultrasound and CT, mild gastritis on endoscopy, and no other symptoms?

Approach to Isolated Amylase Elevation with Normal Lipase

This patient does not have acute pancreatitis, and the isolated amylase elevation (~250 U/L, which is less than 3 times the upper limit of normal) should not be pursued as a pancreatic disorder. 1, 2, 3

Why This Is Not Pancreatitis

The diagnostic criteria for acute pancreatitis require enzyme elevation ≥3 times the upper limit of normal (ULN), and this patient's amylase of 250 U/L does not meet this threshold. 2, 3 Additionally:

• Normal lipase with elevated amylase argues strongly against pancreatic pathology, as lipase is more specific for pancreatic disease and remains elevated longer (8-14 days vs 3-7 days for amylase). 1, 2
• When lipase is significantly elevated (>3× ULN) but amylase is normal, pancreatitis may still be present, but the reverse pattern (elevated amylase with normal lipase) typically indicates non-pancreatic sources. 4
• A serum lipase >3× normal has 100% sensitivity and 99% specificity for acute pancreatitis, while amylase has only 72% sensitivity. 5

Sources of Isolated Amylase Elevation

The amylase elevation in this patient likely originates from non-pancreatic sources: 6

• Salivary glands (chronic alcoholism, postoperative states, anorexia/bulimia, or direct salivary pathology) 6
• Gastrointestinal sources including the mild gastritis already documented on endoscopy 4, 7
• Renal insufficiency causing decreased clearance 4, 6
• Macroamylasemia (abnormally high-molecular-weight amylase complexes) 6
• Bowel pathology (obstruction, ischemia) causing absorption of luminal amylase 6

Recommended Diagnostic Approach for Right-Sided Pain

Given the new right-sided abdominal pain, focus on evaluating causes unrelated to pancreatitis:

Immediate Workup

• Obtain comprehensive metabolic panel to assess renal function (creatinine, BUN) and electrolytes, as renal insufficiency commonly causes isolated amylase elevation. 4, 6
• Repeat abdominal ultrasound specifically evaluating the right upper quadrant for cholecystitis, biliary pathology, or hepatic lesions, since the pain has shifted from upper abdomen to right-sided. 1
• Consider amylase isoenzyme testing (pancreatic vs salivary-type) to definitively determine the source of elevation, which will guide further workup. 6

If Initial Workup Is Unrevealing

• Obtain contrast-enhanced CT abdomen to evaluate for occult pathology including appendicitis, bowel obstruction, or other intra-abdominal processes that can cause both right-sided pain and amylase elevation. 4, 7
• Check serum triglycerides and calcium only if there is genuine clinical suspicion for pancreatitis despite normal lipase (which there should not be in this case). 1, 2

Critical Pitfalls to Avoid

• Do not pursue this as pancreatic disease based solely on modest amylase elevation with normal lipase. 3, 4
• Do not order serial pancreatic enzyme measurements or repeat CT scans looking for pancreatitis, as the diagnostic criteria are not met. 2, 3
• Do not delay evaluation of the right-sided pain by focusing on the amylase number—the pain location change suggests a different process entirely. 7
• Do not assume any amylase elevation indicates pancreatitis, especially when <3× ULN and discordant with lipase. 3, 5

Management Strategy

Treat the underlying cause once identified (e.g., cholecystitis, renal dysfunction, gastritis exacerbation), not the amylase number itself. 7 The isolated amylase elevation is likely an incidental finding or related to her known gastritis, and does not require specific pancreatic-directed therapy or monitoring. 4, 6