Acute Pancreatitis: Likelihood Ratios

Introduction: Pancreatitis represents acute inflammation of the pancreas, most commonly due to alcohol or gallstones. Several of the diagnostic tests below can help to distinguish the etiology.

Note that several formulas have been developed to predict those pts who are more likely to have a complicated course of pancreatitis, including Ranson and Glascow/Imrie criteria and the APACHE II scoring system.

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Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Acute abdominal pain	2.5%	J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
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The likelihood ratios of findings for Acute Pancreatitis are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Poorly Diagnostic Findings
Finding	Result	+LR	-LR
[ + ] Anorexia		Sensitivity = 85%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Abdominal Rigidity		Sensitivity = 80%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Decreased Bowel Sounds		Sensitivity = 60%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] hearing loss		Sensitivity = 60%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Abdominal Tympany		Sensitivity = 60%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Pain radiating to Back		Sensitivity = 50%
The pain is often relieved by sitting up and bending forward. The pain is made worse by food. Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Guarding		Sensitivity = 50%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Shock		Sensitivity = 15%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Jaundice		Sensitivity = 15%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208
[ + ] Hematemesis		Sensitivity = 10%
Study: J Hepatobiliary Pancreat Surg. 2006;13(1):25-32. PMID: 16463208

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Elevated Serum Lipase	+ 0 -	100	0
>3x upper limit of normal. More than 2/3 of patients with acute pancreatitis with normal amylase will have elevated lipase. Lipase rises within 4-8 hours and remains elevated for 8-14 days. Note that lesser elevations of lipase in the context of nonspecific abdominal pain usually do not represent pancreatitis, with ~80% of patients having completely normal imaging (PMID 12522473). Also note that lipase may be elevated in other conditions such as hepatitis C, IBD, DKA, and renal failure (PMID 15653954). Study: Am J Gastroenterol. 2002 Jun;97(6):1309-18. PMID: 12094843
[ + ] Elevated Serum Lipase	+ 0 -	100	0
Study: no study specified.
[ + ] Urine Trypsinogen-2	+ 0 -	12	0
by dipstick Study: Am J Gastroenterol. 2002 Jun;97(6):1309-18. PMID: 12094843
[ + ] Immunoreactive Trypsinogen	+ 0 -	5.7	0
(rarely used) Study: Am J Gastroenterol. 2002 Jun;97(6):1309-18. PMID: 12094843
[ + ] Elevated Serum Amylase	+ 0 -	4.8	0.1
>300IU/ml Note that up to 32% of alcoholic pancreatitis patients may have normal serum amylase. In general, amylase is the first pancreatic enzyme to rise and also the first to fall in an episode of pancreatitis Study: Am J Gastroenterol. 2002 Jun;97(6):1309-18. PMID: 12094843
[ + ] Lipase to Amylase Ratio	+ 0 -	3.8	0.1
ratio > 2 - for alcoholic pancreatitis Study: Gastroenterology 1991 Nov;101(5):1361-6. PMID 1718808
[ + ] Abdominal US	+ 0 -	36	0.3
for gallstone pancreatitis Study: Pancreas. 1988;3(2):153-8. PMID: 3287369
[ + ] Elevated Urine Pancreatic Amylase	+ 0 -	23	0.3
A dipstick test with antibodies specific to pancratic amylase. Study: Scand J Clin Lab Invest. 1998 Dec;58(8):611-6. PMID: 10088197
[ + ] Elevated Serum Amylase	+ 0 -	inf	0.4
>1000IU/ml Study: Am J Gastroenterol. 2002 Jun;97(6):1309-18. PMID: 12094843
[ + ] Abdominal CT	+ 0 -	inf	0.5
for gallstone pancreatitis Study: Pancreas. 1988;3(2):153-8. PMID: 3287369
[ + ] Elevated ALT	+ 0 -	12	0.5
>150 U/l - for gallstone pancreatitis Study: Am J Gastroenterol. 1994 Oct;89(10):1863-6. PMID: 7942684