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Liver Biopsy Remains Gold Standard
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"ACP: Liver Biopsy Not Foolproof"
By Peggy Peck, Senior Editor, MedPage Today
Reviewed by Robert Jasmer, MD; Assistant Professor of Medicine, University of California, San Francisco
April 10, 2006
MedPage Today Action Points
* Explain to patients who ask that despite any failings, the liver biopsy remains the gold standard for assessing chronic liver disease.
Review
PHILADELPHIA, April 10 - Liver biopsy is considered a gold standard for staging chronic liver disease, but this gold standard is sometimes fool's gold, according to data reported here.
Because the biopsy relies on needle placement liver disease may be missed, said K. Rajender Reddy, M.D., director of hepatology and medical director of the liver transplantation program at the Hospital of the University of Pennsylvania.
For example, Dr. Reddy said at the American College of Physicians meeting, in one series cirrhosis was missed in up to 20% of biopsies and the grade of inflammation or state of fibrosis was consistently underscored.
He illustrated his point with a slide of a cross-sectional sample from a cirrhotic liver on which he overlaid biopsy needle placement. Needles placed in one location completely missed cirrhotic tissue, while a needle placed just a few millimeters away detected advanced cirrhosis.
As a result, "a patient may be told at one point that he or she has mild disease, only to find out a year later that the liver is cirrhotic," he said.
The risk of error can be reduced, he told internists attending a "Multiple Small Feedings of the Mind" hepatology update, by attention to specimen size and number of specimens.
"Adequate specimens are at least 1.5 cm long, but accuracy is better for specimens 2 cm long and the best results are obtained with specimens that are at least 2.5 cm long," he said. Likewise, specimens should be at least 1 mm wide but 1.4 mm is better and 2.0 mm is the best.
Moreover, he said that at least six portal triads are needed but "11 is better."
Dr. Reddy acknowledged that because liver biopsy is an invasive procedure both referring physicians and referred patients are often reluctant to undergo biopsy.
But the alternative, which would be use of indirect markers, "is not ready for prime time."
However, Dr. Reddy offered some tips about interpretation of those markers. The most common, he said, is the ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio. "When AST is higher, it suggests cirrhosis," he said.
Another non-invasive marker than may have some utility is AST:platelet ratio index, which is calculated as follows: AST:platelet ratio index = [(AST/ULN)/platelet count] X 100 where the platelet count is expressed as cells/uL and ULN stands for upper limit of normal. But this index has not been validated in clinical trials.
There are a number of tests of which the best known are FibroTest and ActiTest, both made by Oneida TheraDiagnostics Ltd. Both tests are recommended for use in assessing liver status following diagnosis of hepatitis C, but the tests are not intended as a substitute for liver biopsy.
Primary source: American College of Physicians
Source reference:
Reddy, I L "Multiple Small Feedings of the Mind: Hepatology, Infectious Diseases in the Office, Update on Treatment of ACS and CHF" MSFM
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