Liver Fibrosis Testing: Now More Options than Biopsy
Okay, you saw new treatments on TV for Hepatitis C that can actually cure the disease. You requested a screening during your annual physical and the results came back positive for the virus. Before you discuss a plan of treatment with your doctor, key questions must be answered. “How much damage has the virus caused? Is the liver scarred? Can the liver get better?” Physical examination can’t answer these questions, yet the doctor must determine the extent of liver fibrosis (scarring). The gold standard is liver biopsy but there are valid concerns about this invasive procedure. Liver biopsy has a potential for not only sampling/interpretation error (all pathologists do not always get the same interpretation of the biopsy sample) but also, although rare, potentially life-threatening procedure-related complications. After a biopsy, which is usually done outpatient in a hospital setting, you must lay flat in the recovery room for 6-8 hours. You cannot perform vigorous physical activity or lift anything over ten pounds for up to a week. This is to prevent the very small chance of serious bleeding. Here is a review of current and future screening techniques that do not require invasion of your liver, but each procedure has drawbacks.
Noninvasive Options for Fibrosis Assessment. Concerns are accuracy, subtle scarring (fibrosis) differences, cost and availability.
The proposed methods of fibrosis assessment in a variety of liver diseases are based on clinical, biochemical, and radiologic variables and are often used in combination. Specifically, the use of serum biomarkers of fibrosis, and several imaging tools to assess liver stiffness (fibrosis), have been introduced and validated. These noninvasive indicators of liver fibrosis offer an enhanced ability to predict treatment outcomes, thus improving your care. They will also tell if treatments are working.
Despite this recent progress, questions remain regarding the diagnostic accuracy, cut-off and threshold values for the degree of fibrosis. Cost, and broad applicability of each test should be answered with more data obtained through reviews of studies. Often a mix of the tests below must be used.
- HepaScore (also known as FibroScore)
- Enhanced liver fibrosis (ELF) panel and
- Fibrosis-4 (FIB-4) index, relatively inexpensive
The practical advantages of emerging serum biomarkers include their wide use and ability for many labs to get the same results, as well as their potential widespread availability. However, serum biomarkers often fail to tell the difference between lower levels of fibrosis. Nevertheless, biomarkers can be useful to monitor effectiveness of treatment.
For more information on each test, use your preferred search engine and go to MedScape.
- Transient Elastography (TE)
- Magnetic Resonance Elastography (MRE)
Transient Elastography (TE) relies on sonic detection of liver stiffness to predict liver scarring. TE is good for patients with chronic hepatitis. TE is also good for screening people who are otherwise healthy. This test has several distinct advantages: can be done quickly, results immediately available, and the test can be done in the outpatient clinic.
TE has some limitations. The results must be consistent with the how you look in an examination, and other test results (biochemical, radiologic, and endoscopic). In addition, liver stiffness (fibrosis) may be overestimated in the patient with obesity, cholestasis (bile can’t get from the liver to the gut), and heart failure. Appropriate cut-off values for fibrosis need to be fine-tuned.
FibroScan® tests for liver stiffness (scarring) and is not affected by obesity, cholestasis or heart failure. FibroScan is more accurate than biomarkers when compared to liver biopsy. This test can be good for patients with chronic Hepatitis C.
Magnetic Resonance Elastography (MRE) looks at sound waves through the liver. This test is showing promise for children, but hasn’t yet been validated compared to biomarkers. Obesity does not change results.
Ultrasonography sends acoustic radiation force impulses (ARFI) and rouses the tissue. The results are promising and has been shown to be similar to TE. This test can also look at the parenchyma (the actual liver cells) which is an advantage.
This is not the end of liver biopsy yet. Although these non-invasive techniques are decreasing the number of liver biopsies, the story is not complete. Researchers still need to compare strategies using TE, MRE, ARFI, and biomarkers, and look at combinations of tests. These tools are not yet used everywhere and the cost is not known for use large scale.
- Tucker ME. Noninvasive Liver Assessment: The US Plays Catch-up. MedScape. May 13, 2015. http://www.medscape.com/viewarticle/844590