A PATIENT’S GUIDE TO NON-INVASIVE TESTS (NIT)
The diagnosis and monitoring of liver disease can be confusing to patients. While most of us have heard of liver biopsies, not everyone knows about the variety of NITs that are currently in use.
While long considered the gold standard for diagnosing liver disease, invasive liver biopsy is an unpleasant procedures that carries its own set of risks. In addition, there are studies that indicate that a biopsy may be no more accurate than non-invasive tests. Our experience is that no one wants a liver biopsy. Here are some reasons why you might not want to have one:
So why is it the gold standard? Well for one, the FDA requires a biopsy to measure endpoints in clinical trials. Hopefully, that will change over time as the evidence mounts regarding the usefulness and accuracy of NITs. Also, it is the only test that directly analyzes tissue samples. That does provide histological advantages
The purpose of this page is to provide an overall understanding from the patient perspective of the NITs that are presently in use and the circumstances in which they are presently used. This will facilitate informed discussions with your physician regarding the alternatives available for detecting and monitoring potential liver disease.
NITs have a large and growing role in the detection, staging and monitoring of liver disease. Their use is advised if you have any of the risk factors (diabetes, obesity, high blood pressure, etc.) associated with Nonalcoholic Fatty Liver Disease (NAFLD) or Nonalcoholic Steatohepatitis (NASH). The goal is to detect the presence of this disease and monitor its progression. Most people will not see their disease progress to a serious stage but any one at risk should monitor their liver health.
NITs fall into two general categories : 1) blood or serum testing or 2) imaging technologies. Generally, the blood tests is done initially for patients having any of the risk factors or experiencing symptoms. Our experience is that these tests are not done in the normal course of business and you may have to request them from your doctor. If this testing indicates a concern, the next step is to proceed to imaging. This usually begins with a referral to a specialist and the performance of an ultrasound. If problems are indicated the progression would then be to more sophisticated imaging technologies where the appearance and characteristics of the liver can be viewed by technicians and doctors.
The following table provides general guidance on the use of the various forms of non-invasive testing
|Type of Test||What It Is||What It Does||When It is Used||Comments|
|Hepatic Panel||Blood tests which typically include measurement of albumin, ALT, AST, ALP, Bilirubin and Prothrombin time. Other test may also be included||Measures liver enzymes and how well the liver is performing its normal function in producing protein and clearing bilirubin. No predictive value.||Early-stage screening tool for patients who may be at risk for NAFLD and NASH||Easily accessible and repeatable. Can be ordered by general practitioners. Test results, though, do not always correlate with disease level. Tests can be normal even with advanced liver disease.|
|Blood Test + Algorithm|
2. FIB- 4
3. NIS- 4
Other tests are in development and may be available soon
|Application of proprietary algorithms to blood results and other factors (Age, BMI, etc.) to assess liver health. Specific blood results used varies by algorithm||Better assessment of liver health than raw results and adds an objective measure that may have predictive value.||Early-stage diagnostic when it is expected that patient may be developing NAFLD or NASH. Facilitates early intervention. Strong ability to rule out advanced disease.||Easily accessible and repeatable. The specific test to be used should be discussed with your physician. Very promising results in newly developed algorithms. Sometimes cannot rule out advanced liver disease.|
|Ultrasound||Sound waves with frequencies higher than the upper audible limit of human hearing||2D grayscale image of the liver. Provides ability to detect swollen liver. Allows subjective estimation of liver fat. Does not measure scarring.||Used when there is a strong suspicion of NASH. The liver fat assessment is a subjective determination. Must have at least 30% liver fat to be detected.||Performed in a hospital or outpatient facility. Not particularly useful as a diagnostic tool other than to measure liver size and to rule out lesions or diseases such as gallstones.|
|Fibroscan||An ultrasound device that measures liver fat and scarring. A probe from the device is used to test the velocity of sound waves which provides a measurement of liver stiffness and liver fat.||Produces a score used to assess liver health. Also used as part of a FAST score which combines liver stiffness, liver fat and blood results.||Generally prescribed when there is an indication of liver damage. Good screening tool to identify at-risk patients. Limited predictive value.||Generally performed in an office visit to a liver specialist or in a a clinic. Obesity, liver inflammation and ascites may interfere with measurements. Variability in results limits must be considered. Can be used in children.|
|MRI (magnetic resonance imaging)||A test that uses powerful magnets, radio waves and a computer to make detailed pictures inside your body.||May be suitable for detecting fatty liver and some of the hallmark features of liver cirrhosis (such as changes in liver shape, size or surface nodularity among others). However, it cannot detect NASH or early stage liver fibrosis. Excellent for monitoring patients with liver cirrhosis to detect liver cancer.||Provides information to be interpreted by a radiologist,||Performed in a hospital or specialized MRI facility. Typically ordered by a specialist|
|MRI - PDFF (Protein Density Fat Fraction)||Uses MRI technology to measure water and fat in a tissue. Water and fat protons have different resonance frequencies and can be separated for measurement purposes.||Measures the proportion of fat in the liver. The amount of fat has been shown to be highly predictive of NAFLD progression.||Provides information to be interpreted by a radiologist and/or a specialist.||Performed in a hospital or specialized MRI facility. Typically ordered by a specialist.|
|MRE (Magnetic resonance elastography)||Combines MRI imaging with low-frequency vibrations to create a visual map that shows stiffness of body tissues.||Assesses more of the liver than a Fibroscan. Detects advanced scarring (fibrosis) more accurately than the other methods described above.||Provided information to be interpreted by a radiologist and/or a specialist.||Performed in a hospital of specialized MRI facility. Typically ordered by a specialist|
|Liver Multiscan||Used advanced multi-parametric MRI-based technology to quantitively characterize liver tissue, providing a comprehensive analysis that can aid in diagnosis, risk stratification and monitoring of liver disease.||Provides complete information regarding the amount of liver fat, inflammation, disease activity and iron content. Assesses the entire liver.||Provides information to be interpreted by a radiologist and a doctor. Reports are patient-friendly and intuitive.||Performed in facilities with MRI capabilities. Typically ordered by a specialist. Utilizes MRI-PDFF as part of its analysis.|
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“I WAS TOLD I NEEDED TO LOSE WEIGHT JUST LIKE EVERY DOCTOR VISIT I EVER HAD.”TONY VILLIOTTI NASH PATIENT