What is NAFLD Fibrosis Score and What is it Used For?


Non-alcoholic fatty liver disease (NAFLD) is one of the very common liver conditions, if not the commonest. People who are overweight or obese are at very high risk for NAFLD. Other risk factors include diabetes and abnormal lipid levels. As much as 20 to 30 percent of adults in the Western world have NAFLD. It usually leads to a wide range of liver dysfunctions that affect virtually all the systems of the body. Some people with NAFLD only have a simple fatty liver, which involves only a buildup of fats in the liver. However, some others have fibrosis and inflammation, in addition to fat buildup. The NAFLD fibrosis score could help identify the likelihood of fibrosis if you have NAFLD.

When fibrous and inflammation are present, the form of NAFLS is called nonalcoholic steatohepatitis (NASH). This is a very serious and life-threatening condition. If you do not treat and manage it properly, your condition may deteriorate even further. The condition may progress into liver cirrhosis and, later on, to end-stage liver disease. These do not have a very good outlook. That’s why experts have developed a validated scoring system that can measure the likelihood of fibrosis and how advanced it is. This scoring system is not the gold standard for diagnosing fibrosis, but it is very accurate and very easy to calculate.

Why the Need for This Scoring System?

You may wonder why the need for this scoring system since it is not the gold standard. It is not far-fetched and we will explain it to you.

The gold standard for diagnosis fibrosis in NAFLD is an invasive procedure called a liver biopsy. This procedure involved removing a part of the liver tissue with a needle.

The sample of liver tissue will then go to the lab for evaluation. Aside from diagnosing fibrosis, the liver biopsy also assesses the disease activity. It can also be useful for monitoring how you are responding to NAFLD treatment.

If all these are possible with liver biopsy, why is there a need for a scoring system? The thing with liver biopsies is that they have risks and quite a few issues.

Firstly, there is a risk of bleeding. It is an invasive procedure. As such, it could cause bleeding. It could also cause visceral injury, and in rare cases, even death.

If that’s all, we would let it pass because fatal risks are very rare occurrences. But then, there are bigger issues.

A biopsy can only assess a small portion of the liver tissue. Think of how big the liver is. It is the largest organ inside your body. Then, imagine using a needle to take out a part of it. That is like a part out of 50,000.

Now, fibrosis is not usually evenly distributed across the different parts of the liver, even though it is diffuse. As such, the sample from a biopsy may not accurately represent what is happening in other parts of the liver.

This means that a biopsy may lead to inaccurate staging. Imagine if there is advanced stage fibrosis in a part of the liver. But the sample for biopsy is from a part where there is only mild fibrosis. This error can be fatal.

That’s not all. Remember that histologic assessments like biopsy are semi-quantitative. So then, observer errors may also occur.

Furthermore, being an invasive procedure, liver biopsy is not fit as a first-line screening tool. It can be a confirmatory tool. But it can’t be the first-line approach to NAFLD investigation.

These reasons justify the need for a non-invasive, all-encompassing screening tool for fibrosis. The NAFLD fibrosis scoring system meets these criteria. More so, it is reliable, easy to perform, reproducible, and quite cheap.

What Is The NAFLD Fibrosis Score?

The NAFLD scoring system for fibrosis is a noninvasive screening tool for detecting fibrosis in those with NAFLD. Experts have validated this tool. It can also be used to detect the stage of fibrosis, as well as monitor response to NAFLD treatment.

The good thing with this scoring system is that it makes use of readily available data. A few routine lab tests and your clinical information are the only data it requires.

The data they this score panel includes are as follows:

1. Values from routine lab tests

  • Serum glucose: This is a measure of how much glucose you have in your blood. The liver is your body’s reservoir of glucose. A dysfunctional liver will affect your blood glucose level.
  • Platelet count: This is a measure of how many platelets are in your blood. Your liver produces the hormone that regulates platelet production. As such, a dysfunctional liver would affect your platelet count.
  • Albumin levels: This is a measure of the amount of albumin in your blood. Your liver produces albumin from the proteins you eat. As such, when the liver is dysfunctional, albumin levels would be abnormal.
  • AST/ALT ratio: AST and ALT are liver enzymes. Their levels in the blood can tell the state of the liver.

2. Readily accessible clinical information

A lot of professional bodies have validated this scoring system. Usually, it is used for screening and not the final diagnosis. This means that if your score is low, your case would not need further investigation.

But if your score is high, you may have to do further diagnostic tests. Examples of such tests include elastography and liver biopsy.

The fibrosis score would also show if you are at risk. If that is the case, you would only need to go back for follow-up screening at periodic intervals.

You do not have to do any calculations. The calculation has been automated. All you need is to enter the values of the aforementioned data. The computer would calculate your score. You can even do this calculation online if you have all the required data.

How to Interpret Your Score

The score comes in a number. This is how it is interpreted:

  • Any score greater than 0.676 means there is likely advanced-stage liver fibrosis. You need to do a confirmatory test.
  • Any score that is less than -1.455 (take note of the negative sign) means it is unlikely that you have liver fibrosis. No further investigation is needed.
  • Any score that is greater than -1.455, but less than 0.676 is considered “indeterminate.”

If your NAFLD fibrosis score is indeterminate, you may need to do more tests to rule out advanced fibrosis. You may do imaging tests, biomarker identification for fibrosis, or even a liver biopsy. This scoring system is highly accurate (80- 90% accuracy). If your score is low, your biopsy is unlikely to show evidence of fibrosis.

What is NAFLD Fibrosis Score

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