NASH is a silent disease. Consequently, NASH patients can remain unaware of their liver condition until the disease progresses to more serious and life-threatening stages. Thus, there is a major challenge related to NASH diagnosis: the early identification of patients at risk of progressing to most advanced stages of NASH.
CURRENT GOLD STANDARD: LIVER BIOPSY
The current gold standard to formally diagnose a patient suspected of having NASH is a liver biopsy. But there exists a real bottleneck which needs to be overcome. Although this invasive test could be performed by hepatologists, the number of these specialists who have both the expertise and comfort to execute, order or interpret a liver biopsy is very low as compared to the number of suspected NASH patients. Besides, liver biopsies are costly surgical acts, and as invasive procedures they present a (minor) risk to the patient, including the possibility of pain and bleeding.
OTHER EXISTING DIAGNOSTIC METHODS
Alternative diagnostic tests for NASH and fibrosis include imaging-based techniques:
- Ultrasound (NAFLD)
- MRI (NAFLD)
- Transient elastography (NAFLD, Fibrosis)
- Ultrasound Elastography (Fibrosis)
- MRE (Fibrosis)
These diagnostic tools are all non-invasive, which is a major advantage to the patient, however, none of these general tests were originally designed to diagnose all features of NASH: fat, necro-inflammation, and fibrosis. Furthermore, each of these tests requires a fairly large capital investment by the physician practice which is why most of these techniques have limited availability for patients across the world.
So not only do imaging techniques lack precision when it comes to accurately stratifying patients by disease stage (for instance based on NAFLD Activity Score – or NAS – and fibrosis stages, from F0 to F4), but they are also characterized by a limited access due to costs and to a limited number of points of care able to perform.
TOMORROW: DIAGNOSIS WITH A SIMPLE BLOOD SAMPLE?
For many years, specialists have been using routine blood tests (e.g. liver enzymes (AST, ALT), platelets) to quantify a patient’s risk of having liver disease. However, these general biomarkers are not sufficient on their own to be used as reliable diagnostic tools for NASH and fibrosis.
The development of new NASH diagnostic tools is fortunately very dynamic, and some non-invasive diagnostic tools using blood tests are currently being developed. If the performance of these new tests is validated by public health authorities, these diagnostics would represent more widely available and lower-cost alternatives for specialists (hepatologists, gastroenterologists, diabetologists and endocrinologists) and general practitioners when compared to the liver biopsy and imaging-based approaches.
ASKING FOR DIAGNOSIS
You may wonder whether you are at risk of NASH. Do not hesitate to ask your doctor for more information about the disease and diagnosis options. He or she may be aware of the current reference guidelines on NASH: