FibroScan is a non-invasive diagnostic tool used to assess liver health. It evaluates liver stiffness, which can indicate scarring (fibrosis), and measures liver fat content. This method offers a safe alternative to a liver biopsy, a more invasive procedure traditionally used for liver assessment.
How FibroScan Works and What it Measures
FibroScan uses transient elastography, a type of ultrasound. The device sends a low-frequency shear wave through the liver tissue. The speed at which this wave travels is measured; stiffer tissue causes the wave to travel faster. This measurement, expressed in kilopascals (kPa), reflects liver stiffness and the degree of fibrosis.
In addition to stiffness, FibroScan also measures liver fat content using a Controlled Attenuation Parameter (CAP) score. This score, measured in decibels per meter (dB/m), indicates the level of steatosis, or fatty change, in the liver.
Interpreting a Normal Result
A normal FibroScan result for liver stiffness typically falls within 2 to 7 kilopascals (kPa). For most healthy individuals, the measurement is often below 7.0 kPa, with a median around 5.3 kPa. This range generally indicates minimal to no liver fibrosis, suggesting a healthy liver.
A normal result also implies a healthy amount of liver fat, with CAP scores usually below 238 dB/m. While these ranges serve as general benchmarks, slight variations can occur based on individual health factors. A healthcare professional always interprets these results with other medical data for a comprehensive assessment of liver health.
Factors Affecting FibroScan Readings
Several factors unrelated to liver scarring can influence FibroScan readings, potentially leading to temporarily elevated results. Liver inflammation, such as from acute hepatitis, can increase stiffness measurements. Conditions like cholestasis (a blockage of bile flow) or mass lesions within the liver may also affect readings.
Liver congestion, often due to heart failure, can lead to higher stiffness values as the liver becomes engorged with blood or fluid. Transient factors like recent food intake or excessive body mass index (BMI) can also impact measurement accuracy. Healthcare providers consider these influences when interpreting FibroScan results to avoid misdiagnosis.
Understanding Fibrosis Stages
Liver fibrosis is often categorized using a staging system that ranges from F0 to F4, indicating increasing scarring severity. F0 represents no fibrosis, while F1 signifies mild fibrosis. As the scarring progresses, it moves through F2 (moderate fibrosis) and F3 (severe fibrosis).
The most advanced stage, F4, denotes cirrhosis, a condition characterized by extensive and irreversible liver scarring. A normal FibroScan result, typically below 7 kPa, corresponds to F0 or F1, indicating minimal or no significant scarring.