Mandatory medical device diagnostics.
- Liver ultrasonography (ultrasonography of the liver) – for basic diagnosis of nonalcoholic fatty liver (NAFLD) [steatosis hepatis (fatty liver): compare echogenicity liver with renal cortex (normal: isoechogenic; steatosis hepatis: liver more echogenic); sensitivity (percentage of diseased patients in whom the disease is detected by use of the procedure, ie. a positive finding occurs) 60-94%; specificity (probability that actually healthy individuals who do not have the disease in question are also detected as healthy by the procedure) 66-97%; positive predictive value (PPV) for mild steatosis (fatty liver cells) is a maximum of 67%](Sonographic follow-up semiannually for nonalcoholic steatohepatitis, NASH)Note:
- The sensitivity of liver sonography is acceptable only for a degree of steatosis greater than 30%.
- Ultrasound does not allow exclusion of steatosis hepatis or differentiation between NAFLD and NASH (strong consensus).
Optional medical device diagnostics – depending on the results of the history, physical examination, laboratory diagnostics and obligatory medical device diagnostics – for differential diagnosis.
- Electrical impedance analysis (measurement of body compartments/body composition) – for determination of body fat, extracellular body mass (blood and tissue fluid), body cell mass (muscle and organ mass), and total body water, including measurement of body mass index (BMI, body mass index), waist-to-hip ratio (THV), and blood pressure.
- Ultrasound-based shear wave elastography procedures – can be used to rule out advanced liver fibrosis and cirrhosis in NASHNote: It is not possible to differentiate between steatohepatitis and fibrosis using elastography.
- Transient elastography (TE, fibrosan; ultrasound procedure that measures the degree of connective tissue in the liver) – to assess the stage of liver fibrosis.
- Magnetic resonance elastography – allows statements about the degree of fibrosis.
- Magnetic resonance spectroscopy (MR-S) – to accurately quantify fat in the liver; however, has not currently arrived in routine clinical practice due to lack of implementation of appropriate hardware and software. (strong consensus)
- Phosphorus-based magnetic resonance spectroscopy – to distinguish between simple fatty liver and non-alcoholic steatohepatitis.
- Liver puncture (liver biopsy; gold standard):
- Histologic backup may be required to rule out other liver diseases (strong consensus)
- In patients with NAFLD and positive autoantibodies if there is reasonable suspicion of the presence of autoimmune hepatitis (AIH; autoimmune hepatitis), because specific therapeutic consequences may result. (strong consensus) (recommendation)
- Laparoscopy (laparoscopy) – for unclear findings.
Further notes
- A transient elastography of 3,076 liver-healthy adults from the Barcelona metropolitan area found increased liver stiffness (≥ 6.8 kPa) in 9% of study participants. Those affected were offered a liver biopsy; 92 of those agreed. Physicians diagnosed non-alcoholic fatty liver disease (NAFLD) in 81 participants and alcoholic liver disease in seven. The remaining four patients showed no histological (fine tissue) abnormalities.
- Calculation of the noninvasive fibrosis score (eg, NAFLD fibrosis score; parameters age, body mass index (BMI; body mass index (BMI)), diabetes mellitus, AST (GOT), ALT (GPT), platelets, and albumin): NAFLD fibrosis score
