Guidelines on the use of liver biopsy in clinical practice
Authors: A Grant, J Neuberger
Journal: Gut (1999)

Erlich is credited with the first liver aspiration in 1883 and subsequently the first percutaneous liver biopsy for diagnostic purposes was reported in 1923.1 The technique has been modified since then, and over the past 50 years it has become a central investigation of hepatic disease. The low mortality (0.01–0.17%) and the relatively low morbidity of this procedure have meant that liver biopsy has become widely used.2 

Advances in medical technology and especially in imaging, together with advances in drug therapy have greatly influenced the diagnosis and management of hepatic disease and as a consequence the indications for liver biopsy are changing. In 1991 the British Society of Gastroenterology (BSG), together with the Royal College of Physicians of London, undertook a nationwide audit of percutaneous liver biopsy in 189 health districts.3 It is clear from this audit and from reviewing the literature that there continue to be significant differences in clinical practice with respect to liver biopsy across the United Kingdom, and a lack of standardised protocols between institutions. These guidelines examine the evidence for methods of liver biopsy in adults.

### 2.1 VALIDITY AND GRADING OF RECOMMENDATIONS

The guidelines have been produced to conform with the North of England evidence-based guidelines development project.4 5 

#### 2.1.1  Categories of evidence

The strength of evidence used to formulate these guidelines was graded according to the following system: 

Ia
:   Evidence obtained from meta-analysis of randomised controlled trials.
Ib
:   Evidence obtained from at least one randomised controlled trial.
IIa
:   Evidence obtained from at least one well designed controlled study without randomisation.
IIb
:   Evidence obtained from at least one other type of well designed, quasi-experimental study.
III
:   Evidence obtained from well designed, non-experimental descriptive studies such as comparative studies, correlation studies and case studies.
IV
:   Evidence obtained from expert committee reports or opinions or clinical experiences of respected authorities.



The evidence category is indicated after the citations in the reference section at the end of these guidelines.

#### 2.1.2  Grading of recommendations

The strength of each recommendation is dependent on the category of the evidence supporting it, and is graded according to the following system: 

A
:   Requires at least one randomised controlled trial as part of the body of literature of overall good quality and consistency addressing the specific recommendation (evidence categories Ia, Ib).
B
:   Requires the availability of clinical studies without randomisation on the topic of recommendation (evidence categories IIa, IIb, III).
C
:   Requires evidence from expert committee reports or opinions or clinical experience of respected authorities, in the absence of directly applicable clinical studies of good quality (evidence category IV).



### 2.2 SCHEDULED REVIEW OF GUIDELINES

As methods of diagnosis and tissue sampling change, new evidence will come to light and the content and evidence base for these guidelines should be reviewed frequently.

### 3.1 PERCUTANEOUS LIVER BIOPSY

Percutaneous liver biopsy may be classified according to the site of entry of the …