Paul Ehrlich is credited with performing the first percutaneous liver biopsy in 1883 in Germany. After Menghini reported a technique for "one-second needle biopsy of the liver" in 1958， the procedure became more widely used. The average duration of the intrahepatic phase of previous liver-biopsy techniques had been 6 to 15 minutes.

　　Liver biopsy is usually the most specific test to assess the nature and severity of liver diseases. In addition， it can be useful in monitoring the efficacy of various treatments. There are currently several methods available for obtaining liver tissue： percutaneous biopsy， transjugular biopsy， laparoscopic biopsy， or fine-needle aspiration guided by ultrasonography or computed tomography （CT）. Each of these methods has advantages and disadvantages.

　　The size of the biopsy specimen， which varies between 1 and 3 cm in length and between 1.2 and 2 mm in diameter， represents 1/50,000 of the total mass of the liver. Usually， for evaluation of diffuse liver disease， a specimen of 1.5 cm in length is adequate for a diagnosis to be made. The number of portal triads present in the specimen is important； most hepatopathologists are satisfied with a biopsy specimen containing at least six to eight portal triads， especially in cases of chronic liver disease in which the extent of injury may vary among portal triads. An adequate specimen is usually provided by all the needles currently used for liver biopsy. Specimens obtained with standard thin-bore or spring-loaded needles measure between 1.4 and 1.8 mm in diameter， and those obtained with Menghini or Tru-cut needles measure up to 2 mm in diameter.

　　The indications for liver biopsy are outlined in Table 1. Even for patients in whom serologic tests point to a specific liver disease （Figure 1 and Figure 2）， a liver biopsy can give valuable information regarding staging， prognosis， and management. For example， in patients with chronic hepatitis C infection， not only is there a poor correlation between symptoms or levels of serum alanine aminotransferase and histologic features of the liver， but also patients with completely normal levels of liver enzymes may be found to have clinically significant fibrosis or cirrhosis on biopsy （Figure 3）. If the patient has mild disease and is infected with genotype 1a or 1b of the hepatitis C virus， a decision may be made to defer treatment. If a decision is made to treat such a patient with a combination of interferon and ribavirin and there are adverse effects， the treatment can be stopped. Conversely， if the patient has moderate-to-advanced disease， treatment will most likely be offered. If the patient has a virologic response and tolerable side effects with treatment， continued therapy would be strongly encouraged. The finding of cirrhosis on liver biopsy will determine the need for further examinations， such as upper endoscopy to rule out esophageal varices and screening for hepatocellular carcinoma with serial determinations of serum alpha-fetoprotein and liver ultrasonography.

Full article:http://content.nejm.org/cgi/content/full/344/7/495