A liver biopsy is a medical procedure performed to obtain a small piece of liver tissue for diagnostic testing. Liver biopsies are sometimes called percutaneous liver biopsies, because the tissue sample is obtained by going through the patient's skin.
A liver biopsy is usually done to diagnose a tumor, or to evaluate the extent of damage that has occurred to the liver because of chronic disease. Biopsies are often performed to identify abnormalities in liver tissues after imaging studies have failed to yield clear results.
A liver biopsy may be ordered to evaluate any of the following conditions or disorders:
- hemochromatosis, which is a condition of excess iron in the liver.
- repeated abnormal results from liver function tests
- unexplained swelling or enlargement of the liver
- primary cancers of the liver, such as hepatomas, cholangiocarcinomas, and angiosarcomas
- metastatic cancers of the liver
Some patients should not have percutaneous liver biopsies. They include patients with any of the following conditions:
- a platelet count below 60, 000
- a longer-than-normal prothrombin time
- a liver tumor that contains a large number of blood vessels
- a history of unexplained bleeding
- a watery (hydatid) cyst
- an infection in either the cavity around the lungs, or the diaphragm
Percutaneous liver biopsy is done with a special hollow needle, called a Menghini needle, attached to a suction syringe. Doctors who specialize in the digestive system or liver will sometimes perform liver biopsies. But in most cases, a radiologist (a doctor who specializes in x rays and imaging studies) performs the biopsy. The radiologist will use computed tomography scan (CT scan) or ultrasound to guide the choice of the site for the biopsy.
An hour or so before the biopsy, the patient may be given a sedative to help relaxation. He or she is then asked to lie on the back with the right elbow to the side and the right hand under the head. The patient is instructed to lie as still as possible during the procedure. He or she is warned to expect a sensation resembling a punch in the right shoulder, but to hold still in spite of the momentary feeling.
The doctor marks a spot on the skin where the needle will be inserted and thoroughly cleanses the right side of the upper abdomen with an antiseptic solution. The patient is then given an anesthetic at the biopsy site.
The needle with attached syringe is inserted into the patient's chest wall. The doctor then draws the plunger of the syringe back to create a vacuum. At this point the patient is asked to take a deep breath, exhale the air and hold their breath at the point of complete exhalation. The needle is inserted into the liver and withdrawn quickly, usually within two seconds or less. The negative pressure in the syringe draws or pulls a sample of liver tissue into the biopsy needle. As soon as the needle is withdrawn, the patient can breathe normally. Pressure is applied at the biopsy site to stop any bleeding, and a bandage will be placed over it. The entire procedure takes 10 to 15 minutes. Test results are usually available within a day.
Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are known to thin the blood and interfere with clotting. These medications should be avoided for at least a week before the biopsy. Four to eight hours before the biopsy, patients should stop eating and drinking.
The patient's blood will be tested prior to the biopsy to make sure that it is clotting normally. Tests will include a platelet count and a prothrombin time. Doctors will also ensure that the patient is not taking any other medications, such as blood thinners like Coumadin, that might affect blood clotting.
Liver biopsies are outpatient procedures in most hospitals. After the biopsy, patients are usually instructed to lie on their right side for about two hours. This provides pressure to the biopsy site and helps prevent bleeding. A nurse will check the patient's vital signs at regular intervals. If there are no complications, the patient is sent home within about four to eight hours.
Patients should arrange to have a friend or relative take them home after discharge. Bed rest for a day is recommended, followed by a week of avoiding heavy work or strenuous exercise. The patient can resume eating a normal diet.
Some mild soreness in the area of the biopsy is normal after the anesthetic wears off. Irritation of the muscle that lies over the liver can also cause mild discomfort in the shoulder for some patients. Tylenol can be taken for minor soreness, but aspirin and NSAIDs are best avoided. Patients should call their doctor if they have severe pain in the abdomen, chest or shoulder, difficulty breathing, or persistent bleeding. These signs may indicate that there has been leakage of bile into the abdominal cavity, or that air has been introduced into the cavity around the lungs.
The risks of a liver biopsy are usually very small. When complications do occur, over 90% are apparent within 24 hours after the biopsy. The most significant risk is internal bleeding. Bleeding is most likely to occur in elderly patients, in patients with cirrhosis, or in patients with a tumor that has many blood vessels. Other complications from percutaneous liver biopsies include the leakage of bile or the introduction of air into the chest cavity (pneumothorax). There is also a small chance that an infection may occur, or an internal organ such as the lung, gallbladder, or kidney could be punctured.
After the biopsy, the liver sample is sent to the pathology laboratory for study under a microscope. A normal (negative) result would find no evidence of cancer or other disease in the tissue sample.
Brown, Kyle E., et al. "Liver Biopsy: Indications, Technique, Complications and Interpretation" In Liver Disease. Diag nosis and Management, edited by Bacon, Bruce R., and Adrian M. Di Bisceglie. Philadelphia, PA: Churchill Livingstone, 2000.
Cahill, Matthew, et al., eds. Everything You Need To Know About Medical Tests. Springhouse, PA: Springhouse Corporation, 1996.
Reddy, K. Rajender, and Lennox J. Jeffers. "Evaluation of the Liver. Liver Biopsy and Laparoscopy." In Schiff's Diseases of the Liver, edited by Eugene R. Schiff, et al. Philadelphia, PA: Lippincott-Raven, 1999.
Bravo, Arturo A., et al. "Liver Biopsy" New England Journal of Medicine 344, no. 7 (February 15, 2001): 495-500.
"Diagnostic Tests." The National Digestive Diseases Information Clearinghouse (National Institutes of Health). <http://www.www.niddk.nih.gov/health/digest/pubs/diagtest/indexhtm>.
Lata Cherath, Ph.D.
QUESTIONS TO ASK THE DOCTOR
- Which medications should I stop taking before the biopsy?
- How soon can I return to my normal activities after the biopsy?
- How soon will I get my results?
—A procedure where a piece of tissue is removed from a patient for diagnostic testing.
—A special needle used to obtain a sample of liver tissue.
—A biopsy in which a needle is inserted and a tissue sample removed through the skin.
—A blood test that determines how quickly a person's blood will clot.
—A person's essential body functions, usually defined as the pulse, body temperature, and breathing rate.