A "liver panel" usually refers to several lab tests performed as a group. Depending on the physician or the laboratory, a liver panel usually includes tests for AST, ALT, bilirubin, and alkaline phosphatase.

Usually, the term "liver enzymes" refers to the AST and the ALT.

The phrase "liver function tests" or "LFTs" is commonly used by patients and physicians. Many patients and physicians use the term to describe the AST and ALT. However, this is not correct--the AST and ALT do not measure the function of the liver.

The true function of the liver is actually best measured by the PT, INR and albumin. Therefore, if you are getting a PT, INR or albumin, these tests can determine how the liver is "functioning."

ALT, or alanine aminotransferase, is 1 of the 2 "liver enzymes." It is sometimes known as serum glutamic-pyruvic transaminase, or SGPT. It is a protein made only by liver cells. When liver cells are damaged, ALT leaks out into the bloodstream and the level of ALT in the blood is higher than normal.

Scroll over image to see liver enzymes leaking into the blood.

A high ALT level often means there is some liver damage, but it may not be related to hepatitis C. It is important to realize the ALT level goes up and down in most patients with hepatitis C. The ALT level does not tell you exactly how much liver damage there is, and small changes should be expected. Changes in the ALT level do not mean the liver is doing any better or any worse. The ALT level does not tell you anything about how much scarring (fibrosis) is in the liver and it does not predict how much liver damage will develop.

• Many patients with hepatitis C will have a normal ALT level.
• Patients can have very severe liver disease and cirrhosis and still have a normal ALT level.
• When a patient takes treatment for hepatitis C, it is helpful to see if the ALT level goes down.

AST, or aspartate aminotransferase, is 1 of the 2 "liver enzymes." It is also known as serum glutamic-oxaloacetic transaminase, or SGOT. AST is a protein made by liver cells. When liver cells are damaged, AST leaks out into the bloodstream and the level of AST in the blood becomes higher than normal. AST is different from ALT because AST is found in parts of the body other than the liver--including the heart, kidneys, muscles, and brain. When cells in any of those parts of the body are damaged, AST can be elevated.

A high AST level often means there is some liver damage, but it is not necessarily caused by hepatitis C. A high AST with a normal ALT may mean that the AST is coming from a different part of the body. It is important to realize that the AST level in most patients with hepatitis C goes up and down. The exact AST level does not tell you how much liver damage there is, or whether the liver is getting better or worse, and small changes should be expected. However, for patients receiving treatment for hepatitis C, it is helpful to see if the AST level goes down.

• The AST level is not as helpful as the ALT level for checking the liver.
• Many patients with hepatitis C will have a normal AST level.
• Patients can have very severe liver disease or cirrhosis and still have a normal AST level.

Bilirubin is a yellowish substance that is created by the breakdown (destruction) of hemoglobin, a major component of red blood cells.

As red blood cells age, they are broken down naturally in the body. Bilirubin is released from the destroyed red blood cells and passed on to the liver. The liver excretes the bilirubin in fluid called bile. If the liver is not functioning correctly, the bilirubin will not be properly excreted. Therefore, if the bilirubin level is higher than normal, it may mean that the liver is not functioning correctly.

• Levels of bilirubin in the blood go up and down in patients with hepatitis C.
• When bilirubin levels remain high for prolonged periods, it usually means there is severe liver disease and possibly cirrhosis.
• High levels of bilirubin can cause jaundice (yellowing of the skin and eyes, darker urine, and lighter-colored bowel movements).
• Elevated bilirubin levels can be caused by reasons other than liver disease.
• Total bilirubin is made up of 2 components: direct bilirubin and indirect bilirubin.
• Direct bilirubin + indirect bilirubin = total bilirubin.

Albumin is a protein made by the liver. Albumin prevents fluid from leaking out of blood vessels into tissues.

A low albumin level in patients with hepatitis C can be a sign of cirrhosis (advanced liver disease). Albumin levels can go up and down slightly. Very low albumin levels can cause symptoms of edema, or fluid accumulation, in the abdomen (called ascites) or in the leg.

• A low albumin level can also come from kidney disease or malnutrition or acute illness.
• A low albumin level causing fluid overload is often treated with diuretic medications, or "water pills."

Prothrombin is a protein made by the liver. Prothrombin helps blood to make normal clots. The "prothrombin time" (PT) is one way of measuring how long it takes blood to form a clot, and it is measured in seconds (such as 13.2 seconds). A normal PT indicates that a normal amount of blood-clotting protein is available.

When the PT is high, it takes longer for the blood to clot (17 seconds, for example). This usually happens because the liver is not making the right amount of blood clotting proteins, so the clotting process takes longer. A high PT usually means that there is serious liver damage or cirrhosis.

• Some patients take a drug called Coumadin (warfarin), which elevates the PT for the purpose of "thinning" the blood. This is not related to having liver disease because it is the Coumadin causing the PT to be high.
• The test called INR measures the same factors as PT and is used instead of PT by many doctors. See "INR."

Alkaline phosphatase (often shortened to alk phos) is an enzyme made in liver cells and bile ducts. The alk phos level is a common test that is usually included when liver tests are performed as a group.

A high alk phos level does not reflect liver damage or inflammation. A high alk phos level occurs when there is a blockage of flow in the biliary tract or a buildup of pressure in the liver--often caused by a gallstone or scarring in the bile ducts.

• Many patients with hepatitis C have normal alk phos levels.
• Hepatitis C treatment usually does not affect alk phos levels.
• Alk phos is produced in other organs besides the liver--it is also found in the bones and the kidneys.
• If your alk phos level is high, your doctor will probably order additional tests to determine why.

International normalized ratio (INR) is blood-clotting test. It is a test used to measure how quickly your blood forms a clot, compared with normal clotting time.

A normal INR is 1.0. Each increase of 0.1 means the blood is slightly thinner (it takes longer to clot). INR is related to the prothrombin time (PT). If there is serious liver disease and cirrhosis, the liver may not produce the normal amount of proteins and then the blood is not able to clot normally. When your doctor is evaluating the function of your liver, a high INR usually means that the liver is not working as well as it could because it is not making the blood clot normally.

• Some patients take a drug called Coumadin (warfarin), which elevates the INR, for the purpose of "thinning" the blood.
• The INR is another way of measuring the blood-clotting time and it is easier to determine than the PT.

Platelets are cells that help the blood to form clots. The platelet number or "platelet count" in the blood is measured as part of the complete blood count (CBC).

Platelet counts in a patient who has cirrhosis are often low. But low platelet counts can also come from other causes, including certain medications. Interferon treatment can reduce platelet counts. When the platelet count is extremely reduced, this condition is known as "thrombocytopenia." If a platelet count is too low, the patient cannot make normal clots and may bruise more easily.

• If the platelet count drops too low (below 50,000, for example) when a patient is receiving interferon, doctors may recommend that the interferon dosage be reduced.

Total protein level is a measure of a number of different proteins in the blood. Total protein can be divided into the albumin and globulin fractions.

Low levels of total protein in the blood can occur because of impaired function of the liver.

This is the first test for determining whether you have been infected with hepatitis C. The results will come back as either positive or negative.

If this test result is positive, it means your body was exposed to the hepatitis C virus and made antibodies (for more information, see "Antibody" section under Associated Lab Tests). However, it does not tell you whether you are still infected with hepatitis C. If the antibody test result is positive, you should be tested for hepatitis C RNA (see "Hepatitis C RNA"), which determines whether you are chronically infected. The lab might perform this RNA test automatically if your hepatitis C antibody test is positive or your doctor might need to order the Hepatitis C RNA test separately.

If the antibody test result is negative, it means you have not been infected with the hepatitis C virus, and further testing for hepatitis C usually is not needed.

• After a successful course of treatment for hepatitis C, the hepatitis C antibody remains detectable, but the hepatitis C RNA will be undetectable.
• Any patient with a positive test result for the hepatitis C antibody should have additional tests to determine whether or not the virus is still active.

The qualitative HCV RNA tests use either a process called polymerase chain reaction (PCR) or a process called transcription-mediated amplification (TMA). Either type of qualitative test will report whether the hepatitis C virus is present in the bloodstream or not. The result is reported as either "detected" or "not detected."

If a qualitative RNA test is positive (detected), then it is confirmed that the patient has chronic hepatitis C. The "qualitative" test is more accurate than the "quantitative" test because qualitative tests are able to detect very low levels of the virus.

• If a patient has a quantitative test that shows no detectable virus, but has a positive result with the qualitative test, it means there is a very low level of virus that can be detected only with the qualitative test.
• The qualitative test will show a negative result when patients have a successful response to interferon treatment.
• The qualitative test result also will be negative when patients clear the hepatitis C virus on their own, soon after infection, or "spontaneously."

The quantitative HCV RNA tests use either a process called polymerase chain reaction (PCR) or transcription-mediated amplification (TMA) or signal amplification (branched DNA). These are all "quantitative" techniques and will give an actual level of HCV RNA -- a measurement of the amount of hepatitis C virus in the blood. The result will be an exact number, such as "1,215,422 IU/L." Many people refer to the quantitative measurement as the hepatitis C "viral load."

There are 2 situations in which a quantitative test is useful:

The quantitative HCV RNA test is checked before a patient starts treatment.

For each patient, the result can be described as either a "high" viral load, which is usually >800,000 IU/L, or a "low" viral load, which is usually <800,000 IU/L. Knowing the viral load before starting treatment is useful because patients with "high" viral loads can have a difficult time getting the virus to become completely undetectable on treatment. Patients with "low" viral loads have a better chance of getting their virus to become completely undetectable on treatment.

The quantitative HCV RNA test is used to monitor a patient who is currently on treatment.

The response to treatment is considered good when the quantitative HCV RNA measurement drops and the virus eventually becomes completely undetectable.

• The viral load measurement does not tell us anything about the severity of a patient's liver disease or the degree of fibrosis (scarring). For that information, the patient would need a liver biopsy.
• It is not necessary to check the viral load repeatedly unless a patient is on treatment or is considering treatment.
• If a quantitative HCV RNA result is reported as "<615 IU/L," this means that the quantitative test cannot measure the hepatitis C virus. It may mean that there is no detectable HCV RNA at all, but it may mean that the level of virus is just too low for the test to pick it up. A qualitative test should then be performed to see if there is any detectable hepatitis C virus at all (see previous screen: "Hepatitis C RNA Qualitative Testing").
• If a quantitative HCV RNA results is "<615 IU/L" but the qualitative test is "detected" then the hepatitis C virus is present in the bloodstream, but at a very very low level, too low to be measured by a quantitative test.

The hepatitis C recombinant immunoblot assay (RIBA) is the confirmation test for the hepatitis C antibody.

If the result of the HCV RIBA is positive, this confirms that the detection of a hepatitis C antibody (anti-HCV) was a true positive, meaning that there has been infection with hepatitis C in the past.

If the HCV RIBA result is negative, it means there has not been infection with hepatitis C. If an earlier hepatitis C antibody (anti-HCV) test had been positive, then this was a false positive.

• Even if the HCV RIBA result is positive, only the test of HCV RNA (viral load) can detect whether the hepatitis C virus is still present in the body.
• HCV RIBA is not a test that is needed for most patients. Usually, it is performed by blood banks to check for hepatitis C in people who donate blood.

The hepatitis C genotype is a type or "strain" of hepatitis C virus. There are 6 genotypes of hepatitis C around the world. In the United States, 3 genotypes are common:

• Genotype 1
• Genotype 2
• Genotype 3

These can be further specified as:

• Genotype 1a or 1b
• Genotype 2a or 2b
• Genotype 3a or 3b

The genotype of hepatitis C does not change over time. It needs to be tested only once.

Knowing the genotype of hepatitis C for each patient is very important information because hepatitis C treatment works differently for different genotypes. In general, genotype 1 is much more "resistant" to hepatitis C treatment and genotypes 2 and 3 are much more "sensitive" to treatment.

Genotype 1 (more difficult to treat)

Approximately 72% of Americans with hepatitis C have genotype 1 Chance of clearing hepatitis C virus is 42-46% Treatment usually lasts for 1 year Ribavirin dosage usually is higher than that required to treat other genotypes

Genotype 2 (easier to treat)

Approximately 10% of Americans with hepatitis C have genotype 2 Chance of clearing hepatitis C virus is 65-80% Treatment usually lasts for 6 months Ribavirin dosage usually is lower than that required to treat genotype 1

Genotype 3 (easier to treat)

Approximately 6% of Americans with hepatitis C have genotype 3 Chance of clearing hepatitis C virus is 65-80% Treatment usually lasts for 6 months Ribavirin dosage usually is lower than that required to treat genotype 1

The viral load of hepatitis C refers to the amount of virus present in the bloodstream. This is usually measured with the hepatitis C RNA quantitative test.

This test measures the total number of white blood cells (WBCs). There are 5 main types of WBCs: neutrophils, eosinophils, basophils, monocytes, and lymphocytes. Each type does a slightly different job. All of them help fight infection.

WBCs are produced in the bone marrow, an area in the middle of many bones. Low WBC "counts"may develop as a side effect of interferon treatment. A low WBC count may be caused by cirrhosis of the liver, alcohol use, medications, or other medical conditions.

Neutrophils are a type of white blood cell. Your neutrophil level is also known as the absolute neutrophil count (ANC).

Neutrophils play a key role in inflammation, formation of pus, and destruction of bacteria. Your doctor will check your ANC regularly if you are taking interferon treatment. If the ANC falls too low, your doctor may reduce the dosage of interferon treatment. Additionally, if the ANC falls too low, your doctor may prescribe additional medication to try to boost the ANC back up.

• The ANC is more important than the total WBC count in terms of determining interferon dosages.
• Even if the ANC falls during interferon treatment, it will return to its normal level once treatment is stopped.
• Your total WBC count includes neutrophils plus the 4 other types of WBCs (eosinophils, basophils, monocytes, and lymphocytes).
• Laboratories will report both the total WBC count and the ANC.

Hemoglobin is a protein within red blood cells. Hemoglobin allows red blood cells to carry oxygen to the rest of the body.

Measuring hemoglobin levels helps to estimate the number of red blood cells in the body. A low hemoglobin level is referred to as "anemia." If hemoglobin levels are very low, patients may feel tired easily.

• The hemoglobin level is related to the hematocrit (see next screen: "Hematocrit").
• Low hemoglobin levels can develop during treatment with interferon and ribavirin.
• Often, lowering the dosage of ribavirin will help bring the hemoglobin level back up.
• Often, a medication called Epogen can be used by patients receiving treatment to bring the hemoglobin level back up.

The hematocrit is sometimes known as "red blood cell count." The hematocrit is the percentage of red blood cells in the total contents of your blood.

A low hematocrit is referred to as "anemia." If the hematocrit is very low, patients may feel tired easily.

• The hematocrit is directly related to the hemoglobin level (see previous screen: "Hemoglobin").
• Low hematocrits can develop during treatment with interferon and ribavirin.
• Often, lowering the dosage of ribavirin will help bring the hematocrit back up.
• Often, a medication called Epogen can be used by patients receiving treatment to bring the hematocrit back up.

The level of creatinine in your body is a marker of kidney function. Creatinine comes from the breakdown of creatine, a muscle protein. Properly functioning kidneys remove creatinine from the blood.

High levels of creatinine mean that the kidneys are not functioning normally. When creatinine levels rise gradually, there are not usually any symptoms, and the higher levels can be detected only with blood tests.

• Certain medications can cause high levels of creatinine.
• A high creatinine level is sometimes referred to as "renal insufficiency."
• If your creatinine level is too high, you may not be able to receive hepatitis C treatments.

TSH is a hormone produced by the pituitary gland in the brain. TSH causes the thyroid gland (located in the neck) to produce thyroid (T4 and T3).

Having a high TSH level means you are "hypothyroid." Symptoms can include fatigue, constipation, and weight gain. When there are low levels of thyroid hormone (hypothyroidism), the TSH becomes elevated as the body tries to increase thyroid production.

Having a low TSH level means you are "hyperthyroid." Symptoms can include weight loss and nervousness. When there are high levels of thyroid hormone (hyperthyroidism), the TSH falls as the body tries to slow thyroid production.

• Interferon treatment can cause thyroid changes, so you could see a TSH level rise or fall when you are receiving interferon.
• Occasionally, patients on interferon need to take medication to correct their TSH levels.
• Hepatitis C itself also can cause thyroid changes, even without the interferon treatment.
• In general, thyroid problems are common and occur without hepatitis C.

Glucose is also called "blood sugar." It comes from the breakdown of foods and from production of glucose by the liver.

When the glucose (or blood sugar) level is higher than normal, this is known as "hyperglycemia." Patients whose fasting glucose levels are higher than 126 mg/dL are considered to have diabetes mellitus. Patients who have hepatitis C and have diabetes mellitus may have a more difficult time controlling their glucose while receiving interferon treatment.

• Most people who have a family history of diabetes, are overweight, or are older than 50 should have a fasting glucose level checked by their doctor.
• If you develop diabetes, it is not necessarily related to your hepatitis C.
• If you already have diabetes, it is very important to work to get your glucose levels well controlled. Poorly controlled diabetes can lead to "fatty liver" in addition to the hepatitis C infection of the liver.
• Fatty liver and hepatitis C together can make liver disease much worse.

AFP is a protein that is present in patients with liver disease. AFP is also a "tumor marker" and may be used to see if a patient has liver cancer. (Liver cancer is also called hepatocellular carcinoma).

A high level of AFP might mean that a patient has liver cancer. However, sometimes the AFP is high when there is active liver disease but no cancer. Usually, the AFP test needs to be interpreted by a doctor in combination with pictures of the liver taken with ultrasound or CT scan.

• An elevated AFP level needs to be interpreted by your doctor. A high AFP level may just mean you have an active liver.
• AFP can be elevated in other types of cancers and in a normal pregnancy.

Antibodies are part of the immune system's response to infection. Once an infection has taken place, the body makes antibodies, which become detectable in the bloodstream. Different antibodies fight different infections.

If you have a positive test result for a specific antibody, it means that your body has had an immune response to that specific infection. It does not necessarily mean you are still infected--it does mean that you were infected at some point in the past.

The hepatitis C antibody is explained under Hepatitis C tests.

A positive test result means you have been infected with hepatitis A in the past or were vaccinated against hepatitis A in the past but are now immune (protected) against being infected with hepatitis A virus in the future.