Lab Tests for People with Hep C
If you have hepatitis C—or hep C—lab tests will be part of your life for a while. Some you need when your doctor first diagnoses hep C and others you will need regularly. They provide information about your disease progress, your liver’s health, and your treatment. Learning about these lab tests can help you understand why you need them and what they will tell you.
There are lab tests specific for hep C.
Testing for hep C involves more than one test. Each one tells your doctor something about your hep C. They include:
Hep C antibody: This test comes back either positive or negative. If it’s positive, it means you have been exposed to the hep C virus. But the test doesn’t tell you if you still have hep C infection after you’ve been through treatment. Some people clear the acute infection and will react to the antibody test even though they no longer have the virus in their blood.
Hep C RNA qualitative test: This test comes back either detected or not detected. If the test detects hep C RNA in your blood, it means you have an active hep C infection. This test can detect very small amounts of hep C RNA.
Hep C RNA quantitative test: This test comes back as a measurement. It measures the amount of hep C RNA in your blood. It’s useful before starting treatment and to monitor your response to treatment. Generally, a lower viral load before treatment means you’re more likely to respond.
Hep C genotype: This test comes back as a specific genotype—or strain—or the virus. There are six strains of hep C. In the United States, most people have genotype 1—either 1a or 1b. About 25% have genotypes 2 and 3, and a very small number have genotypes 4, 5 and 6. Your genotype will guide your treatment options.
There are lab tests to measure the health of your liver.
Certain lab tests can measure how your liver is functioning. These tests can show if your liver is showing signs of damage, but they can’t really show how much damage. To get a better picture of your liver’s health, your doctor may recommend imaging tests or a biopsy. Here are lab tests your doctor may use to test your liver:
LFT’s (liver function tests): This group of tests usually refers to measuring the levels of liver enzymes—AST, ALT, GGT and GGTP. Liver enzyme levels rise when damage occurs to liver cells.
Bilirubin: This test comes back as a measurement. Bilirubin levels rise when the liver isn’t functioning properly. Very high bilirubin levels can cause jaundice—yellowing of the skin and whites of the eyes.
Albumin: This test comes back as a measurement. The liver makes a protein called albumin, so low serum albumin levels can mean the liver isn’t working correctly. Albumin keeps the fluid part of blood inside your blood vessels. Low albumin levels can allow fluid to leak out and accumulate in the legs and belly.
PT/INR: This test comes back as a number. It measures how quickly your blood clots. If your blood takes too long to clot, it may mean your liver isn’t making enough clotting proteins. This could indicate liver damage.
Platelets: This test comes back as a measurement, as part of a complete blood count. People with cirrhosis often have low platelet counts.
There are lab tests to monitor treatment.
Hep C treatment lasts for weeks and older drugs, especially, are often difficult to take due to side effects. But even on newer drugs, you’ll likely need some lab tests during and after treatment. They include:
Hep C RNA qualitative and quantitative tests: Your doctor will use these tests to judge your response to treatment. A sustained viral response (SVR) means that these tests can no longer detect hep C virus in your blood six months after treatment ends.
WBC’s (white blood cells): This test comes back as a measurement, as part of a complete blood count. If you take interferon, your doctor will order this test to check for low WBC’s.
Neutrophils: This test measures a specific type of white blood cell. Your doctor will order it if you take interferon.
Hemoglobin and hematocrit: These tests come back as measurements. They tell your doctor about your red blood cells. Your doctor will order these tests if you take interferon or ribavirin.
Creatinine: This test tells your doctor about your kidney function. High levels mean your kidneys might not be working properly. Your doctor may need to adjust your hep C treatment if this is the case.
TSH: This test measures your thyroid hormone levels. Hep C infection itself can cause thyroid changes, but so can interferon. Your doctor may check TSH levels periodically.
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