Lab Tests to Monitor Hep C: Test Types & What They Measure
Last updated: July 2023
Physicians who provide care for hepatitis C patients order lab tests to monitor the health of the liver. While serial liver biopsies, as well as some other non-invasive tests such as fibroscan and imaging, are useful tools, they are expensive. Yearly imaging for late stage patients (cirrhosis), and biopsyM/a> repeated every 5 years for untreated patients, seems to be the “gold standard” for monitoring how well the liver is working and if the disease is progressing.
Periodic lab work gives much needed information to the patient’s physician. I will discuss some of the more important lab tests that your doctor may order.
Different lab tests for hepatitis C
Bilirubin is an orange-yellow pigment produced when the liver breaks down red blood cells. The liver excretes the bilirubin in fluid called bile. If the liver is not functioning correctly, the bilirubin will not be properly excreted. Bilirubin is removed from the body through the stool and gives stool its normal color. There are two forms, direct and indirect. When total bilirubin is too high, jaundice occurs.
Alanine aminotransferase (ALT)
ALT is made only in the liver. When the liver is inflamed, it leaks out into the bloodstream. Patients call it a liver function test, but it is not really a test of the liver’s function. The level fluctuates and does not indicate how much damage has occurred. It does not give clues as to the progression of the virus. It confirms inflammation. In the average hepatitis C patient, the level of ALT is 1.5 times the upper range of normal.
Aspartate aminotransferase (AST)
AST is also a protein and it leaks into the bloodstream like ALT. However, AST is made in the liver, heart, kidneys, muscle, and brain. This happens when these organs are damaged.
Albumin is another protein made in the liver. Its function is to prevent fluids from leaking into tissues of the body. It does give the doctor information about the functioning of the liver. Low levels cause edema (fluid accumulation). When it happens in the abdomen it is called ascites. This happens when the liver begins to decompensate in late stage cirrhosis.
Alkaline phosphatase (Alk Phos)
All Phos is a protein made in liver cells and bile ducts. Fibrosis of the bile ducts may cause blockages resulting in elevated levels. Alk Phos is produced in the liver, kidneys, and bones, so physicians may perform other tests to determine why it is elevated.
Prothrombin is another protein made by the liver. It is necessary to help the blood clot. When the clotting time is prolonged (over 17 seconds), the physician knows that there is serious liver damage. This happens in the later stages of cirrhosis.
International Normalized Ratio (INR)
This test is related to prothrombin time. It measures how long the blood takes to clot. A typical result is 1.0. For each tenth of an increase, the blood takes longer to clot. They physician uses this test to learn how well the liver is functioning. A high number is indicative of a liver that is not working well.
Platelets are small disk-shaped cells found in large numbers in blood and help in clotting. Platelets fall below the normal range (150,000 – 450,000) in patients with cirrhosis.
Total Protein is a combination of proteins that fall when the liver is not working properly.
These are the tests that healthcare providers use to monitor hepatitis C patients. Specific results provide the information that the physician needs to properly care for their patients.1,2