A liver screen, also known as a liver panel or liver function test (LFT), is typically performed by taking a blood sample to analyze various enzymes, proteins, and substances produced by the liver.
Here's a breakdown of the process:
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Preparation: No special preparation is usually required, but your doctor may instruct you to fast (avoid eating or drinking anything other than water) for a certain period before the test, depending on what other tests are being performed simultaneously. Always follow your doctor's specific instructions.
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Blood Draw:
- A healthcare professional (phlebotomist, nurse, or doctor) will locate a suitable vein in your arm, usually on the inner elbow or the back of your hand.
- The area will be cleaned with an antiseptic wipe.
- A tourniquet (elastic band) may be tied around your upper arm to make the veins more visible.
- A small, sterile needle will be inserted into the vein.
- Blood will be collected into one or more vials or tubes attached to the needle. You might feel a brief sting or pinch.
- Once enough blood is collected, the needle is removed, and a cotton ball or gauze is placed over the puncture site.
- Pressure is applied to the site for a few minutes to stop the bleeding.
- A bandage is applied to keep the area clean.
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Laboratory Analysis: The blood samples are then sent to a laboratory where various liver function tests are performed. These tests measure the levels of:
- Alanine transaminase (ALT): An enzyme found primarily in the liver. Elevated levels can indicate liver damage.
- Aspartate transaminase (AST): Another enzyme found in the liver and other tissues. Elevated levels can also suggest liver damage.
- Alkaline phosphatase (ALP): An enzyme found in the liver, bile ducts, and bones. High levels can indicate liver or bone problems.
- Bilirubin: A yellow pigment produced during the normal breakdown of red blood cells. The liver helps eliminate bilirubin. High levels can cause jaundice.
- Albumin: A protein made by the liver. Low levels can indicate liver disease.
- Total protein: Measures the total amount of protein in the blood.
- Gamma-glutamyl transferase (GGT): Another enzyme found in the liver.
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Results and Interpretation: The lab results are sent to your doctor, who will interpret them based on your medical history, other test results, and symptoms. Abnormal liver function tests can indicate various liver problems, such as hepatitis, cirrhosis, fatty liver disease, or bile duct obstruction. Further testing may be needed to determine the exact cause.
In summary, a liver screen involves a simple blood draw followed by laboratory analysis to assess the health and function of your liver. The results help healthcare professionals diagnose and monitor liver-related conditions.
