Hepatic Function Profile with Bromocresol Green (BCG) Method (Plasma/Serum)

The BCG (bromcresol green) test is a blood test that measures the level of albumin, a protein made by your liver, in your blood. Albumin helps keep fluid inside your blood vessels, carries hormones, vitamins, and medications throughout your body, and supports tissue growth and healing.

The BCG method evaluates liver function by tracking how quickly your liver removes bromocresol green from your blood. This process reflects your liver’s ability to handle proteins, detoxify substances, and maintain normal metabolic functions. The test may also indirectly assess bile flow and protein synthesis.

A healthcare professional draws a small blood sample from a vein, usually in your arm, and sends it to a laboratory. There, bromcresol green dye is mixed with the sample, where it binds to albumin and causes a color change. An analyzer measures this color change to calculate how much albumin is present, producing your BCG result.

Your blood sample is mixed with bromocresol green dye. The liver then removes the dye, and the remaining concentration in your blood is measured. Lower levels of dye in your blood suggest normal liver function, while higher levels may indicate impaired processing.

Your doctor may order this test to investigate symptoms such as swelling in your legs or abdomen, fatigue, or unexpected weight changes, or to check how well your liver and kidneys are working. It helps detect and monitor conditions like liver disease, kidney disease, malnutrition, and chronic inflammation, and it is often repeated over time to see how well treatment is working.

A BCG test is often used when doctors suspect liver disease, such as hepatitis, cirrhosis, or other conditions affecting bile flow or protein metabolism. It can also be part of routine liver function screening in certain high-risk groups.

This test usually requires very little preparation. You can generally eat and drink as you normally would unless your provider tells you otherwise, especially if it is being done along with other tests that require fasting. Let your care team know about all medicines, vitamins, and supplements you take, and drink plenty of water before your appointment so the blood draw is easier and more comfortable.

No special preparation is typically required, but you may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Avoid excessive alcohol or certain medications that could affect liver function for 24 hours before testing.