The liver is vital to overall health, performing more than 500 essential functions. It is the body’s largest solid organ, located beneath the rib cage in the upper right abdomen.

Among its key roles are filtering toxins from the blood, regulating blood sugar, supporting blood clotting, and carrying out hundreds of other critical processes, according to Columbia Surgery.

About 4.5 million Americans are living with some form of liver disease. In many cases, symptoms don’t appear until the condition has progressed. However, recognizing early warning signs may help detect liver problems before they become severe.

Here are several subtle symptoms to watch for:

• Persistent fatigue. More than half of people with liver disease report ongoing tiredness and low energy, according to the National Institutes of Health. Fatigue may be accompanied by muscle weakness, brain fog, memory issues, and poor sleep quality — which can further worsen exhaustion.

• Yellowing of the eyes or skin. If liver disease progresses to cirrhosis, the liver can lose its ability to function properly. As bile builds up in the bloodstream, it can cause jaundice — a yellowish tint to the skin and whites of the eyes.

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• Loss of appetite. Liver disease may increase levels of leptin, a hormone that suppresses appetite, potentially leading to reduced food intake.

• Easy bruising or itching. According to AARP, bile salt buildup in the blood can irritate the skin, causing persistent itching. Some people may also develop spider angiomas — small red or purple spots beneath the skin that resemble a spider’s body and legs. Increased bruising can also occur as liver function declines.

Experts say early testing is key. Dr. Jennifer Lai, a hepatologist at the University of California, San Francisco’s Department of Medicine, recommends an annual comprehensive metabolic panel — a routine blood test often covered by insurance.

The test measures various substances in the blood, including liver enzymes such as alkaline phosphatase, which can help detect liver damage.