Serum or Plasma Lactate Concentration (Quantitative)

Why It’s Done

Your doctor may order this test if you have symptoms like rapid breathing, confusion, or fatigue, especially after exercise, illness, or during surgery. It can also help diagnose conditions affecting how your body uses oxygen, such as heart or lung problems, or metabolic disorders.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the test if it’s done during a fasting state. Bring any medications you’re taking to your doctor’s office. The test involves drawing blood from a vein in your arm.

What the Test Results Mean

Lactate levels can rise when your body isn’t getting enough oxygen (hypoxia) or when cells are working hard to produce energy. High levels may signal conditions like heart failure, severe infections, or dehydration. Your doctor will interpret results in the context of your symptoms and overall health.

Common Conditions Monitored

Doctors often check lactate levels in people with heart disease, severe infections (like sepsis), or during surgery to monitor oxygen use and recovery. It can also help track how well treatments for metabolic or respiratory conditions are working.