The LDH test measures the level of lactate in the blood which is a byproduct of glucose metabolism that is produced when there is not enough oxygen available to the cells to support breaking down of glucose.  Lactate is present in various tissues of the body, including muscles, red blood cells, and the brain. In the bloodstream, lactate is present in the form of lactic acid, which is quickly converted to lactate by the liver. Increased lactate levels in the blood, known as hyperlactatemia, can occur as a result of various conditions, including hypoxia (low oxygen levels), sepsis, shock, heart failure, liver disease, and certain medications. In some cases, hyperlactatemia can be a sign of a medical emergency and requires prompt treatment.

The lactate biochemical plasma test measures the level of lactate in the blood. The levels of lactate in the blood helps the doctor in planning the treatment and understanding the criticality in terms of oxygen levels.

Your doctor will recommend you to take the LDH test in following conditions:

• Diagnose and monitor conditions such as lactic acidosis, which occurs when the body produces too much lactate, or in cases of sepsis, shock, or heart failure.
• Evaluate the severity of certain medical conditions, such as liver or kidney disease, diabetes, or cancer.
• Assess the effectiveness of treatment for conditions such as lactic acidosis or heart failure.
• Help monitor the response to exercise in athletes, especially endurance athletes.
• Monitor critically ill patients in the ICU, as high levels of lactate can indicate organ dysfunction and poor prognosis.
• Detect early stages of sepsis or other life-threatening conditions that affect the body’s ability to produce energy.
• Monitor blood glucose levels in people with diabetes, as high levels of lactate can interfere with glucose metabolism.
• Evaluate the risk of complications during surgery or anesthesia, especially in patients with pre-existing medical conditions.
• Screen for inborn errors of metabolism, which affect the body’s ability to process certain substances, including lactate

The LDH test is a simple blood test with no need for fasting before the test. The blood sample can be taken by the phlebotomist at a pathology lab.