Leucine Quantitative Plasma Test

This test measures the amount of leucine, an essential amino acid, in your blood plasma.

This test serves the following purposes:

• To diagnose Maple Syrup Urine Disease (MSUD), a rare genetic disorder which impairs the body’s ability to metabolise certain amino acids
• To identify early signs of MSUD, so that timely interventions can prevent complications 
• To monitor the effectiveness of treatment for MSUD

Doctors will recommend this test in case of the following:

• Suspicion or provisional diagnosis of Maple Syrup Urine Disease (MSUD)
• Family history of MSUD
• Symptoms such as poor feeding, vomiting, and lethargy
• Infants undergoing newborn screening for metabolic disorders
• Evaluating patients with other metabolic disorders that affect amino acid metabolism 

Elevated levels of leucine in plasma may indicate MSUD or other disorders affecting amino acid metabolism.

The test is a simple blood draw that takes just a few minutes. A healthcare provider will collect a blood sample from your vein. You may experience mild discomfort or bruising at the injection site.

To prepare for this test, follow these instructions:

• Inform your doctor about any medications or supplements you are taking as they may interfere with your test results.
• Fasting before the test is not compulsory, but your doctor may suggest it.
• Drink plenty of water to stay hydrated before and after the test.

Other tests that may be ordered alongside this test include the following:

• Amino acid analysis: This test measures the levels of different types of amino acids in blood or urine to detect various metabolic disorders.
• Organic acid analysis: This test checks for abnormal levels of organic acids in urine to diagnose metabolic disorders.
• Genetic testing: This helps to identify gene mutations responsible for inherited metabolic disorders.

Quantitative Plasma Leucine, Leucine Assay, or amino acid level testing

Maple Syrup Urine Disease (MSUD) is a rare genetic disorder that leads to the buildup of certain amino acids in the body. This can cause severe neurological damage, developmental delays, coma, and even death if left untreated. Urine with a sweet aroma is one of MSUD's characteristic symptoms, which gives the condition its name.