Leucine

ChemistryAlso known as: 2-amino-4-methylpentanoic acidAlso known as: L-leucinemg/(24.h)

Measures leucine, an essential amino acid, in serum or plasma collection.

Normal Range
15 – 80 mg/(24.h)
mg/(24.h)
Abnormal Levels
Consult your provider
Specimen Type
Blood

Why This Biomarker Matters

Abnormal leucine levels may indicate serious inherited metabolic disorders like maple syrup urine disease. Early detection through this test prevents severe neurological complications.

Understanding Your Results

Normal Range

15 – 80 mg/(24.h)

Overview

Leucine is an essential branched-chain amino acid crucial for muscle protein synthesis and energy metabolism. A 24-hour urine leucine test measures how much of this amino acid your body is excreting over a full day. Abnormal urinary leucine levels may indicate inherited metabolic disorders like maple syrup urine disease (MSUD), kidney dysfunction, or severe nutritional deficiencies. This test is particularly important in newborn screening and evaluation of patients with neurological symptoms or developmental delays.

Technical Information (LOINC Codes)

Standardized laboratory codes for this biomarker

20649-0Primary
Leucine [Moles/volume] in Serum or Plasma
umol/L
2562-7
Leucine [Mass/time] in 24 hour Urine
mg/(24.h)
2561-9
Leucine [Mass/volume] in Urine
mg/dL
47679-6
Leucine [Moles/volume] in DBS
umol/L
2559-3
Leucine [Presence] in Serum or Plasma
2560-1
Leucine [Mass/volume] in Serum or Plasma
mg/dL
25460-7
Leucine [Moles/time] in 24 hour Urine
umol/(24.h)
22719-9
Leucine [Moles/volume] in Specimen
umol/L
9412-8
Leucine [Moles/volume] in Cerebral spinal fluid
umol/L
55933-6
Leucine [Moles/mass] in Hair
umol/g
26710-4
Leucine [Moles/volume] in Amniotic fluid
umol/dL
25941-6
Leucine [Moles/volume] in 24 hour Urine
umol/L
13403-1
Leucine [Mass/volume] in Amniotic fluid
mg/dL
27323-5
Leucine [Moles/volume] in Urine
nmol/mL
29284-7
Leucine [Presence] in Blood
29293-8
Leucine [Mass/volume] in Blood
mg/dL
32253-7
Leucine [Moles/volume] in Vitreous fluid
umol/L
32254-5
Leucine [Moles/volume] in Body fluid
umol/L
49834-5
Leucine [Presence] in Urine

Available Lab Tests

Order tests that measure this biomarker

Amino Acids (Plasma)

$193.00
Results in 3-7 business days