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CSF Valine

Body Fluids

Cerebrospinal Fluid ValineVAL, CSFValine, CSF

Review status

Currently under review

Pending specialist review and validation.

What it shows

CSF Valine measures the amount of valine, an essential branched-chain amino acid, in cerebrospinal fluid. Valine plays a role in energy use and amino acid balance in the brain. Testing the fluid that bathes your brain and spinal cord can show how amino acids are handled within the central nervous system, which may differ from what is seen in blood.

This test is performed on a sample obtained during a lumbar puncture. It is often ordered as part of an amino acid profile when a neurological or metabolic condition is suspected. Laboratories typically use advanced chromatography or mass spectrometry methods to provide accurate identification of valine in CSF.

Why it matters

Your clinician may order CSF valine when there are symptoms such as seizures, developmental concerns, altered mental status, or metabolic crises, or when an inborn error of metabolism such as maple syrup urine disease is being considered. Measuring amino acids in CSF can help determine whether abnormalities seen in blood are also present in the brain, which can guide urgent therapy and long-term management.

Results can also help monitor response to dietary therapy or specialized formulas and support adjustments during illness or physiologic stress. Because the sample is collected by lumbar puncture, your care team will weigh the potential benefits against procedure-related discomforts such as headache and discuss the plan with you.

Understanding your results

Your report will place your result in the context of the laboratory’s reference interval for CSF. Higher-than-expected values may be seen with certain metabolic disorders that raise branched-chain amino acids, with high protein intake or supplements, or during infusion therapies containing amino acids. Lower-than-expected values can occur with poor intake, prolonged catabolism, or specimen issues.

Interpretation is based on the whole clinical picture rather than a single value. Clinicians often compare CSF valine with amino acid levels in blood and urine, look for patterns in related amino acids, and consider symptoms and timing. If results are unexpected, your clinician may repeat testing, review collection and handling details, or order additional studies such as acylcarnitines, urine organic acids, enzyme assays, or genetic testing. Referral to a metabolic or neurology specialist may be recommended.

Reference ranges

325 umol/L
All sexes
0 days – 150 years

Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.

Factors that could impact CSF Valine

  • Diet and fasting status

    Recent high protein intake, specialized formulas, or fasting can shift amino acid levels and influence CSF findings. Tell your clinician about diet, supplements, and feeding schedules.

  • Timing and clinical state

    Illness, fever, metabolic stress, or parenteral nutrition can change amino acid patterns. The timing of collection relative to symptoms or treatments affects interpretation.

  • Blood contamination of CSF

    A traumatic tap with red blood cells in the CSF can introduce plasma amino acids and falsely raise measured valine. Laboratory review of CSF cell counts helps assess this issue.

  • Specimen handling and storage

    Delayed processing, incorrect tube type, or inadequate freezing can degrade amino acids or alter results. Proper, prompt handling and storage are important for accuracy.

  • Medications and supplements

    Amino acid supplements, high-protein medical foods, or infusion products may increase valine. Provide a full list of medications, vitamins, and nutrition products.

  • Age and special populations

    Newborns and infants have different metabolic needs, and results are interpreted in that context. Clinicians correlate values with age and developmental stage.

2026

References

  1. McGill University Health Centre. (2006, September 13). CSF Valine (Task CD 693405). Laboratory reference ranges.
  2. Clinical and Laboratory Standards Institute. (2018). Analysis of body fluids in clinical chemistry (CLSI guideline C49). CLSI.
  3. American College of Medical Genetics and Genomics. (2022). ACT sheet and confirmatory algorithm: Elevated branched-chain amino acids.
  4. Strauss, K. A., & Morton, D. H. (2014). Maple syrup urine disease. In M. P. Adam, et al. (Eds.), GeneReviews. University of Washington, Seattle.